1.1 introduction to computermmghodasaracollege.in/admin-cp/images/download_doc/down...1.1...

Sub.: Computer Fundamental Chapter – 1 B.C.A. Sem-1

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1. Basics of Computers What is Computer? A computer is an electronic device which reduces the mental efforts to solve the problem. OR It is an automatic electronic device for making calculation or controlling operations those are expressible in numerical or logical terms. Computer can operate on various kinds of data. Data Processing Cycle The activities processing of data using a computer is called Data.

1.1 Introduction to Computer Topics Covered

1. Basics of Computers What is Computer Characteristics of Computer Data Processing Cycle

2. Classification of Computer by Data processed 3. History and Generations of Computers 4. Classification of Computer by processing Capabilities 5. History and Generations of Computers 6. Simple Model of Computer

Input Devices. CPU (Central Processing Unit)

7. Output Devices 8. Secondary Storage Devices

Chapter 1


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Data processing consists of three sub activities • Capturing the input data • Manipulating the data and • Managing the output results. Data is raw material use as input and information processed data obtained as output of data processing. Characteristics of computer 1. Automatic:- Computers are automatic machines because once started on a job, they carry on until the job is finished, normally without any human assistance. Computers being machines cannot start them selves. They cannot go out and find their own problem of coded instructions that specify exactly how a particular job is to be done. While the job is in process, the program is stored in the computer, and the parts of the instructions. 2. Speed:- A computer is a very, fast device. It can perform in a few seconds the amount of work that a human being can do in an entire year. If he worked day and night and did nothing else. To put it in a different manner, a computer does in one minute what would take a man his entire lifetime. 3. Accuracy:- The accuracy of a computer is consistently high and the degree of accuracy of a particular computer depends upon this design. But for a particular computer each and every calculation is performed with the same accuracy. 4. Diligence:- A computer is free form monotony (variation), tiredness, lack of concentration, etc. Computers obviously score over human being in doing routine type of jobs, which require great accuracy. If ten lakhs calculations have to be performed, a computer will perform the ten lakhs calculations with exactly the same accuracy and speed as the first one.


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5. Versatility:- Versatility is one of the most wonderful things about the computer. It is preparing the results of particular examination, preparing electricity bills. Computer is capable of performing almost any task provided that the task can be reduce to a series of logical steps.

2. Classification of Computer by Data processed

Analog Computer Analog is a Greek word meaning to find the equality between two units. It is computer that operates on data which is in the form of continuously variable physical quantities such as electrical current, sound waves. Hybrid Computer It is a combination of digital and analog computers combining the good qualities of both. Hybrid computer has the speed of analog computer and the accuracy and efficiency of digital computer. These types of computer are used for the special kind of work. For example, aero plane, radar, submarine.


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Digital Computer Digital computer is a machine based on digital technology. Digital computer gives the output by making necessary calculations from the given data. This type of computer cannot do any measurement. It is used in various fields. For example, calculator.

3. Generation of computers 1. First Generation (1942-55) :- First generation computers were made up of vacuum tubes. These computers were of very big sizes, expensive consume lot of power. For example, ENIAC – Electronic Numerical Integrator And Calculator (1943-46) EDVAC – Electronic Discrete Variable Automatic Computer (1946-52) EDSAC – Electronic Delay Storage Automatic Calculator (1947-49) UNIVAC – Universal Automatic Computer (1951 - 54) Limitations They were too large in size requiring rooms for installation. Thousands of vacuum tubes that were used so it can produce large amount. Hence the air-conditioned required. High power consumption and short life span. Commercial production of these computers was difficult and costly. Limited programming capabilities No portable. 2. Second Generation (1955-64):- The second generation computers were manufactured using transistors instead of vacuum tubes. Compared to vacuum tubes they are in size and having more life. Advantages They were more then 10 times faster than first generation computers. They were much smaller in size then first generation computers. Requiring smaller space for installation. They accept less power than the first generation computers. They were much easier to program and use than the first generation computers.


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Limitations They had more then one transistors to made this type of computers It is very difficult and costly. Repairing charge is very costly. 3. Third Generation (1964-75):- The third generation was based on IC (Integrated Circuits) technology. The IC technology was also known as “microelectronics” technology because it made it possible to integrate larger number of circuit components into very small i.e. less than 5 mm square surface of silicon known as “chip”. Advantages They were much more powerful than the second-generation computers. Smaller in size as compared to second-generation computers. Less power than the second-generation computers. Commercial production was easier and cheaper. They are portable. Limitation Third generation computers were located had to be properly air-conditioned. Highly sophisticated technology and expensive setup was required for the manufacture of IC chips. 4. Forth Generation (1975-89):- The fourth generation computers were also made by IC technology. It is known as Small Scale Integration (SSI). After the advance technology in the production of IC chip it was possible to coordinate 100 components on one chip. It is known as Medium Scale Integration (MSI). Latest and advance IC technology is Very Large Scale Integration (VLSI) in which more then 10 lakes components can be coordinate on one chip. Forth generation computers were based on LSI technology. Advantages The PCs were much smaller and cheaper as compared to previous generations. They consumed much less power than the third-generation computers. They had faster and larger primary memory and secondary storage devices as compared to third-generation computers. PCs are use for office and home usage.


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The PCs of the forth generation made computers affordable even by individuals for their personal use at home. Limitations Highly difficult technology required for the manufacture of LSI chips. 5. Fifth Generation (1989 Onwards):- This generation computers use the ULSI (Ultra Large Scale Integration) for making IC chips. Size of this computer is reduced and speed is increase. These computers are very powerful and compact as compared to forth generation computers. Advantages In this generation PCs are much smaller and handy the PCs of the forth generation. They consume much less power. They have faster and larger primary memory and secondary storage devices as compared to other generation. They are totally general purpose machines. Commercial production of these systems is easier and cheaper.

4. Classification of Computer by processing Capabilities 1. Microcomputer A micro computer’s CPU is a micro processor, which originated in late 1970’s and built around 8 – bit microprocessor chips. An improvement on 8 bit chip technology was see in early 1980s when a series of 16 bit chip namely 8086 and 8088 was introduced by Intel Corporation each one with an advancement over the other. Currently processor named Pentium-II is available in the market. 2. Mini computers A mini computer is a multi-user computer capable of supporting from 10 to hundreds of users simultaneously. Initially microcomputers were 8 bit and 12 bit machines but by 1970s almost all mini computers were 16 bit machines. Mini computers speed, memory, size and other characteristics developed and the minicomputer was then used for various stand alone applications. A 32 mini computer which was called supermini was introduced. It had larger memory and could support more users working simultaneously on the computer in comparison to the previous minicomputers.


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3. Mainframe computer Mainframe computers are generally 32 bit machines or on the higher side. These are suited to big organizations to manage high volume application. Few of the popular mainframe series are MEDHA, Sperry, DEC, IBM, HP, HCL, etc. Mainframe are also used us central host computers in distributed systems. There are several organizations such as banks, insurance companies, hospitals, railways etc, that need to process large number of transactions on-line and require computer systems having data storage and processing capabilities. Mainframe systems are computer systems that are mainly used for handling the bulk of data and information processing of such organizations. Mainframe systems are much bigger and several time more expensive then workstations. A typical mainframe system needs a large room with closely monitored temperature. 4. Super Computer Super computers are the most powerful and the most expensive computers available at a given time. They are primarily used for processing complex scientific applications that require high processing power. For example scientists build models of complex processes and stimulate (motivate) the processes on a super computer. The super computers are used in petroleum industry, aerospace industry, automobile industry, film and TV industry, etc

5. Simple Model of Computer 1. Input Device:- All i/p devices are an electromechanical device that accept data from outside world & translates them into a form the computers interpret (i.e. binary). There are mainly three type of input devices Standard Input Device Pointing Input Device Special Input device


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CPU (Central Processing Unit):-

Input Unit:-

Output Unit:-


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Storage Device:-

There are two types of storage

Arithmetic and Logic Unit (ALU)


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Control Unit (CU)

Internal Memory

Secondary Storage (Auxiliary) Computer systems need to store data on a permanent basis for several days, xseveral months, or even several years. So, an additional memory called auxiliary memory or secondary storage is used with most computer systems. This section of memory is used to store large volume of data on a permanent basis, which can be partially transferred to the primary storage as and when required for processing. Data is stored in secondary storage in the same binary codes as in main storage and is made available to main storage as needed. A wide range of devices and media have been developed for use as secondary storage in computer systems. The popular item used in today’s computer systems are floppy disk, hard disk, CD, DVD, Zip Drive, Pen Drive etc. There are three type of secondary devices:: Magnetic Tape, Magnetic Disk, Optical Disk


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Introduction to Mother board • A motherboard is sometimes alternatively known as the main board, system board, planar board or logic board. • It is a printed circuit board (PCB) found in many modern computers which holds many of the crucial components of the system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals. • Motherboard specifically refers to a PCB with expansion capability. • The term main board is applied to devices with a single board and no additional expansions or capability. • In modern terms this would include controlling boards in televisions, washing machines and other embedded systems. Types of Processors Dual Core A multi-core processor is a single computing component with two or more independent actual central processing units (called "cores"), which are the units that read and execute program instructions. 1. The instructions are ordinary CPU instructions such as add, move data, and branch, but the multiple cores can run multiple instructions at the same time, increasing overall speed for programs amenable to parallel computing.

1.2 Internal/External parts used with Computer

Topic Covered 1. Introduction to Motherboard 2. Types of Processors

Dual Core, Core 2 Duo, i2, i3 etc…… 3. Memory Structure and types of Memory

RAM (SRAM, DRAM, SD, DDR, etc.) ROM (ROM, PROM, EPROM, EEPROM, etc)

4. Slots ISA Slots, PCI Slots, Memory Slots,SATA

5. Sockets 6. Cables

Serial Cable, Parallel Cable, USB Cable,HDMI 7. Ports

USB, Serial, Parallel, PS2 8. UPS 9. Graphic Cards 10. Network card, Sound Card


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2. Manufacturers typically integrate the cores onto a single integrated circuit die known as a chip multiprocessor or CMP, or onto multiple dies in a single chip package. Core 2 duo • This article is about The Core 2 Solo/Duo/Quad/Extreme line of Intel processors. • For the overall Intel Core brand, see Intel Core. For the micro architecture used in Core 2 • Core 2 is a brand encompassing a range of Intel's consumer 64-bit single-, dual-, and quad-core microprocessors based on the Core micro architecture • The single- and dual-core models are single-die, whereas the quad-core models comprise two dies, each containing two cores, packaged in a multi-chip module. • The introduction of Core 2 relegated the Pentium brand to the mid – range market, laptop and desktop CPU lines, which previously had been divided into the Pentium 4, Pentium D, and Pentium M brands. • The Core 2 brands was introduced on 27 July 2006, comprising the Solo (single-core), Duo (dual-core), Quad (quad-core), and in 2007, the Extreme (dual- or quad-core CPUs for enthusiasts) sub brands. • Intel Core 2 processors with vPro technology (designed for businesses) include the dual-core and quad-core branches. i2, i3 etc… • There are only the Core i3, Core i5, and Core i7 processors. • Core i2s and Core i6s do not exist. Basically, i3, i5, and i7 are monitors to differentiate different lines of processors that are aimed at different types of consumers. • The Core i3 is aimed for consumers who do video editing, web browsing, and light gaming. • The Core i5 is aimed at consumers who do content creation and moderate gaming. • The Core i7 is aimed at people who do content creation or render thing, and heavy gaming. Memory structure and Types of Memory • Memory had a two types 1. Primary memory 2. Secondary memory


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• Primary memory is a temporary storage area that is built into the computer hardware and in which instructions and data of a program reside mainly when the CPU is executing the program. • Physically this memory consists of some chips either on the motherboard or on a small circuit board attached to the motherboard of a computer system. • This built-in memory allows the CPU to store and retrieve data very quickly. • Primary memory mainly contains two parts:: 1. volatile memory (RAM) and 2. Non-volatile memory (ROM, PROM, EPROM, EEPROM).

I.RAM (Random Access Memory):- • Primary memory usually referred to as Random Access Memory (RAM) because it is possible to randomly select and use any location of this memory to directly store and retrieve data and instructions. • It is also known as read/write memory because information can be read from a RAM chip and can also be written into it. • Physically, this memory consists of some integrated circuit chips called IC either on the mother board or on a small circuit board attached to the motherboard. • This is volatile memory (temporary memory). If power supply is lost then information is destroy. • RAM chips are of two types – dynamic and static. • A dynamic RAM called DRAM uses an external circuitry to periodically regenerate or refresh the storage charge to retain the stored data. • SD and DDR RAM are a types of dynamic RAM. • A static RAM called SRAM does not need any special regeneration circuits to retain the stored data. SRAM (Static random-access memory) • Static random-access memory (SRAM) is a type of semiconductor memory. • The term static differentiates it from dynamic RAM (DRAM) which must be periodically refreshed. • SRAM exhibits data reminisce, but is still volatile in the conventional sense that data is eventually lost when the memory is not powered. DRAM (Dynamic random-access memory) • Dynamic random-access memory (DRAM) is a type of RAM that stores each bit of data in a separate capacitor within an integrated circuit.


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• The capacitor can be either charged or discharged these two states are taken to represent the two values of a bit, conventionally called 0 and 1. • The main memory (the "RAM") in personal computers is dynamic RAM (DRAM). It is the RAM in laptop and workstation computers as well as some of the RAM of video game consoles. • The advantage of DRAM is its structural simplicity: only one transistor and a capacitor are required per bit, compared to four or six transistors in SRAM. • This allows DRAM to reach very high densities. Unlike flash memory, DRAM is volatile memory. It loses its data quickly when power is removed. SDRAM (Synchronous dynamic random access memory) • SDRAM is a DRAM that is synchronized with the system bus. • Classic DRAM has an asynchronous interface, which means that it responds as quickly as possible to changes in control inputs. • SDRAM has a synchronous interface, meaning that it waits for a clock signal before responding to control inputs and is therefore synchronized with the computer's system bus. • SDRAM is widely used in computers from the original SDRAM, further generations of DDR (or DDR1) and then DDR2 and DDR3. DDRRAM (Double-Data-Rate random access memory) • DDR RAM is a type of very fast computer memory. DDR RAM is based on the same architecture as SDRAM, but utilizes the clock signal differently to transfer twice the data in the same amount of time. • RAM speed works in conjunction with the front side bus (FSB) of a computer system. • The FSB is the two-way data channel that sends information from the central processing unit throughout the motherboard to the various components, including the RAM, BIOS chips, hard drives and PCI slots.

II.ROM (Read Only Memory) :- ROM is a non-volatile memory chip in which data is stored permanently and cannot be altered by the programmer. The data stored in a ROM chip can only be read and used, they cannot be changed. This is a reason why it is called read-only memory. It power is lost then information is not remove in this memory. So, we called that this memory is permanently memory. There are two types of read-only memory - manufacturer – programmed and use- programmed.


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ROM is used by computer manufactures for storing these micro programs. So, that they can’t be modify by the users. These micro programs are also called system booting program. Contain a set of start up instruction to check if the system hardware likes memory, I/O devices etc are worked properly. Important application of ROM is to store table which do not change. For example, table of trigonometric function suppose we would not store sinø values. Another example of ROM is program to control sequencing of operation of a washing machine may be store in ROM. PROM (Programmable Read Only Memory) It is possible for a user to customize a system by converting his/her programs to micro programs and storing them in a user – programmed ROM chip. ROM is commonly known as a Programmable read-only memory because a user can program it. Once the user programs are programmed to record information using a special device known as PROM – programmer. Once a chip has been programmed, the recorded information cannot be changed, i.e. the PROM becomes a ROM and it is only possible to read the stored information. PROM is also non-volatile storage, i.e. the stored information remains intact even if power is switched off. EPROM (Erasable Programmable Read Only Memory) It is possible to erase information stored and the chip can be reprogrammed to store new information using a special prom-programmer facility. Information stored in an EPROM chip is erased by exposing the chip for some time to ultraviolet light. The information is stored using ultraviolet light is called UVEPROM. EEPROM (Electrically Erasable Programmable Read Only Memory) • This memory is a part of EPROM memory. • In this type of memory the stored information is erased by using high voltage electric pulses. • The former is known as Ultra Violet EPROM – UVEPROM and latest is known as EPROM –EEPROM.


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Limitation of Primary Memory 1. Limited Capacity • Unfortunately the storage capacity of the primary storage of today’s computer is not sufficient to store the large volume of data. 2. Volatile • The primary storage is volatile and the data stored in. It is lost when the power is switched off. Slots 1. ISA SLOT • Industry Standard Architecture (ISA) is a computer bus standard for IBM PC compatible computers introduced with the IBM Personal Computer to support its Intel 8088 microprocessor's 8-bit external data bus and extended to 16 bits for the IBM Personal Computer / AT's Intel 80286 processor. • The ISA bus was further extended for use with 32-bit processors as Extended Industry Standard Architecture (EISA). • For general desktop computer use it has been supplanted by later buses such as IBM Micro Channel, VESA Local Bus, Peripheral Component Interconnect and other successors. A derivative of the AT bus structure is still used in the PC/104 bus, and internally within Super I/O chips. 2. PCI SLOT • In the back of most desktop computers are removable tabs that cover slots that have been cut into the frame. • When you remove the cover from your computer you will see that there are slots which align with the tabs. • A tab can be removed and an interface card can be installed at that location. • PCI BUSS and PCI slots are one of the types of communication formats used by desktop computers. • The main difference between PCI slot and PCI express slot is the length of the slot. • Generally PCI slot is longer than PCI express slot. The PCI express is the latest version of PCI. It is more powerful and can receive. • A PCI express slot specification for extending the internal circuitry bus that transmits data from one part of a computer to another by inserting circuit boards. It allows the expansion of a computer by inserting. • PCI slots are used for expansion cards, but not limited too. • Such as Sound cards, network interfaces devices, video cards, port enhancers and various other devices.


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3. Memory SLOT • A memory slots known as RAM slot. • A memory slot or RAM slot is what allows computer memory (RAM) chip/stick to be inserted into the computer. • Depending on the motherboard, there will usually be 2 to 4 memory slots (sometimes more on high-end motherboards) and are what determine the type of RAM used with the computer. • When buying a new computer or motherboard, pay close attention to the types of RAM the memory slots will allow to be used, so you are familiar with what type of RAM to buy for your computer. • It is also important to note how many available memory slots are available in your computer. • It is not uncommon for some computers to have all memory slots occupied, which means if you wanted to upgrade your computer memory some or all of the memory currently installed would need to be removed first. 4. SATA • Serial ATA SATA, abbreviated from Serial AT Attachment is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. • The full form of SATA is "Serial Advanced Technology Attachment," or "Serial ATA." • It is an interface used to connect ATA hard drives to a computer's motherboard. • They also use smaller, thinner cables, which allows for better airflow inside the computer. Advantages: • Sata cables are thiner so they allow for better airflow • sata cable vary faster then pata • sata cables/drives are reinforced around the connector earlier drives were fairly easy to break if you applied to much pressure as the connector is so thin. Disadvantages • When compared to the Serial Attached Small uses. • less cable length than connecting each individual device to the motherboard. • The servers can also take advantage of the speed boost because they handle. SATA hard drives sometimes require a special device driver for the computer to recognize and use the drive.


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Sockets • A socket is one endpoint of a two-way communication link between two programs running on the network. A socket is bound to a port number so that the TCP layer can identify the application that data is destined to be sent. • On the client side, if the connection is accepted, a socket is successfully created and the client can use the socket to communicate with the server. • The client and server can now communicate by writing to or reading from their sockets. • An endpoint is a combination of an IP address and a port number. Every TCP connection can be uniquely identified by its two endpoints. That way you can have multiple connections between your host and the server. Cables 1. Serial Cable • A serial cable is a cable that can be used to transfer information between two devices using serial communication. • The form of connectors depends on the particular serial port used. • A cable wired for connecting two data terminal equipments directly is known as a null modem cable. • The maximum working length of a cable varies depending on the characteristics of the transmitters and receivers, the baud rate on the cable, and the capacitance and resistance of the cable. • This cable has short transmission distance because of noise limiting the transmission of high numbers of bits per second when the cable is more than 15 meters long. • This means that the transmitting and receiving lines are referenced to ground. • It is cheap to purchase and is simple to join and connect. It is suitable for unbalanced data standards. • Only one device can be connected to the cable. 2. Parallel Cable • Computer Cable Parallel Printer cables are a reliable way to connect dot-matrix or other unidirectional printers. • This Printer Cable Male to Centronics 36 Male cables are foil shielded preventing EMI/RFI interference and ensuring accurate data transfer.


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• A parallel cable is a type of interface found on computer (personal and otherwise) for connecting various peripherals. • In computing, a parallel port is a parallel communication physical interface. • It is also known as a printer cable or Centronics cable. • The IEEE 1284 standard defines the bi-directional version of the port, which allows the transmission and reception of data bits at the same time. 3. USB Cable • A very easy way to connect two PCs is to use a USB-USB cable. • By connecting two PCs with a cable like this, you can transfer files from one PC to another, and even build a small network and share your Internet connection with a second PC. • The first thing you should be aware of is that there are several different kinds of USB-USB cables on the market.

• The one used to connect two PCs is called “bridged” (or “USB networking cable”), because it has a small electronic circuit in the middle allowing the two PCs to talk to each other. • There are called A/A USB cables that, in spite of having two standard USB connectors at each end, don’t have a bridge chip and cannot be used to connect two PCs. • In fact, if you use an A/A USB cable, you can burn the USB ports of your computers or even their power supplies. • So, these A/A USB cables are completely useless. A/B USB cables are used to connect your computer to peripherals such as printers and scanners, so they also won’t meet your needs. 4. HDMI Cable • Full form of HDMI is High-Definition Multimedia Interface. • HDMI is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device. • HDMI is a digital replacement for analog video standards.

https://en.wikipedia.org/wiki/Proprietary_hardware

https://en.wikipedia.org/wiki/Interface_(computing)

https://en.wikipedia.org/wiki/Uncompressed_video

https://en.wikipedia.org/wiki/Digital_audio

https://en.wikipedia.org/wiki/Display_controller

https://en.wikipedia.org/wiki/Visual_display_unit

https://en.wikipedia.org/wiki/Video_projector

https://en.wikipedia.org/wiki/Digital_television

https://en.wikipedia.org/wiki/Digital_audio

https://en.wikipedia.org/wiki/Analog_video


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• Several versions of HDMI have been developed and deployed since initial release of the technology but all use the same cable and connector. • Other than improved audio and video capacity, performance, resolution and color spaces.

Types of HDMI Cables:

Standard cables: They are also known as Category 1 HDMI cables. They perform at pixel speeds of 75 Mhz supporting bandwidth of about 2.23 Gbps. This is fine for carrying an uncompressed 1080i signal.

High Speed cables: They are also known as Category 2 HDMI cables. They perform at pixel speeds of 340 MHz supporting bandwidth of about 10.2 Gbps. They can handle the latest 1440p and WQXGA resolutions.

Advantages of HDMI:

¤ Higher Quality: HDMI enables loss-less transmission and better quality video at low brightness scenes at higher resolutions. So, the video quality is much better than their analog counterparts as there is no conversion involved either. High contrast details like text etc. are displayed more sharper.

¤ Intelligence: Two way communications between video sources are enabled by HDMI Interface, which enables automatic configuration (between 480p or 720p, 16:9 or 4:3 for example). So, external intervention to identify the best resolutions and audio formats is minimized. This is accomplished by using a standard known as EDID – Extended Display Identification Data.

¤ Authentication and Encryption: HDMI standard supports authentication to ensure that the devices are authorized to receive the content sent by the HDMI enabled sources. They also enable authentication to make sure that people cannot tap in to the cables to copy or pirate content sent through them.

¤ Signal Integrity: They enable digital signals to be stored, transmitted and viewed without changes from the original (unlike other media which require analog to digital conversion) and hence the signal degradation is not prominent. So, it is better to transmit HD content.

¤ Single Cable: This is truly a single cable solution as there is only a single cable that carries audio, video and control information. So, the complexity of implementing an audio video control system is lesser.

¤ Deep Colours: HDMI supports 10 bit, 12 bit and 16 bit (RGB or YCbCr) colour depths which can render over one billion colours in good detail.


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Dis-advantages of HDMI: ¤ Distance Limitations: Maximum distance for HDMI Cat1 cables is up to 35 meters (approx) for full capacity and maximum distance for HDMI Cat2 cables is up to 10 meters (approx) for full capacity. Beyond this limit, they need extenders. There are extenders like UTP cable extenders for HDMI, HDMI cable extenders, Fiber extenders for HDMI and Coaxial extenders for HDMI. Even Switches, Distribution amplifiers, audio/video processors act as repeaters. But extending HDMI cables this way has its limitations.

¤ Switching Delays: Sometimes, blank screens can be caused due to authentication delays. There can also be screen flashing errors.

¤ Field Termination: There are limitations to field terminations of HDMI cables. They cannot be easily terminated in the field like their analog counterparts.

¤ Costly: HDMI cables are more expensive (per meter) than their analog counterparts. Computer Ports 1. USB (Universal Serial Bus) Port • USB is one of the new interface technologies and it can connect computer peripherals such as mouse, keyboards, game pads and joysticks and scanners, digital cameras and printers. • USB simplifies connecting several printers to one computer. • USB ports operate at two speeds – 1.5 Mbps and 12Mbps, depending upon the speed of the device attached to the port.

• In mouse and keyboards USB use the low-band while digital cameras and scanners use the high-speed channel. • The major advantage of the USB is that devices can be hot-plugged into the system and appropriate drivers are loaded automatically. • Up to 128 devices can be connected to a single port. 2. Serial Port • It is known as asynchronous port or RS-232-C port. • The main advantage of this type of port is data sent and received over only two lines. • Therefore such type of port ideal for connections to the phone circuits, which also use two data lines. • Because of slower communications they are not suitable for printer connections.


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3. Parallel Port • A parallel port is a type of socket found on personal computers for interfacing with various peripherals. • It is known as a printer port. This type of port normally reserved for printer and some type of external storage devices.

• They carry 8 bits at a time on parallel path. Because they can transmit 8 bit (1 byte) data at a time. They are faster way to communicate with input and output devices. • One disadvantages of this port is their signal traveling capacity is less than serial port. • It makes a difference only when you want to connect a printer or other device with a very long cable. 4. PS2 Port • A type of port developed by IBM for connecting a mouse or keyboard to a PC. • The PS2 port supports a mini DIN plug containing just 6 pins. • Most PCs have a PS2 port so that the serial port can be used by another device, such as a modem. • The PS2 port is often called the mouse port.

Graphic cards • A graphics card (also known as video card) is an expansion card whose function is to generate and output images to a display. • Some video cards offer added functions, such as video capture, TV tuner adapter, ability to connect multiple monitors, and others. Most video cards all share similar components. • They include a graphics processing unit (GPU) which is a dedicated microprocessor optimized for 3D graphics rendering. • It also includes video BIOS that contain the basic program that governs the video card’s operations and provides the instructions that allow the computer and software to interface with the card. • If the video card is integrated in the motherboard, it may use the computer RAM memory. • If it is not it will have its own video memory called Video RAM. • This kind of memory can range from 128MB to 2GB. • They all have outputs such as an HD-15 connector (standard monitor cable), DVI connector, S-Video, composite video or component video.


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UPS • Uninterruptible Power Supply, a power supply that includes a battery to maintain power in the event of a power outage. • Typically, a UPS keeps a computer running for several minutes after a power outage, enabling you to save data that is in RAM and shut down the computer gracefully. • Many UPSs now offer a software component that enables you to automate backup and shut down procedures in case there's a power failure while you're away from the computer.

• There are two basic types of UPS systems: standby power systems (SPSs) and on-line UPS systems. • An SPS monitors the power line and switches to battery power as soon as it detects a problem. • The switch to battery, however, can require several milliseconds, during which time the computer is not receiving any power. • Standby Power Systems are sometimes called Line-interactive UPSes. • An on-line UPS avoids these momentary power lapses by constantly providing power from its own inverter, even when the power line is functioning properly. In general, on-line UPSs are much more expensive than SPSs. Advantages of UPS • Maintenance Of Power – The most obvious and important advantage of having a UPS power supply is the maintenance of power to all computer and electric systems in the event of a power outage. • Continuity Of Operation – The most basic feature that one UPS power supply can offer is continuity of operation. When the UPS system is plugged into an AC wall outlet, maintains a power on its batteries during normal operation. • The built – in electronics detect when there is a loss of external power and directly switch the UPS power supply from wall power to AC power that is produced through its batteries. • Line Interactive UPS – The improved form UPS, the line interactive UPS is created to clean the incoming power before sending it to the output. By adjusting its output, this line interactive UPS device can ensure that the whole electronic systems are not subject to power failure.

http://www.webopedia.com/TERM/P/power_supply.html

http://www.webopedia.com/TERM/C/computer.html

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http://www.webopedia.com/TERM/D/data.html

http://www.webopedia.com/TERM/R/RAM.html

http://www.webopedia.com/TERM/S/shut_down.html

http://www.webopedia.com/TERM/B/backup.html

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http://www.webopedia.com/TERM/O/on_line.html

http://www.webopedia.com/TERM/M/millisecond.html


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Disadvantages of UPS • StartUp Cost – Installing a UPS power supply requires a huge startup investment. • Maintenance Cost – Unfortunately, the UPS batteries do not last forever. Depending on the battery model, the UPS batteries can last about five or ten years, after which the old batteries require proper disposal, so new batteries must be purchased. • Energy Use – In order to keep the UPS batteries charged all time, the uninterruptible power supply system should draw more power than the demand of the attached equipment. All this causes enormous waste of power that is significant additional cost.

Network Card Network card is a necessary component of a computer without which a computer cannot be connected over a network. It is also known as the network adapter or Network Interface Card (NIC). Most branded computers have network card pre-installed. Network cards are of two types: Internal and External Network Cards.

Internal Network Cards

Motherboard has a slot for internal network card where it is to be inserted. Internal network cards are of two types in which the first type uses Peripheral Component Interconnect (PCI) connection, while the second type uses Industry Standard Architecture (ISA). Network cables are required to provide network access.

External Network Cards

External network cards are of two types: Wireless and USB based. Wireless network card needs to be inserted into the motherboard, however no network cable is required to connect to the network.


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Sound Card No computer is complete without sound. From listening to our favorite tunes to playing the latest, most popular video games, sound makes our computer experience fun. All this is done with a sound card. In the natural world, sound travels in waves. We refer to these waves as analog. Computers only understand digital, or 1's and 0's. Sound card technology converts analog sound, such as from a microphone or other source, to digital, then back to analog for output through speakers or headphones. While being converted to digital, sound effects or other enhancements are added before being sent to speakers. To achieve this, some cards have an ADC and a DAC chip on them. ADC stands for analog to digital converter and, as you might guess, DAC is for digital to analog converter. If they do not have these chips, a codec is used to accomplish the same thing. However, this codec is not the same as one used to convert from one file type to another, such as from mp3 to wav. So don't confuse them. Sound cards may have their own processor, called a digital signal processor (DSP) to take some of the load off the CPU. If there is no DSP, the card uses the computer's processor. They may also have their own memory.


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1. Introduction to Input Devices All i/p device is an electromechanical devices that accept data from outside world & translates them into a form the computer interpret (i.e. binary) A wide range of input devices is available today that can be broadly classified into the following

2. Types of input Devices Standard input devices Keyboard is the most commonly used input devices. They allow data entry into a computer system by pressing a set of keys. Keyboard devices can be broadly classified into two types:: 1) General Purpose. 2) Special Purpose. General purpose keyboard General purpose keyboards are standard keyboards used with most computer systems. They are called general purpose because they have enough keys to make them useful for any type of application.

2.1 Input Devices Topic Covered

1. Introduction 2. Types of input Devices

Keyboard, Mouse, Trackball, Glide - pad, Game Devices Joystick, etc. Light pen, Touch Screen, Digitizers and Graphic Table, Mic Camera, POS Terminal

3. MIDI (Musical Instrument Digital Interface) 4. Types of Scanners

OCR, OMR, MICR, OBR

Chapter 2


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They are design to meet the data entry requirements of a very wide range of computer users. The most popular general – purpose keyboards used today are the 101 – keys QWERTY keyboard. It was introduced and promoted by IBM for use with IBM PCs. The keys of a QWERTY keyboard are grouped into the following functional groups to make the keyboard easier and more comfortable to use :: Key-Board Alphanumeric keys:- The alphanumeric keys contain the number 0-9 and several special characters like ?,/,$,&,@,etc. Numeric keys:- The numeric keypad is a set of keys that looks like an adding machine with its ten digits (0-9) and mathematical operators (+,-,*,.,/).

It is usually located on the right side of the keyboard. Arrow keys:- Arrow keys are a set of four keys up, down, left and right. They are also called “cursor – control” or “cursor – movement” keys. Special function key:- The keyboard also has a set of special function keys. Some of the most important keys are Enter, Shift, Ctrl, Alt, Backspace, Tab, Caps Lock, Num Lock, Home, End, Delete, Page Up, Page Down, Insert, Escape, Spacebar, Print screen, etc. Other function key:- The other function keys are known as user – programmable function keys they are contains F1, F2, F3 and so on. Special purpose keyboard Special purpose keyboard have special function for faster data entry & rapid interaction with computer. For example, instead of typing the name and price of a purchased item.

Like Veg. Pizza, the operator need only press the key labeled “Veg. Pizza” and the system automatically prints the name and price of the item from an internally store database. This application requires a special purpose keyboard for rapid data entry and fasteroperation.


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Advantages Reliable for data input of text and numbers. Usually supplied with a computer so no additional cost. Specialized keyboards are available. Disadvantage Users may be slow for not very accurate typists. Slow for accessing menus etc. and difficult to use if you want to move objects around the screen. Difficult for people unable to use keyboards through paralysis or muscular disorder. Pointing Devices

Mouse:- It is a small hand held device which fit into the user palm. It rolls on small bearing and has one or more button on top. When a user rolls the mouse across a flat surface such as on top of the table cursor moves on the side where mouse moves.

Cursor has variety of symbols such as an arrow, pointing finger, etc. Techniques of mouse 1. Point:- To point the menu item on top of the menu for selecting it using left mouse button. 2. Click:- To press and release mouse once to select the menu item using left key of mouse. To press and release once to call the pop up option menu using right key of mouse Usually depends on the software where the right click is used. 3. Double – click:- Using left key of mouse to press and release left button 2 times rapid to execute the selected icon.


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Using right key it depend on the software where the double right click is used. 4. Simultaneous – click:- To simultaneous – click means to press and release both the left and right mouse buttons simultaneously. It is used by some software packages to give added functionality to the mouse. 5. Drag:- Press and hold the left button. For example, 1) To change the location or position of the icon. 2) To draw object in some software such as Paint. 3) To select the paragraph to copy or for selection to change style of font or size.

Types of Mouse:- There are 4 type of different categories of mouse 1. Mechanical and Optical Mouse:-Mechanical mouse:- A mechanical mouse has a ball inside it. The ball rolls due to surface when the mouse is moved on a flat surface. On both sides of the ball at a 90-degree angle from each other there are two small wheels that spin to match the speed of the ball.

Each wheel of the mouse is connected to a sensor. The mouse ball rolls when the mouse is moved, the sensors detect how much each wheel spins and send this information to the computer in the form of changes to the current position of the graphics cursor on the screen. The mouse ball rolls when the mouse is moved, the sensors detect how much each wheel spins and send this information to the computer in the form of changes to the current position of the graphics cursor on the screen. Optical mouse:- An optical mouse has no mechanical parts like the ball and wheels. It has a built-in photo-detector. This type of mouse comes with a special pad with gridlines printed on it. For moving the graphics cursor on the screen the mouse has to be moved on the special pad.


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2. One, Two and Three Buttons Mouse:- A mouse can have one, two or three buttons. Programs are designed to use only a single button. In two or three button mouse, the leftmost button is the main button that allows most mouse operations because most people are right-handed and use their right-index finger to click the main button. 3. Serial and Bus mouse:- A serial mouse is one, which is designed to plug into a serial port. This type of mouse does not require a special electronic card for connecting the mouse to the computer system. A bus mouse is one that requires a special electronic card that provides a special port just for the mouse for connecting to the computer system. The special electronic card is fitted into one of the expansion slot inside the computer. A bus mouse occupies one of the expansion slot where a serial mouse does not need any expansion slot. 4. Wired and Cordless Mouse:- A wired mouse connected to the computer system with a small card. On the other hand, a cordless mouse is not connected to the computer system. It communicates with the computer system with the help of a special controller that operates by transmitting a low-intensity radio or infrared signal. A cordless mouse is more expensive than a wired mouse, it allows easier movements of the mouse Uses: Movement - controlling a screen pointer Buttons - selecting items / menus etc. Advantages: Ideal for use with desktop computers. Usually supplied with a computer so no additional cost. All computer users tend to be familiar with using them. Disadvantages: They need a flat space close to the computer. The mouse cannot easily be used with laptop, notebook or palmtop computers. (These need a tracker ball or a touch sensitive pad called a touch pad).


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Track Ball

It is an another pointing device. It uses the spherical ball which is rolled by the palm of the hand. The spherical ball is moved on top from thumb or finger and relative the cursor moves in screen. It does not require much space to use it and it can be placed on any type of surface.

Advantages: Ideal for use where flat space close to the computer is limited. Can be useful with laptops as they can be built into the computer keyboard or clipped on. Disadvantages: Not supplied as standard so an additional cost and users have to learn how to use them.

Glide Pad A touch-sensitive pad about 2 x 2 that will track the touch of a finger. It is not a pressure sensor, so there is no need to press down, only to touch. This device acts like a mouse for pointing, and you can tap quickly on the pad to mimic a click

Joystick A lever that moves in all directions and controls the movement of a pointer or some other display symbol. A joystick is similar to a mouse, except that with a mouse the cursor stops moving as soon as you stop moving the mouse. With a joystick, the pointer continues moving in the direction the joystick is pointing. To stop the pointer, you must return the joystick to its upright position. Most joysticks include two buttons called triggers.


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Light Pen When the light is sensed the corresponding information is generated and the position of the light pen is located. It can be used to draw object , point ,etc Light pen does not have any tracking hardware to make use of light pen as a ‘position’ device a tracking program must be loaded in computer.

Touch Screen

A touch screen is an input device that allows users to operate a PC by simply touching the display screen. Touch screen is designed by different technologies 1) By use of the optical sensor:- optical sensor can sense the touch of the user when input is made with the finger. 2) Pressure sensitive monitors:- which has sensor to measure the weight of monitor when user touches the screen the weight and force information is transferred to sensor and the sensor allow the device to detect the touch location. Some time user need to supply force on the screen to select the menu. 3) The display screen:- It has a sensitive glass overlay placed on it and we could give the desired input by touching it. A touch screen is based on CRT (Cathode Ray Tube) technology, which accepts direct onscreen input. The ability for direct onscreen input is facilitated by an external (light pen) or an internal device (touch overlay and controller) Main touch screen components: Touch sensor Controller Software driver TOUCH SENSOR A touch screen sensor is a clear glass panel with a touch responsive surface which is placed over a display screen so that the responsive area of the panel covers the viewable area of the display screen.

It is called light pen, because its construction is similar to a pen and senses light. Construction of light pen is very simple. It has a photo cell which senses light of screen and converts into electrical signal. Using of light pen screen is refreshed every time which sense the change in light i.e. change in brightness of the screen.


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The sensor generally has an electrical current or signal going through it and touching the screen causes a voltage or signal change. This voltage change is used to determine the location of the touch to the screen

CONTROLLER The controller is a small PC card that connects between the touch sensor and the PC. It takes information from the touch sensor and translates it into information that PC can understand.

SOFTWARE DRIVER The driver is software that allows the touch screen and computer to work together. It tells the operating system how to interpret the touch event information that is sent from the controller. Most touch screen drivers today are a mouse-emulation type driver. This makes touching the screen the same as clicking your mouse at the same location on the screen. Use of Touch Screen Public Information Displays::: Tourism displays, Trade show display Customer Self-Services: Stores, Restaurants, ATMs, Airline ticket terminals and Transportation hubs. More uses... Computerized gaming, Student Registration systems, Multimedia software, scientific applications etc. Information counters : For public counter such as in bus stands, railways station, some museums, airport, departmental store, malls for the location of goods, rest room, to show way to customer and for attraction in shopping mall. Other Touch screen Technology Resistive touch screen Capacitive touch screen Infrared touch screen Surface acoustic wave (SAW) touch screen


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1. Resistive Touch screen Resistive Touch screens consist of a glass or acrylic panel that is coated with electrically conductive and resistive layers made with Indium Tin Oxide (ITO). The thin layers are separated by invisible spacers. Characteristics of Resistive Touch screen 1. Cost effective solutions 2. Activated by a stylus, a finger or gloved hand 3. Not affected by dirt, dust, water, or light 4. 75%~85% clarify 5. resistive layers can be damaged by a very sharp object 2. Capacitive Touch screen Capacitive touch screen describe a two parts 1. Projected – capacitive touch screen 2. Surface – capacitive touch screen Projected – capacitive touch screen:- Projected capacitive touch screens have front and back protective glass providing optical and strength enhancement options. Its middle layer consists of a laminated sensor grid of micro-fine wires, and optical enhancement options. During a touch, capacitance forms between the finger and the sensor grid. The embedded serial controller in the touch screen calculates touch location coordinates and transmits them to the computer for processing. Surface – capacitive touch screen:- Surface capacitive technology consists of a conductive coating on a glass panel. Electrical rays around the panel’s edge evenly distribute a low voltage across the conductive layer, creating a uniform electric field. A human body is an electric conductor, so when you touch the screen with a finger, a slight amount of current is drawn, creating a voltage drop. Characteristics of Capacitive touch screen 1. Faster and more responsive. 2. Superior optical clarity, brighter display and less surface reflection. 3. Must be touched by finger, will not work with any non-conductive input


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3. Infrared touch screen Infrared (IR) technology relies on the interruption of an IR light grid in front of the display screen. The touch frame contains a row of IR-light emitting diode (LEDs) and photo transistors, each mounted on two opposite sides to create a grid of invisible infrared light. The IR controller sequentially pulses the LEDs to create a grid of IR light beams. When a stylus, such as a finger, enters the grid, it obstructs the beams. One or more photo transistors from each axis detect the absence of light and transmit a signal that identifies the x and y coordinates. Characteristics of Infrared touch screen 1. Clear as glass, improves reading ability. 2. Most durable surface. 4. Surface Acoustic Wave (SAW) Touch Screen Surface waves are readily absorbed when a soft object such as a fingertip touches the substrate. The touch screen controller sends an electrical signal to the transmitting transducer, which converts the signal into ultrasonic waves within the glass. When you touch the screen, you absorb a portion of the wave traveling across it. The received signal is then compared to the stored digital map, the change recognized, and a coordinate calculate. Characteristics of SAW touch screen 1. Durable glass construction 2. High optical clarity 3. Activated by a finger, gloved hand or soft tip 4. Not completely sealable, can be affected by large amounts of dirt, dust, and / or water in the environment Finally though the touch screen technology contains some limitations it’s very user friendly, fast, accurate, easy for the use & fun. It has been widely accepted and now by just modifying a little it can replace the mouse and key board completely in near future.


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Graphics tablet

A graphics tablet (also digitizer, digitizing tablet, graphics pad, drawing tablet or pen tablet) is a computer input device that enables a user to hand-draw images and graphics, similar to the way a person draws images with a pencil and paper. These tablets may also be used to capture data or handwritten signatures. It can also be used to trace an image from a piece of paper which is taped or otherwise secured to the surface. Capturing data in this way, either by tracing or entering the corners of linear poly-lines or shapes is called digitizing. A graphics tablet (also called pen pad or digitizer) consists of a flat surface upon which the user may "draw" or trace an image using an attached stylus, a pen-like drawing apparatus. The image generally does not appear on the tablet itself but, rather, is displayed on the computer monitor. Some tablets, however, come as a functioning secondary computer screen that you can interact with images directly by using the stylus.

Digitizer A digitizer is an input device, which is used for converting (digitizing) pictures, maps and drawings into digital form for storage -in computers. For example, the x and y coordinates of points in a drawing mat be stored in digital form. This enables re-creation of the drawing from the stored information, and easy incorporation of changes in the drawing, as and when required.

A digitizer consists of a digitizing tablet (also known as graphics tablet) associated with a stylus. The digitizing tablet is a flat surface, which contains hundreds of fine copper wires forming a grid. Each copper wire receives electric pulses. The digitizing tablet can be spread over a working table, and is connected to a computer. The stylus is like a pen, or a lens-like cursor with a cross hair and button. The stylus is connected to the tablet, and can be pressed down at a point on the tablet to input the (x, y) coordinates of the point.


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When the stylus is moved on the tablet, the cursor on the computer's screen moves simultaneously to a corresponding position on the screen to provide visual feedback to the operator. Digitizers are commonly used in the area of Computer Aided Design (CAD) by architects and engineers to design cars, buildings, medical devices, robots, mechanical parts, etc. They are also used in the area of Geographical Information System (GIS) for digitizing of maps, which are available in paper form.

Microphone This is used for the input of sound which is then digitized by the computer. The digital audio can be saved for playback later on. The digital audio can also be used with voice-recognition software to control hardware, navigate a menu or input text into a word processor. Voice recognition can also be used in security systems. Advantages: Voice recognition software can be used to convert your voice into text or to control menu options on a phone system. Disadvantages: Stored audio files can take up a lot of memory. Voice commands can be difficult to recognize by the software.

Digital camera These are used to take photographs like a normal camera but produce digital images instead of using film. The light passing through the lens is digitized by special light sensitive sensors. The image is stored on memory chips in the camera and can then be transferred to a computer. The resolution of such cameras is increasing rapidly and professional models have become standard in photo-journalism. Images are usually compressed as jpeg's to save memory. Removable memory card Advanced models have removable memory cards to increase the camera's storage capacity. Images can be transferred to a computer by cables or memory card readers.


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POS (Point Of Sale)

A point-of-sale display (POS) is a specialized form of sales promotion that is found near, on, or next to a checkout counter (the "point of sale"). They are intended to draw the customers' attention to products, which may be new products, or on special offer, and are also used to promote special events, e.g. seasonal or holiday-time sales. POS displays can include shelf edging, dummy packs, display packs, display stands, mobiles, posters, and banners. POS can also refer to systems used to record transactions between the customer and the commerce.

Computer terminal A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system. Early terminals were inexpensive devices but very slow compared to punched cards or paper tape for input, but as the technology improved and video displays were introduced, terminals pushed these older forms of interaction from the industry. A related development was timesharing systems, which evolved in parallel and made up for any inefficiencies of the user's typing ability with the ability to support multiple users on the same machine, each at their own terminal. The function of a terminal is confined to display and input of data; a device with significant local programmable data processing capability may be called a "smart terminal" or fat client. A terminal that depends on the host computer for its processing power is called a dumb terminal or thin client. A personal computer can run software that emulates the function of a terminal, sometimes allowing concurrent use of local programs and access to a distant terminal host system.

MIDI(Musical Instrument Digital Interface):- Musical Instrument Digital Interface (MIDI) enables musical hardware, such as keyboards and drum machines, to communicate with your computer. Rather than playing actual sounds into a computer, MIDI plays 'messages' containing information like the note played and how long and hard it was played.

MIDI is also used to edit parameters and effects, such as filters.


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Features of MIDI A new version of MIDI tentatively called "HD Protocol" or "High-Definition Protocol" has been under discussion since 2005, when it was announced as "HD-MIDI". This new standard offers full backward compatibility with MIDI 1.0 and is intended to support higher-speed transports, allow plug-and-play device discovery and enumeration, and provide greater data range and resolution. The numbers of channels and controllers are to be increased, new kinds of events are to be added, and messages are to be simplified. Entirely new kinds of events will be supported. Special input devices Scanner A scanner is an input device that translates paper documents into an electronic format that can be stored in a computer. The input documents may be typed text, pictures, graphics or even handwritten material. The scanner treats the document as if it is drawn on graph sheet.

An intersection of horizontal & vertical line of a graph are called grid point. If there is dark spot at the grid point it is represented by ‘1’ otherwise ‘0’ This representation is called bit map representation of image. Each bit in the representation of image is called “Pixel”. Scanner having 300 to 600 grid points per inch are common. Scanners come in various shapes and sizes.

3. The types of scanner 1. Flat Bed Scanner 2. Hand Held scanner 3. Optical Scanner

i.Optical Mark Reader ii.Optical Char Reader

iii.Optical Barcode Reader iv.Magnetic Ink Character Recognition

1. Flat Bed Scanners

https://en.wikipedia.org/wiki/Backward_compatibility


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A Flatbed scanner is usually composed of glass plate which you can lid documents to be scanned. Flatbed scanners are effectively useful to scan documents. The document to be scanned is placed upside down. The light source is situated below the glass plate and move horizontally from left to right when activated. After scanning one line it moves to the next line to scan and this process continue. It takes about 20 seconds to scan a document of size 21 cm X 28 cm.

2. Hand-held Scanner Hand-held scanner scan a document at a time a scanner is slowly dragged from one end of the document to its other end with its light on. The scanner has to be dragged very steadily and carefully over the document; otherwise the conversion of the document into its equivalent bit map will not be correct. They are usually used to read the barcodes & text in libraries and departmental stores. It contains the set of LED. It is cheaper than flat bed scanner. I) Optical Mark Readers (OMR) These scanners are capable of recognizing a pre specified type of mark made by pencil or pen. The use of OMR is not limited to the grading of objective tests. But it is useful to any input data that is of a choice or selection nature can be recorded for OMR input. OMR Software is a computer software application that makes OMR possible using a desktop computer. Advantages: Very cheap Checking of papers made fast, accurate and without corruption. Disadvantages:: Can’t read character Erasing or cancellation not possible The main disadvantage is need for good quality expensive paper.


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II) Optical Character Readers (OCR) These devices are capable of detecting alphabetic and numeric characters printed on paper. An OCR device will transform the hand written text into the text in the computer. Some advanced OCR systems have the ability to recognize graphics and charts. If the characters are typewritten, they must be typed using a special type font called an OCR font. The standard fonts used are OCR-A (American standard) and OCR- B (European standard). Some OCR devices can also accept computer print-out and complete pages of typed text. Advantages: Speed up data input. OCR devices can now accept a wide range of fonts, using ordinary (simple) inks. Disadvantages:: OCR devices are expensive and so used only for large- volume processing applications. Characters can be scanned properly only if they are standard size. Roughly handled and dusty papers can not be scanned with accuracy. III) Optical Barcode Reader (OBR) As the name suggests, an Optical Barcode Reader is used to read printed barcodes. Bar codes represent alphanumeric data by a combination of adjacent vertical lines by varying their width and the spacing between them.

A barcode reader is uses a laser – beam scanning technology. Different barcodes having different patterns of bars reflect the beam in different ways, which is sensed by a light – sensitive detector. It a type of hand held scanners. IV) Magnetic Ink Character Recognition (MICR)


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It is a character recognition technology mainly used in banking sector. It allows the computers to read information like account numbers from printed documents. In MICR, the characters are printed on documents using special magnetic ink.

These characters when passed through the MICR device are identified by their magnetic field. Advantages:: Even roughly handled, folded, smeared can still be read with a high degree of accuracy. Speed up data input for the banking industry because check can be directly fed into the input device. Disadvantages:: No alphabets can be used. Special ink is required, hence expensive.

2.2 Output Devices


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4. Introduction of Output Device

An output device is an electromechanical device that accepts data from a computer and translates them into a form suitable for use by the outside world. A wide range of output devices is available today that can be broadly classified into the following categories::

Topic Covered 5. Introduction 6. Types of Output Devices

i. CRT Display Monitor Monitor

ii. Non CRT Display Units LCD ,LED, Plasma Displays

7. Types of Printers i. Impact Printer and Types

Dot Matrix Printer, Daisy Wheel printer, Chain Printer, Drum Printer, Band printer, etc.

ii. Non Impact Printers and types Ink Jet Printer, Laser Printer, etc.

8. Plotters Types of Plotters

9. Other Devices Fascimile(FAX) OLED (Organic LED) Headphone SGD (Speech Generating Device) COM (Computer Output Microfilm) Google Glass


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5. Types of Output Devices

MONITOR (VDU):- Monitors are by far the most popular output devices used today for producing softcopy output. They display the generated output in on the screen. Monitor is known as VDU (Video Display Unit) or screen. Monitors are available in various size like 14, 17 and 21 each, etc. They are two basic types of monitors used today 1) CRT (Cathode – Ray – Tube) and 2) Flat – Panel display The CRT monitors look like a television and are used with non-portable computer systems. The Flat – panel monitors are thinner and lighter and commonly used with portable computer systems like notebooks, LCD computers.

CATHODE – RAY – TUBE (CRT) MONITORS CRT display is the most common type of computer displays. The main component inside a monitor is a picture tube or CRT. CRT is one type of glass tube enclosing a source of electrons, an electrode, focusing system, a horizontal and vertical deflection system, and a phosphor coated screen which glows when an electron beam strikes it. The screen’s phosphor coating is organized into a grid of dots called “Pixels”. CRT based on the resolution and number of colors supported several standards for color monitors have evolved. The four most popular standards are:: 1. CGA – Color Graphics Adapter: - It has a low resolution of 320 by 200 and supports up to 16 colors. 2. EGA – Extended Graphics Array: - It has a resolution of 640 by 350 and supports up to 16 colors. 3. VGA – Video Graphics Array: - It has a resolution of 640 by 480 and supports up to 256 colors. 4. Super VGA: - It provides resolution from 800 by 600 to 1280 by 1024 and supports 256 or more colors. Now a day’s all modern personal computers used VGA and SVGA adapter.

FLAT – PANEL MONITOR (LCD, PLASMA DISPLAY PANELS)


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Flat – panel monitors are work same like a CRT monitors but they look very different of them. Mainly flat- panel monitors are contains two parts:: 1. LCD Monitors 2. Plasma Display Panels (PDPs)

1. LCD Monitors:- A flat panel monitor (LCD) is only about one inch thick, is light in weight and consumes less electricity as compared to a CRT monitors. These features make a flat panel monitor most suitable for use with portable computer system such as a laptop computer and notebook computers. A portable computer must be compact in size, light in weight and should consume less power so that it can be operated for longer durations with battery at places where there is no power point in a traveling. This requirements make a CRT monitor unsuitable for these systems because of its large size, heavy weight and more power requirement. The display technologies used by flat panel monitors include Liquid Crystal Display (LCD), Electro Luminescent Display (ELD) and Gas Plasma Display (GPD). LCD monitors use a special kind of liquid crystals to display images on the screen. One problem with these monitors is that they are hard to read under certain lighting condition. This is because unlike the phosphors used in CRT monitors, the liquid crystals do not glow when charged, so there is not enough contrast between the images and their background to make them clearly readable under all lighting conditions. To take care of this problem some LCD put a light source behind the screen. One problem with these monitors are hard to read under certain lighting condition because unlike phosphors used in CRT monitors, liquid crystals do not glow when charged .so it is not readable in all lighting condition.

2. Plasma Display Panel (PDP):- A plasma display panel is a type of flat panel display used for large TV display. Many tiny cells located between two plates of glass hold an mixture of neon and xenon gases. The gas in the cells is electrically turned into a plasma which then excites phosphors to emit light. The xenon and neon gas in plasma television is contained in hundreds of tiny cells positioned between two plates of glass.


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Long electrodes are also sandwiched between the glass plates, in front of and behind the cells. Control circuitry charges the electrodes that cross paths at a cell, creating a voltage difference between front and back and causing the gas to ionize and form plasma. In color panel the back of each cell is coated with a phosphor. Every pixel is made up of separate sub pixel cells, each with different colored phosphors. One sub pixel has a red light phosphor, one has green light phosphor, and one has blue light phosphor. These colors blend together to create the overall color of pixel. Characteristics of PDP:- Plasma has wide color of range, and can be produced in fairly large sizes up to 103 inches. Display panel is only about 2.5 inches thick, while the total thickness is less than 4 inches. The lifetime of plasma is estimated 60,000 hours.

3. Light - Emitting Diode (LED) :- An LED display is a flat panel display, which uses light-emitting diodes as a video display. An LED panel is a small display, or a component of a larger display. They are typically used outdoors in store signs and billboards, and in recent years have also become commonly used in destination signs on public transport vehicles or even as part of transparent glass area. LED panels are sometimes used as form of lighting, for the purpose of general illumination, task lighting, or even stage lighting rather than display. There are two types of LED panels: conventional (using discrete LEDs) and surface-mounted device (SMD) panels. Most outdoor screens and some indoor screens are built around discrete LEDs, also known as individually mounted LEDs. A cluster of red, green, and blue diodes is driven together to form a full-color pixel, usually square in shape. These pixels are spaced evenly apart and are measured from center to center for absolute pixel resolution. The largest LED television in the world is the Center Hung Video Display at Cowboys Stadium, which is 160 × 72 ft (49 × 22 m), 11,520 square feet (1,070 m2). The first true all-LED flat panel television screen was possibly developed, demonstrated and documented by James P. Mitchell in 1977.


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The 2011 UEFA Champions League Final match between Manchester United and Barcelona was broadcast live in 3D format in Gothenburg (Sweden), on an EKTA screen. LED text displays refer to types that are specialized and limited to display of alpha-numeric characters. Most types display either one character or a group of characters. One character is generally displayed by a matrix of LEDs, or by a matrix of segments.

Printers:- Printers are the most commonly used output devices that can be found in almost all computer centers. They are the primary output devices used to prepare permanent documents in human readable form. There is different type of printer. It is depending on speed and printing approach. Printers are classified as character printer, line printer and page printer.

6. Types of Printers The various types of printers are used today. Mainly the printers had two types.

Impact Printer:- 1) Dot – Matrix Printer:-

Impact Printer

- Dot - Matrix Printer

- Daisy Wheel Printer

- Drum Printer

- Chain Printer

- Inkjet Printer

- Laser Printer

Printers

Non- Impact Printer


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Dot – Matrix printer is a one type of impact printer because they print by hammering the pins on the inked ribbon to leave ink impressions on the paper. They are character printers that from characters and all kinds of images as a pattern of dots.

A dot – matrix printer has a print head that can move horizontally across the paper. The print head contains an array of pins, which can be activated independent of each other to extend and strike against an inked ribbon to form a pattern of dots on the paper. For faster printing, many dot matrix printers are designed to print both while the print head moves from left to right and while it moves from right to left an return. All characters are formed by 5 horizontal and 7 vertical dots. So a pattern is called 5 by 7 matrixes. It having a printing speed is between 30 to 600 characters per second.. The quality of the printed output is directly proportional to density of the dots on the matrix. This type of printers are very cheaper then other printers. Dot – matrix printers are noisy as compared to non-impact printers. 2) Daisy – Wheel Printer:- It is a one type of Impact printer. We can print a document using a print wheel so we can know this type of printer as a Daisy – Wheel printer. Each panel of the daisy wheel has a fixed size character embossed on it. When the desired character moves to the correct position, a print hammer strikes to produce the output. This type of printer’s print quality is good.

3) Drum Printer:- A drum printer is a part of Impact printer. It is consists of a solid, cylindrical drum that has raise characters in band on its surface. There are many bands as there are printing positions. Each band contains all the possible characters.

The drum rotates at a rapid speed. For each possible print position there is a print hammer located behind the paper.


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These hammers strike the paper along with the inked ribbon against the proper character on the drum. These means that all characters on the line are not printed at exactly the same time but the time required to print the entire line is fast so we can call this type of printer as a Line printer too The speeds of drum printers are in the range of 300 to 2000 lines per minute. 4) Chain Printer:- It is an Impact Printer and they use a rapidly moving chain called a print chain. Each link of the chain is a character font. There is a print hammer located behind the paper.

As the print chain rotates, the properly timed print hammers strike the paper, along with the ink ribbon, against the proper character on the chain. Speed of chain printers ranges from 400 to 2500 characters per minute. 5) Band Printer:- It is a one type of Impact printer. Band printer uses a metal band as its printing mechanism. The Band contains a fixed set of embossed characters that can only be changed by replacing the band. The Band spins horizontally around a set of hammers, one for each print column. When the required character in the band has revolved to the selected print column, the hammer pushes the paper into the ribbon and against the embossed image of the letter, digit or symbol. Band printer can print up to approximately 2,000 Line per Minute (lpm). Non - Impact Printer:- 1) Inkjet Printer:- Inkjet printer is a one type of non-impact printer. Inkjet printers are character printers that from characters and all kinds of images by spraying small drop of ink on to the paper. The print head of an inkjet printer contains up to 64 tiny nozzles, which can be selectively heated up in a few microsecond by an integrated circuit register.

It is produce a high quality output than dot-matrix printer because they from characters by very tiny ink dots.


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A high- resolution inject printer has 64 nozzles within height of 7mm providing print resolution of around 360 dots per inch. Inkjet printers produce printed output as patterns of tiny dots, they can print any shape of character that a programmer can describe. Inkjet printers are slower then dot-matrix printers with speeds usually ranging between 40 to 300 characters per second. Inkjet printer is more expensive that a dot-matrix printer 2) Laser Printer:- Laser printer is a one type of Non-impact printer. Laser printers are page printers that print one page at a time. The main components of a laser printer are a laser beam source, a multi-side mirror, a photoconductive drum and toner.

To print a page of output the laser beam is focused on the electro statically charged drum by the spinning multisided mirror. The mirror focused on the laser beam on the surface of the drum in such a manner that it created the patterns of characters/ images to be printed on the page. As the drum is photoconductive, a difference in electric charge is created on those parts of the drum surface that are exposing to the laser beam. The toner is then permanently fused on the paper with heat and pressure to generate the printed output. The drum is then rotated ad cleaned with a rubber blade to remove the toner sticking to its surface to prepare the drum for the next page printing. Laser printers produce very high quality output because they from characters by very tiny ink particles. The most common laser printers have resolutions of 600 dpi (dots per inch) where as some high-end laser have resolutions of 1200 dpi. Laser printers are faster then other printers. Low speed laser printers can print 4 to 12 pages per minute. Very high-speed laser printers are also available which can print 500 to 1000 pages per minute. That is fast enough to print this entire book in about one minute. Because of their better print quality and printing speed, Laser printers are more expensive than other printers. Difference between Impact and Non- Impact Printer Impact Printer Non-Impact Printer It is a noisy printer It is a silent printer.


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It prints a document by hammering on a paper.

It prints a document by spring on a paper.

This type of printers is very cheap. The types of printers are very costly. Dot-matrix, Drum, Chain, Daisy wheel printers are known as impact printers.

Inkjet and Laser printers are known as non – impact printers.

In this type of printers are used ink ribbons.

This type of printers are doesn’t use any ribbon.

7. Plotters Many Engineers design applications, like architectural plan of a building, design mechanical components of an aircraft or a car etc. They require high-quality, perfectly-proportioned graphic output on large sheers. The various types of printers are not suitable for meeting this output requirement of such applications. A special type of output device, called plotters, is used for this purpose. Plotters are ideal output device for architects, engineers, city planners, and others who need to routinely generate high-precision, hard – copy, graphic output of widely varying sizes. Mainly plotters are two types:: 1. Drum Plotter 2. Flatbed Plotter

1) Drum Plotter:- In a drum plotter the paper, on which the design has to be made is placed over a. drum, which can rotate in both clockwise and anti-clockwise directions to produce vertical motion. The mechanism also consists of one or more penholders mounted perpendicular to the drum’s surface.

The pen (s) clamped in the holder (s) can move left to right or right to left to produce horizontal motion. The movement, of the drum and the pen (s) are controlled by the graph-plotting program. That is, under computer control, the drum and the pen (s) move simultaneously to draw the designs and graphs on the sheet placed on the drum. The plotter can-also annotate the designs and graphs so drawn by using the pen to draw characters of various sizes.


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Since each pen is program selectable, pens having ink of different colors can be mounted in different holders to produce multi-colored designs.

2) Flatbed Plotter:- A flatbed plotter plots a design or graph on a sheet of paper, which that is spread and fixed over a rectangular flatbed table. In this type of plotter, normally the paper does not move, and the pen holding mechanism is designed to provide all types of motions necessary to draw complex designs and graphs.

That is, under computer control, the pen (s) move in the required manner to draw the designs and graphs on the sheet placed on the flatbed table. The plotter can also annotate the designs and graphs so drawn by using the pen to draw characters of various sizes. Each pen is program selectable, pen, having ink of different colors can be mounted in different holders to multi-colored designs. The plot size is restricted by the area of the bed. Some may be as small as 44 size (8”*11” page), while some very large beds used in tire design of cars, ships, aircrafts, buildings, highways, etc. can be up to 20 ft. by 50 ft. Some plotters are also designed to etch plastic or metal plates. In this case, the plastic or metal sheet is spread on the bed, and the drawing pen has a sharp-edged needle.

Speaker An electro-acoustic transducer that converts electrical signals into sounds loud enough to be heard at a distance. Computer speakers, or multimedia speakers, are external speakers and are usually equipped with a male-end phone plug for computer sound cards; however, there are some speaker that have female RCA (phono) plug ports, and some people link computer sound cards to nearby stereo systems. Computer speakers are usually a simplified stereo system without a radio or other media sources built in. The simplest computer speakers come with computers. There are advanced forms of computer speakers that have graphic equalization features (bass, treble, etc.) for dynamic audio flexibility.

8. Other Devices

Fascimile (FAX):-


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Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer or other output device.

The original document is scanned with a fax machine (or a telecopier), which processes the contents (text or images) as a single fixed graphic image, converting it into a bitmap, and then transmitting it through the telephone system in the form of audio-frequency tones. The receiving fax machine interprets the tones and reconstructs the image, printing a paper copy. Early systems used direct conversions of image darkness to audio tone in a continuous or analog manner. Since the 1980s, most machines modulate the transmitted audio frequencies using a digital representation of the page which is compressed to quickly transmit areas which are all-white or all-black. In many corporate environments, freestanding fax machines have been replaced by fax servers and other computerized systems capable of receiving and storing incoming faxes electronically, and then routing them to users on paper or via an email (which may be secured). Such systems have the advantage of reducing costs by eliminating unnecessary printouts and reducing the number of inbound analog phone lines needed by an office. Characteristics of FAX:-

1. Printing process Fax machines from the 1970s to the 1990s often used direct thermal printers with rolls of thermal paper as their printing technology, but since the mid-1990s there has been a transition towards plain-paper faxes:- thermal transfer printers, inkjet printers and laser printers.

2. Stroke speed Stroke speed in facsimile systems is the rate at which a fixed line perpendicular to the direction of scanning is crossed in one direction by a scanning or recording spot. Stroke speed is usually expressed as a number of strokes per minute. When the fax system scans in both directions, the stroke speed is twice this number.

https://en.wikipedia.org/wiki/Facsimile

https://en.wikipedia.org/wiki/Bitmap

https://en.wikipedia.org/wiki/Fax_server

https://en.wikipedia.org/wiki/Email

https://en.wikipedia.org/wiki/Thermal_printer

https://en.wikipedia.org/wiki/Thermal_transfer_printer

https://en.wikipedia.org/wiki/Inkjet_printer

https://en.wikipedia.org/wiki/Image_scanning

https://en.wikipedia.org/w/index.php?title=Recording_spot&action=edit&redlink=1


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In most conventional 20th century mechanical systems, the stroke speed is equivalent to drum speed. 3. Fax paper As a precaution, thermal fax paper is typically not accepted in archives or as documentary evidence in some courts of law unless photocopied. This is because the image-forming coating is eradicable and brittle, and it tends to detach from the medium after a long time in storage.

Advantages of Fax 1. Speedy Transmission: Fax enables transmission of message, data, diagram, sketches and drawing with exceptionally high speed. 2. Accuracy of Information: It helps to send written information to any place within or outside the country accurately. 3. Legal value: Fax provides a written record of the transmitted message and it can be used as a document in a count of law. 4. Overcoming barrier: Fax can be sent to any point where there is availability of telecommunication system. There is no hassle to carry the document physically. 5. Confirmation of Receiving: Fax provides confirmation for the data or information received by the user.

Disadvantages of Fax 1. Less Privacy: Fax has less privacy as the transmitted data can be handled by anyone who is beside the fax machine. 2. Hazy information: Fax may send hazy information due to problem with the machine and therefore purpose of fastest delivery will be unsuccessful. 3. Dependency on telephonic system: Fax uses telephonic system to transmit data and if such system is down then sending of data and information face problem

OLED (Organic LED):-

Organic light emitting diodes are a relatively new technology for solid state light sources.

A typical OLED consists of two organic layers (electron and hole transport layers), embedded between two electrodes. The top electrode is usually a metallic mirror with high reflectivity and the bottom electrode a transparent ITO layer on top of the glass substrate. When a voltage is applied to the electrodes the charges start moving in the device under the influence of the electric field.


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Electrons leave the cathode and holes move from the anode in opposite direction. The recombination of this charges leads to the creation of a photon with a frequency given by the energy gap. Therefore, the electrical power applied to the electrodes is transformed into light.

Advantages: 1. OLED TV does not suffer from motion lag or motion blur as does LCD displays. In fact, OLED technology has the fastest response rate time of any type of display due to utilizing TFT active matrix (AMOLED) technology with the organic light emitting diodes. 2. OLED TV screens have near perfect viewing angle. OLEDs create light (are emissive) rather than block light. Every pixel is lit independently and that light will be seen from off axis viewing angles easily and accurately, also like plasma TV technology. 3. OLED TVs have one solid layer of plexiglass-like material which is extremely thin and light and contains all of the color compounds and TFT material needed. Therefore, the OLED panel is flexible (as in non-breakable) as well. 4. OLED televisions utilize slight electric currents to excite a combination of organic phosphorescence encased in a plastic substrate. OLED needs very little power to operate so in theory should last for a very long time as the parts are not taxed significantly. One weakness here is the blue organic LED compound which may die before the red and green compounds. 5. OLED TV will be the most energy efficient TV technology ever produced. It takes hardly any power to energize the organic light emitting molecules located in the emissive layer of the substrate. 6. OLED televisions may one day be flexible, cardboard thin and large enough to cover an 9' X 9' wall. 7. OLEDs response rate is even faster than plasma and there is no motion lag or trailer effect either. 8. OLED TVs and monitors will have the advantage of no screen burn in. 9. Due to superior technological efficiencies in manipulating lighter, simpler carbon based material, generating deeper blacks, brighter whites and all the gray scales in between should be a great strength of OLED.

Disadvantages

1. Outdoor performance


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As an emissive display technology, OLEDs rely completely upon converting electricity to light, unlike most LCDs which are to some extent reflective e-ink leads the way in efficiency with ~ 33% ambient light reflectivity, enabling the display to be used without any internal light source. OLEDs typically produce only around 200 nits of light leading to poor readability in bright ambient light, such as outdoors. Displays with some degree of reflectiveness increase their brightness as ambient light increases, so overcoming unwanted surface reflections without using any additional power.

2. Water damage.

Water can damage the organic materials of the displays. Therefore, improved sealing processes are important for practical manufacturing. Water damage may especially limit the longevity of more flexible displays.

3. Power consumption.

While an OLED will consume around 40% of the power of an LCD displaying an image which is primarily black, for the majority of images, it will consume 60–80% of the power of an LCD - however it can use over three times as much power to display an image with a white background such as a document or website. This can lead to disappointing real-world battery life in mobile devices.

4. Color balance issues.

Additionally, as the OLED material used to produce blue light degrades significantly more rapidly than the materials that produce other colors, blue light output will decrease relative to the other colors of light. This differential color output change will change the color balance of the display and is much more noticeable than a decrease in overall luminance. This can be partially avoided by adjusting colour balance but this may require advanced control circuits and interaction with the user, which is unacceptable for some uses. In order to delay the problem, manufacturers bias the colour balance towards blue so that the display initially has an artificially blue tint, leading to complaints of artificial-looking, over-saturated colors.

5. Screen burn-in.

Unlike displays with a common light source, the brightness of each OLED pixel fades depending on the content displayed.

The varied lifespan of the organic dyes can cause a discrepancy between red, green, and blue intensity. This leads to image-persistence, also known as burn-in.

http://www.ledke.com/products/LED-streetlight.html


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6. Lifespan.

The biggest technical problem for OLEDs is the limited lifetime of the organic materials. In particular, blue OLEDs historically have had a lifetime of around 14,000 hours to half original brightness (five years at 8 hours a day) when used for flat-panel displays. This is lower than the typical lifetime of LCD, LED or PDP technology—each currently rated for about 60,000 hours to half brightness, depending on manufacturer and model. However, some manufacturers displays aim to increase the lifespan of OLED displays, pushing their expected life past that of LCD displays by improving light out coupling, thus achieving the same brightness at a lower drive current. In 2007, experimental OLEDs were created which can sustain 400 cd/m2 of luminance for over 198,000 hours for green OLEDs and 62,000 hours for blue OLEDs.

Headphone:-

Headphones (or head-phones in the early days of telephony and radio) are a pair of small listening devices that are designed to be worn on or around the head over a user's ears. They are electro acoustic transducers, which convert an electrical signal to a corresponding sound in the user's ear. Headphones are designed to allow a single user to listen to an audio source privately, in contrast to a loudspeaker, which emits sound into the open air, for anyone nearby to hear. Headphones are also known as ear speakers, earphones or, colloquially, cans.

The other type, known as ear buds or earphones consists of individual units that plug into the user's ear canal. In the context of telecommunication, a headset is a combination of headphone and microphone. Headphones either connect directly to a signal source such as an audio amplifier, radio, CD player, portable media player, mobile phone, video game consoles, electronic musical instrument, or use wireless technology such as bluetooth or FM radio. Early headphones were first used by radio pioneers (crystal sets) and also by radio telephone and telegraph operators allowing a better audio reception without disturbing others around.

Initially the audio quality was mediocre and a step forward was the invention of high fidelity headphones.

https://en.wikipedia.org/wiki/Electroacoustics_%28acoustical_engineering%29

https://en.wikipedia.org/wiki/Transducer

https://en.wikipedia.org/wiki/Electrical_signal

https://en.wikipedia.org/wiki/Sound

https://en.wikipedia.org/wiki/Loudspeaker

https://en.wikipedia.org/wiki/Colloquially

https://en.wikipedia.org/wiki/Telecommunication

https://en.wikipedia.org/wiki/Headset_%28audio%29

https://en.wikipedia.org/wiki/Microphone

https://en.wikipedia.org/wiki/Amplifier

https://en.wikipedia.org/wiki/Radio

https://en.wikipedia.org/wiki/CD_player

https://en.wikipedia.org/wiki/Portable_media_player

https://en.wikipedia.org/wiki/Mobile_phone

https://en.wikipedia.org/wiki/Video_game_console

https://en.wikipedia.org/wiki/Electronic_musical_instrument

https://en.wikipedia.org/wiki/Wireless

https://en.wikipedia.org/wiki/Bluetooth

https://en.wikipedia.org/wiki/FM_radio


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The alternate in-ear versions are known as ear buds or earphones. In the context of telecommunication, a headset is a combination of headphone and microphone. Headphones either have wires for connection to a signal source such as an audio amplifier, radio, CD player, portable media player, mobile phone, video game consoles, electronic musical instrument, or have a wireless device, which is used to pick up signal without using a cable.

Advantages

No messing with wires, that get tangled or caught. You can play or pause the music from the headphones, without messing with your phone. Same with the volume. The same headphones can be used on your computer, once you've plugged them into a USB port

Disadvantages

They're much more expensive. You can buy a decent pair of wired ear buds for $20. Bluetooth headphones start at $30, and easily can cost $150. You have to charge them. Batteries last 4-8 hours. per charge. They don't last as long as high end wired headphones, due to the batteries, connectors, etc.

SGD (Speech Generating Device)

Speech-generating devices (SGDs), also known as voice output communication aids, are electronic augmentative and alternative communication (AAC) systems used to supplement or replace speech or writing for individuals with severe speech impairments, enabling them to verbally communicate their needs.

Some SGD Devices::

Static Display Speech Generating Devices

Static display speech generating devices use page overlays which need to be manually inserted into the device. These overlays can consist of symbols, photos and/or words depending on the clients abilities/needs. When one of these is selected, the device will say what has been recorded onto the device.

https://en.wikipedia.org/wiki/Telecommunication

https://en.wikipedia.org/wiki/Headset_%28audio%29

https://en.wikipedia.org/wiki/Microphone

https://en.wikipedia.org/wiki/Amplifier

https://en.wikipedia.org/wiki/Radio

https://en.wikipedia.org/wiki/CD_player

https://en.wikipedia.org/wiki/Portable_media_player


https://en.wikipedia.org/wiki/Video_game_console

https://en.wikipedia.org/wiki/Electronic_musical_instrument

https://en.wikipedia.org/wiki/Wireless


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For example, when the picture of the ‘pizza’ is selected it may produce the spoken message “I feel like ordering some pizza tonight” or a picture of a person waving may say “Hi, how are you today?” Static display speech generating devices may be suitable for individuals who have limited literacy or who find navigating through pages on a dynamic display difficult.

Dynamic Display Speech Generating Devices

Another type of speech generating device has a dynamic display similar to a touch screen computer. This technology allows the user to have multiple linking pages if desired. It then requires that the user navigate through the screens to communicate different messages. For example, the user might select the “feelings” topic on the main page which then links to a page which includes more options on “feelings”. They may then choose to select the message “I’m feeling sick”, Dynamic display speech generating devices can use photo, symbol and/or word displays and some have spelling input via an onscreen keyboard.

Spelling Based Speech Generating Devices

Spelling based speech generating devices use spelling as the method of input via a keyboard or onscreen keyboard. They use the concept of “text-to-speech” whereby the user types in the sentence/s they wish to communicate and the device then speaks out the message for their communication partner to hear. These devices are useful for someone with good literacy skills. Some devices have rate enhancement features such as: word prediction, abbreviation expansion and phrase storage.

Advantages

Speech is a very natural way to interact, and it is not necessary to sit at a keyboard or work with a remote control. No training required for users.


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Disadvantages

Even the best speech recognition systems sometimes make errors. If there is noise or some other sound in the room (e.g. the television or a kettle boiling), the number of errors will increase. Speech Recognition works best if the microphone is close to the user (e.g. in a phone, or if the user is wearing a microphone). More distant microphones (e.g. on a table or wall) will tend to increase the number of errors.

COM (Computer Output Microfilm)

Creating microfilm or microfiche from the computer. For approximately three decades before the turn of the century, COM machines were used to take print-image output from the computer either online or via tape or disk and create a film image of each page. Computerized system that converts online or stored data directly into microfilm, as images for archiving.

Computer Output Microfilm is a system that converts stored data directly to microfilm or microfiche. Computer Output Microfilm systems are still used today, mostly by organizations who need to store payroll, accounting, insurance, inventory, or employee data. Because most of these organizations have outputted the Computer Output Microfilm to microfiche, they have to manually search for a record and use a reader printer to save out a particular file. A more feasible option is to convert Computer Output Microfilm to digital image via Generation Imaging’s microfiche scanning services. Generation Imaging specializes in microfiche to PDF, TIFF, or JPEG conversions. Using high quality/high production microfiche scanners, we convert the COM microfiche to digital.

Google Glass:-

Google Glass is an optical head-mounted display, that is designed in the shape of a pair of eyeglasses. It was developed with the mission of producing a ubiquitous computer. Google Glass displayed information in a smartphone-like hands-free format.

http://www.businessdictionary.com/definition/system.html

http://www.businessdictionary.com/definition/online.html

http://www.businessdictionary.com/definition/data.html

http://www.businessdictionary.com/definition/microfilm.html

http://www.businessdictionary.com/definition/image.html

https://en.wikipedia.org/wiki/Optical_head-mounted_display

https://en.wikipedia.org/wiki/Ubiquitous_computing

https://en.wikipedia.org/wiki/Smartphone


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Google Glass was developed by Google X, the facility within Google devoted to technological advancements such as driverless cars. Google Glass is smaller and slimmer than previous head-mounted display designs.

Features Touchpad: A touchpad is located on the side of Google Glass, allowing users to control the device by swiping through a timeline-like interface displayed on the screen.

Sliding backward shows current events, such as weather, and sliding forward shows past events, such as phone calls, photos, circle updates, etc.

Camera: Google Glass has the ability to take photos and record 720p HD video.

Display: The Explorer version of Google Glass uses a liquid crystal on silicon (LCoS)(based on an LCoS chip from Himax), field-sequential color system, LED illuminated display.

The display's LED illumination is first P-polarized and then shines through the in-coupling polarizing beam splitter (PBS) to the LCoS panel. The panel reflects the light and alters it to S-polarization at active pixel sensor sites. The in-coupling PBS then reflects the S-polarized areas of light at 45° through the out-coupling beam splitter to a collimating reflector at the other end. Finally, the out-coupling beam splitter (which is a partially reflecting mirror, not a polarizing beam splitter) reflects the collimated light another 45° and into the wearer's eye.

Advantages of Google Glasses:

Hands-free device to check email and personal info without having to hold phone Device remembers interactions to give relevant search/navigation results Advertisement High-speed data connection (3G or 4G)

Disadvantages of Google Glasses:

Expensive Privacy Bulky design

https://en.wikipedia.org/wiki/Autonomous_car

https://en.wikipedia.org/wiki/Google%2B

https://en.wikipedia.org/wiki/Liquid_crystal_on_silicon

https://en.wikipedia.org/wiki/Himax

https://en.wikipedia.org/wiki/Field-sequential_color_system

https://en.wikipedia.org/wiki/Light-emitting_diode

https://en.wikipedia.org/wiki/Polarizing_beam_splitter

https://en.wikipedia.org/wiki/Active_pixel_sensor

https://en.wikipedia.org/wiki/Collimator

Sub.: Computer Fundamental Chapter – 3 B.C.A. Sem

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1. Introduction Computer systems need to store data on a permanent basis for several days, several months, or even several years. So, an additional memory called auxiliary memory or secondary storage is used with most computer systems. This section of memory is used to store large volume of data on a permanent basis, which can be partially transferred to the primary storage as and when required for processing. Data is stored in secondary storage in the same binary codes as in main storage and is made available to main storage as needed. A wide range of devices and media have been developed for use as secondary storage in computer systems. The popular item used in today’s computer systems are floppy disk, hard disk, CD, DVD, Zip Drive, Pen Drive etc.

3 Data Storage

Topic Covered 1. Introduction 2. Types of Magnetic Storage Devices

o Floppy Disk o Hard Disk o Magnetic Tape o Magnetic Disks

3. Storage Mechanism of Magnetic Storage Devices o Tracks o Sectors o Clusters o Cylinders

4. Reading / Writing Data to and from Storage Devices o Seek Time o Rotation Delay – Latency o Access Time o Response Time

5. Other Storage Devices o USB - Pen Drive, CD, DVD, Blue-Ray Disk etc. o Flash Memory, Cloud Storage (Like Google Drive, OneDrive etc.)


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1. Types of Magnetic Storage Devices A Magnetic storage device is mainly two types

Magnetic Tape Magnetic tape is one of the popular storage medium for large data that are sequentially accessed and processed. The magnetic tape is a 12.5 mm to 25mm wide plastic film-type and 500 meter to 1200 meter long which is coated with magnetic material. The cost of storing data in tapes is inexpensive (low - cost). Information is recorded the tap in the form of tiny invisible magnetized and non-magnetized spots. A character is recorded per frame using one of computer codes such as BCD and EBCDIC codes. Magnetic tape speed is inches per second, high performance taps have speed more than 200 inches per second. Advantages:- 1. Compact:- A 10-inch diameter reel of tape is 2400 feet long and is able to hold 800,1600 or 6250 characters. • The maximum capacity of tape is 180 million characters. 2. Low Cost:- The cost of storing characters is very less as compared to other storage devices. 3. Fast:- Copying data is easier and fast. 4. Long term Storage and Re- usability:- Magnetic tape can be used for long term storage and a tape can be used repeatedly without loss of data. Disadvantages:- 1. No direct Access:- It is a sequential access device and hence data recorded on tape cannot be accessed directly. 2. Indirect Interpretation:- The contents of a tape cannot be interpreted and verified directly. 3. Environmental Problems:- Dust and uncontrolled humidity or temperature levels can cause tape reading errors.


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Magnetic Disk They are available in three forms:: 1) Floppy Disk 2) Hard Disk 3) Zip Disk Floppy Disk:- A floppy disk is a round, flat piece of flexible plastic coated with magnetic oxide. It is encased in square plastic jacket cover. The jacket gives handling protection to the disk surface. It has a special liner that provides a wiping action to remove dust particular that are harmful for the disk surface and the read/write head. It is known as Floppy disks because they are made of flexible plastic which can band. They are very cheap as compared to other storage devices. They were introduced by IBM in 1972 and are now being produced in various sizes and capacities by many manufacturers. A floppy disk drive is a device that is used to read/write data from/to floppy disks. A floppy disk can be very easily loaded into or unloaded from a floppy-disk drive just by slipping the disk invisible the drive’s slot or by pressing the eject button on the drive. Types of Floppy Disk:- Floppy disk and its corresponding drives are available in two sizes i.e. 51/4 – inch and the 31/2– inch. The 31/2 – inch diskettes are widely used today. 1. The 51/4 – inch diskette:- It is a floppy disk of 51/4 – inch diameter. The disk is encased in square jacket that is harder than the disk itself but still flexible. The disk is rotates inside its jacket cover whose inner side is smooth and permits free rotation of the disk. That can be stored per square inch area on one surface of the disk. 2. The 31/2 – inch diskette:- It is a floppy disk of 31/2– inch diameter. The disk is encased in a square hard plastic jacket cover. The jacket cover has a cutout for the read/write head to make contact with the disk surface. This diskettes is covered with a sliding metal piece. When the diskette is inserted into the drive, this covers slides back to expose the disk surface to the read/write head.


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Hard Disk:- Hard disks are the most popular secondary storage device. It is a thin magnetic disk made of metal plate, which coated on both sides with magnetic materials. The hard disk platters come in many sizes ranging from 1 to 14- inch diameter. Information is stored in these tracks on both the sides. Increase the storage capacity, the disk pack consists of multiple hard disk platters mounted on a single central shaft. The disk drive of a disk pack has a separate read/write head for each disk surface excluding the upper surface of the topmost disk and the lower surface of the lowermost disk. These two surfaces are not used for data recording in a disk pack. Disk packs are stored in a plastic case. Different disk packs can be mounted on the same disk pack drive at different instance of time. The disk drives consist of motor to rotate the disk pack about its speed. Its speed is 5400 revolution per minute.


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Zip Disk:- Zip disks are high capacity, removable, magnetic disks, which can be read written by ZIP drives from IOMEGA Corporation. Zip disks are similar to floppy disks, expect that they are much faster, and have a much greater capacity. Floppy disk typically hold 1.44 megabytes, ZIP disks are available in two sizes, namely 100 megabytes and 250 megabytes. IOMEGA also sells a higher capacity, higher performance drive called the JAZ / JAZZ drive. JAZ drives comes in 1 gigabyte and 2 gigabyte sizes. Zip drives are available as internal or external units. Advantages:- Easy to use Storage capacity is bigger than floppy disk Faster than floppy disk Easy to carry around Disadvantages:- Expensive Data transfer between drive and your computer is very slow.

2. Storage Mechanism of Magnetic Storage Devices Tracks:- The data stored on a disk is generally organized into sectors and tracks. Unlike the continuous spiral of data on a CD or a disc record, the tracks on a magnetic disk are concentric circles. At least one head is required to read a single track. Sectors are wedge-shaped regions of the disk, similar to slices of pizza. With respect to disk geometries the terms track and cylinder are closely related. For a single or double sided floppy disk track is the common term and for more than two heads cylinder is the common term. Sectors:- A sector is the smallest storage unit that is addressable by a hard drive, and all information stored by the hard drive is recorded in sectors. Tracks and sectors form a polar coordinate system that the computer uses to keep track of which data has been written to which regions of a disk. Clusters:- Clusters are allocation units for data on various file systems (FAT, NTFS, etc.), where data mainly consists of files. Clusters are not directly affected by the physical or virtual geometry of the disk


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Cylinders:- A cylinder comprises the same track number on each platter, spanning all such tracks across each platter surface that is able to store data (without regard to whether or not the track is "bad"). It is a three-dimensional structure. Any track comprising part of a specific cylinder can be written to and read from while the actuator assembly remains stationary. And one way in which hard drive manufacturers have increased drive access speed has been by increasing the number of platters which can be read at the same time.

3. Reading / Writing Data to and from Storage Devices Seek Time:- Seek time is one of the three delays associated with reading or writing data on a computer's disk drive, and somewhat similar for CD or DVD drives. The others are rotational delay and transfer time, and their sum is access time. In order to read or write data in a particular place on the disk, the read/write head of the disk needs to be physically moved to the correct place. This process is known as seeking, and the time it takes for the head to move to the right place is the seek time. Seek time for a given disk varies depending on how far the head's destination is from its origin at the time of each read or write instruction; usually one discusses a disk's average seek time. Rotational Delay – Latency:- Rotational delay is one of the three delays associated with reading or writing data on a computer's disk drive, and somewhat similar for CD or DVD drives. The others are seek time and transfer time, and their sum is access time. The term applies to rotating storage devices (such as a hard disk or floppy disk drive, and to the older drum memory systems). The rotational delay is the time required for the addressed area of the disk (or drum) to rotate into a position where it is accessible by the read/write head.


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Access Time or Response Time:- The access time or response time of a rotating drive is a measure of the time it takes before the drive can actually transfer data. The factors that control this time on a rotating drive are mostly related to the mechanical nature of the rotating disks and moving heads. It is composed of a few independently measurable elements that are added together to get a single value when evaluating the performance of a storage device.

4. Other Storage Devices Other storage devices are called Optical Disks They are available in these forms:: 1. CD-Compact Disk 2. DVD – Digital Versatile Disk 3. Blue Ray 4. HVD – Holographic Versatile Disk 5. Pen Drive. CD (Compact Disk):- • The CD is a shiny, silver color metal disk of 51/4 – inch diameter. • It has a storage capacity of about 650 megabyte. It is a read-only storage medium. • These disks come pre-recorded and the information stored on them cannot be altered. Work of CD:: Information in CDROM is written by creating on the disk surface by shining a laser beam. As the disk rotates the laser beam traces out a continuous spiral (twist). The sharply focused beam creates a circular pit of around 0.8 micrometer diameter, whenever a ‘1’ (one) is to be written and no pit (also called a land) if a ‘0’ (zero) is to be written. The CDROM with pre-recorded information is read by a CDROM reader which uses a laser beam for reading. As the disk rotates the head senses pits and land. This is converted to 1s and 0s by the electronic interface and sent to the computer. Advantages:- To cost per bit of storage CD is very low because of their low cost and enormous storage density. Optical disk drives do not have any mechanical read/write heads to rub against or crash into the disk surface.


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Optical disk drives have a data storage life in excess of 30 years. Due to their compact size and light weight, they are easy to handle, store and portable. Limitations:- It is a read-only storage medium. Data once recorded, cannot be erased and hence this disk cannot be reused. Their data access speed is slower than magnetic disks. They require a more complicated drive mechanism than magnetic disks. DVD (Digital Versatile Disk):- Digital Versatile Disk is an optical disk storage media format that can be used for data storage, including movies with high video and sound quality. DVDROM uses the same principle as a CDROM for reading and writing. Work of DVD:: In DVDROM a smaller wavelength laser beam (650 nm) is used. A lens system to focus the laser beam is used which can focus on two different layers on the disk. One each layer data is recorded. Thus the capacity can be doubled. The recording beam is sharper compared to CDROM and the distance between successive tracks on the surface is smaller. The total capacity of DVDROM is 8.5 GB. In both CDROMs and DVD ROMs, the density of data stored (pits and lands per unit length) is constant throughout the spiral track. Advantages:- Compared to CD large storage capacity. Limitations:- More expensive Like CDs, DVDs also can be damaged if not handle properly. Blue – ray Disk:- Blue – ray Disk is an optical disc storage media format. Its use are high-definition video and data storage. The disk has the same dimensions as a standard DVD or CD. The name Blue-ray Disk is derived from the Blue laser (violet colored) used to read and write this type of disk. A dual layer Blue-ray Disk can store 50 GB, almost six times the capacity of a dual layer DVD. Blue-ray Disc was developed by Blue-ray Disc association, a group of companies representing consumer electronics, computer hardware, and motion picture production.


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USB - Pen Drive:- A flash drive/ pen drive consist of a small printed circuit board cased in a robust plastic or metal casing. This drive is very easy to carry in your pocket like pen that’s why it is known as Pen drive. Most flash drives use a standard type-A USB connection allowing them to be connected directly to a port on a personal computer. Essential components:- Male type – A USB connector:- Provides an interface to the host computer. USB storage controller:- Implements the USB host controller and provides a linear interface to block-oriented aerial flash devices. NAND flash memory chip:- Stores data. NAND flash is typically also used in digital cameras. Crystal oscillator:- Produce the device’s main 12 MHz clock signal and controls the device’s data. Advantages:- Flash drives are damage to scratches and dust that were problematic for previous forms of portable storage, such as compact disks and floppy disks. It is portable. Flash drives implement the USB mass storage device class, meaning that most modern operating systems can read and write to flash drives without any additional device drives. Flash drives are also a relatively form of storage. Nowadays 1 GB and 2 GB drives are available. Disadvantages:- Compared optical disk it is costly. Most USB flash drives do not employ a write-protect mechanism. Flash drives have most strong features of storing a data but can still be damaged or have data corrupted if an impact loose circuit connections. Components of Pen drive:-

One end of device is fitted with a single male type-A USB connector.


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Inside the plastic casing is a small printed circuit board. Mounted on this board is some simple power circuitry and a small number of surface - mounted integrated circuits (ICs). One of these ICs provides an interface to the USB port, another drives the onboard memory, and the other is the flash memory. FLASH MEMORY (Storage device) Today all of you are aware with a word called USB/Pen Drive. In fact USB/Pen drive is a special type of EEROM which is known as FLASH Memory. Flash memory is a type of constantly nonvolatile memory that can be erased and reprogrammed in units of memory called blocks. It is variation of electrical erasable programmable read-only memory (EEPROM) which, unlike flash memory, is erased and rewritten at the byte level, which is slower than flash memory updating. Flash memory gets its name because the microchip is organized so that a section of memory cells are erased in a single action or “flash”. We store and transfer all kind of files on our computer—digital photographs, music files, word processing documents, PDF etc. But sometimes your computer’s hard drive isn’t exactly where you want your information. If you want to make backup copies of files that live off your system or if you worry about your security, portable storage devices that use a type of electronic memory called flash memory may be the right solution. Flash memory is used for easy and fast information storage in computer, digital cellular phones, digital cameras, and digital setup boxes. It is used more like a hard drive than as RAM. In fact flash memory is known as a SOLID STATE storage device.


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Cloud storage: Cloud storage is an industry term for managed data storage through hosted network (typically Internet-based) service. Several types of cloud storage systems have been developed supporting both personal and business uses With the increasing information that we humans access , the storage requirements to accumulate that information keeps on increasing , May it be a collection of doc files or some movies or some softwares or some songs, the data requirements keeps on increasing day by day.

What here is more important is that how we access the big data whether it is for the personal use or professional use. People either prefer upgrading their hard drives or even sometimes prefer using compact disks as well, but with the advancement in technology everyone wants access to data on the go, without having the need to carry physical hardware and hence Cloud Storage requirements fall into place. Cloud storage means storing data online so that we can access it from any place without actually carrying the data servers with us. Cloud storage can be classified into four types:: Personal / Mobile Cloud Storage :- This is a type of cloud of type of cloud storage that we use in our daily lifes, We use android and I-phone these days, for our safety we have already synced our phones online so that even if our phone is lost , we can backup it on the new device anytime as per our convenience. Let’s consider the use case study of i-cloud , the I phone cloud storage platform, that’s what is a personal cloud storage.

Publicly Available Cloud Storage :- In this type, the user uses a public-ally available cloud which he has either rented or subscribed for a certain period of time. Anyone with access to that cloud with the User’s log in credentials could access that data from any part of the world. Privately Available cloud storage :- The company providing cloud storage services sets up the data center in the user’s allocated space. The main reason behind having a privately available cloud storage is the requirement of a secure platform and restricted access to the data. A hybrid available cloud storage :-In this case the data is available public-ally but some parts of the data is private and hence is restricted to some users only. So this is an On and off model where it can be switched from public to private or private to public anytime as per user’s convenience.

Advantages and Benefits of Cloud Storage :

The cloud computing is a rapidly involving concept in the 21st century and it brings a excess of advantages, the biggest one being the data accessibility from any part of the world. Not only does it increases work efficiency but also reduces costs of operations in the longer run.


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The second biggest advantage of having a cloud storage is the benefit of having remote data backups as per our own convenience and hence it reduces the costs to setup the disaster recovery and backup units.

Disadvantages Of cloud Storage :

The disadvantages to cloud storage are very few, but the biggest one being the increased usage of bandwidth to access the data that increases the costs of operations a bit. Secondly, if your internet connection is not having a great speed , you might not be able to access the data.

If you're ready to take the plunge into storing your files, photos and more in the cloud but need help deciding which service is right for your needs and wallet, we've got you covered with our in-depth cloud storage comparison.

Cloud storage comparison

OneDrive Dropbox Google Drive Box

Amazon Cloud Drive

File size restrictions? 10GB

10GB with website, none with Dropbox apps

5TB

250MB for free plan, 5GB for paid personal plan

2GB*

Free storage? 5GB** 2GB 15GB 10GB No***

Can I earn extra free storage?

No** Yes No No No

Paid plans $2/month for 50GB**

$10/month for 1TB

$2/month 100GB, $10/month for 1TB

$10/month for 100GB

$12/year for unlimited photos, $60/year for unlimited files

OSes supported

Windows, Mac, Android, iOS, Windows Phone

Windows, Mac, Linux, Android, iOS, Windows Phone, BlackBerry, Kindle Fire

Windows, Mac, Android, iOS

Windows, Mac, Android, iOS, Windows Phone, BlackBerry

Windows, Mac, Android, iOS, Kindle Fire


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• There is no file size limit with desktop apps. • In early 2016, Microsoft will change its free storage from 15GB to 5GB and offer a $2 per month for 50GB paid plan instead of its earlier offerings. It will also no longer let you earn free storage. • Amazon Cloud Drive offers limited free storage with an Amazon Prime subscription. • Wireless Devices key board, mouse

Sub.: Computer Fundamental Chapter – 4 B.C.A. Sem - 1

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1. Introduction to binary codes

BIT Bit is short for binary digit and single unit of information that can have a value of either ON or OFF. For example, 2 to the power of 8 give 256. I.e we have 28= 256 color combination (8bit). Bit is a smallest unit of memory storage Nibble 4 bit or half byte is nibble Bytes Group of 8 bit is known as 1 byte The largest units are KB (Kilo Byte) , MB (Mega Byte) , GB (Giga Byte) , TB (Terra Byte), HB (Hexa Byte) etc o 1KB = 103 bytes (1024 bytes) o 1 MB = 106 (1024 KB) o 1 GB = 109 (1024 MB) o 1 TB = 1012 (1024 GB) o 1 HB = 1015 (1024 TB)

4.1 Numbering system and Codes Topic Covered

1. Introduction to binary codes Nibble / Bit / Byte / Carry Bit / Parity Bit / Sign Bit KB / MB / GB / TB / HB / etc…

2. Types of Number System Binary / Octal / Decimal / Hexa - Decimal

3. Conversion Binary to Octal , Decimal and Hexa-Decimal Decimal to Binary , Octal and Hexa-Decimal Octal to Binary , Decimal and Hexa-Decimal Hexa-Decimal to Binary , Octal and Decimal

4. Binary Arithmetic Addition Subtraction [ 1st Compliment and 2nd Compliment] Multiplication division

5. Types of Codes ASCII , BCD , EBCDIC , UniCode

6. Parity Check Even Parity System / Odd Parity System


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Carry Bit An arithmetic operation that occurs in the course of addition when the sum of the digits in a given position equals or exceeds the base of the number system; a multiple base is subtracted from this sum so that the remainder is less than the base, and the numbered then added to the next-higher-order digit. Parity Bit Single Bit Added to a binary data transmission used to indicate if whether the 0 /1 within that data transmission is an even or odd number

1 0 1

Sign Bit In computer science the sign bit is a computer numbering format which indicates the sign of the number. If the sign bit is 1 the number is negative (in the case of 2’s complement integers) or non-positive (for the case of 1’s complement). If the sign bit is 0 the number is positive.

1 0 0 1

2. Types of Numbering system Binary The prefix “bi-” stands for 2 The binary number system is a Base 2 number system. There are 2 symbols that represent quantities 0, 1 Each place value in a binary number is a power of 2. 1100,1001,0101, etc are the example of Binary Octal The Octal stands for 8 The Octal number system is a Base 8 number system. There are 8 symbols that represent quantities 0 to 7 Each place value in octal number is a power of 8. 7,3,6 etc are the example of Octal Decimal The Decimal stands for 10 The Decimal number system is a Base 10 number system.

1 1

Parity Bit 7 in hex

Sign Bit 1 in Octal

MSB


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There are 10 symbols that represent quantities 0 to 9 3,6,9 etc are the example of Decimal Hexadecimal The Hexadecimal stands for 16 The Hexadecimal number system is a Base 16 number system. There are 16 symbols that represent quantities 0 to 9 and A to F. Each place value in a Hexadecimal number is a power of 16. 12,3,9,AC, F1 etc are the example of Hexadecimal

3. Conversion In conversion from decimal to any other number system, the steps to be followed are : 1. Divide the decimal number by the base of the required number system. 2. Note the remainder in one column and divide the quotient again with the base. Repeat this process until the quotient is reduced to a zero. Binary to Octal , Decimal and Hexa-Decimal Converting Binary to Decimal o E.g. 101011 - Binary o Here power of 2 start with 0 and will be increase and multiply with digit 101011-binary

Bit7

Bit 6

Bit 5 Bit 4

Bit 3

Bit 2

Bit 1 Bit 0

27 26 25 24 23 22 21 20

128 64 32 16 8 4 2 1

1 0 1 0 1 1

1*(25) + 0*(2^4) + 1*(2^3) + 0*(2^2) + 1*(2^1) + 1*(2^0) = 1*32 + 0*16 + 1*8 + 0*4 + 1*2 + 1*1 = 32 + 0 + 8 + 0 + 2 + 1 = 43 (in decimal) Converting Binary to Octal o You can convert binary to decimal and then decimal to octal. Another method is group of 3 bit from backside and find equivalent octal no by seeing table. To convert a number from binary to octal and vice-versa, the following table must be kept in mind :

Multiply with these values


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Binary Octal

000 0 001 1 010 2 011 3 100 4 101 5 110 6 111 7

The binary number must be divided into groups of three from the octal point – to the right in case of the fractional portion and to the left in case of the integer portion. Each group can then be replaced with their octal equivalent. o E.g. 101011001 - Binary 101 011 001 5 3 1 o So 531 octal number is equivalent to binary 101011001 Converting Binary to Hexadecimal o You can convert binary to decimal and then decimal to hexadecimal. Another method is group of 4 bit and find equivalent octal no by seeing table. o E.g. 101011001 - Binary 0001 0101 1001 1 5 9 o So 159 hexadecimal number is equivalent to binary 101011001 Decimal to Binary , Octal and Hexa-Decimal Converting Decimal To Binary o E.g. 25 Decimal

o Now take reverse 11001 = Binary equivalent of 25

Converting Decimal To Octal o E.g. 90 Decimal

2 5

2 1 2

1

2 6 0 2 3 0 2 1 1 2 0 1


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o Now take reverse 132 = Octal equivalent of 90 Converting Decimal To HexaDecimal o E.g. 335 Decimal

o Now take reverse 14F = HexaDecimal equivalent of 335 Octal to Binary , Decimal and Hexa-Decimal Converting Octal To Decimal o Here power of 8 start with 0 and will be increase and multiply with digit o Use this table and multiply the digits with the position values

Digit 8

Digit 7

Digit 6 Digit 5

Digit 4

Digit 3

Digit 2

Digit 1

87 86 85 84 83 82 81 80

…… …… 32768 4096 512 64 8 1

o E.g. 157-octal 1*(8^2) + 5*(8^1) + 7*(8^0) = 64 + 40 + 7 = 111 (Decimal Number) Converting Octal To Binary o We can convert octal to decimal and then decimal to binary. o Another method is that directly write equivalent 3 bit binary number from table. Each octal digit is replaced with the appropriate ‘triple’ of binary digits. o E.g. 157-octal 1 5 7 001 101 111 o So.1101111 is binary equivalent of octal number 157.

90 8 11 2 8 1 3 8 0 1

335 16 20 15=F 16 1 4 16 0 1


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Converting Octal To Hexa-Decimal o In this conversion we have to convert octal to decimal number and then convert decimal to Hexadecimal number Hexa-Decimal to Binary , Octal and Decimal Converting Hexa-Decimal To Decimal o Here power of 16 start with 0 and will be increase and multiply with digit. o We need to keep a simple table in mind before we attempt any conversion from hexadecimal or vice-versa.

Hexadecimal Decimal Binary

0 0 0 1 1 1 2 2 10 3 3 11 4 4 100 5 5 101 6 6 110 7 7 111 8 8 1000 9 9 1001 A 10 1010 B 11 1011 C 12 1100 D 13 1101 E 14 1110 F 15 1111

o Use this table and multiply the digits with the position values

Digit 8

Digit 7

Digit 6

Digit 5

Digit 4

Digit 3

Digit 2

Digit 1

167 166 165 164 163 162 161 160

…… …… ….. …… 4096 256 16 1

o E.g. A7D - Hexadecimal number A*(16^2) + 7*(16^1) + D*(16^0) = 10*(16^2) + 7*(16^1) + 13*(16^0) = 10*256 + 7*16 + 13*1 = 2560 + 112 + 13 = 2685 (Decimal number)


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Converting Hexa-Decimal To Binary o We can convert hexadecimal to decimal and then decimal to binary. Another method is that directly write equivalent 4 bit binary number from table. E.g. 3A7D-hexadecimal number 3 A 7 D 0011 1010 0111 1101 So. 11101001111101 is binary equivalent of octal number 3A7D Converting Hexa-Decimal To Octal o In this conversion we have to convert hexadecimal to decimal number and then convert decimal to octal number.

4. Binary Arithmetic Addition o For binary Addition the following rules are to be considered : 0 + 0 = 0 0 + 1 = 1 1 + 0 = 1 1 + 1 = 0 (carry 1 to the next column to the left) 1 + 1 + 1 = 1 (carry 1 to the next column) o e.g. 1 Add two binary numbers 11011 and 111 Carry 1 1 1 1 1 1 1 1 1 + 1 1 1 1 0 0 0 1 0 (Answer) Subtraction [ 1st Compliment and 2nd Compliment] o For Binary Subtraction the following rules are to be considered: 0 – 0 = 0 1 – 0 = 1 1 - 1 = 0 0 – 1 = 1 Borrow 1 o E.g. 1111-110 1 1 1 1 -- 1 1 0 1 0 0 1 o E.g. 101010 – 1111 1 0 1 0 1 0 -- 1 1 1 1 1 1 0 1 1 o Compliment : o How do we find the 1’s complement of a binary number? We have to invert all the bits.

Number : 1011001 1’s complement : 0100110


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Calculation of 2's Complement o To calculate the 2's complement of an integer, invert the binary equivalent of the number by changing all of the ones to zeroes and all of the zeroes to ones (also called 1's complement), and then add one.

Number : 1011000 1’s complement : 0100110

+ 1 2’s complement : 0100111

Subtraction of 2 binary numbers: o Though there are other methods of performing subtraction, we will consider the method of subtraction know as complementary subtraction. This is a more efficient method of subtraction while using electronic circuits. We will be following three steps to perform subtraction : Find the complement of the number you are subtracting. To the complement of the number we obtained in step 1, we add the number we are subtracting from. If there is a carry of 1 add the carry to the result of the addition else re complement the sum and attach a negative sign. o Consider the following example of subtraction : o E.g. 1 :- 1010101 – 1001100 Step-1. Find the complement of 1001100 0110011 Step-2. Add the number you are subtracting from Carry 1 1 1 0 1 1 1 1 0 1 0 1 0 1 + 0 1 1 0 0 1 1 0 0 0 1 0 0 0 + 1 (Continue since there is a carry of 1) 0 0 0 1 0 0 1 (Answer) o E.g. 2 101100 – 11100101 Step-1. Find the complement of 11100101 00011010 Step-2. Add the number you are subtracting from Carry 0 1 1 1 0 0 1 0 1 1 0 0 + 0 0 0 1 1 0 1 0 0 1 0 0 0 1 1 0


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Step-3. Since there is no carry we a. re complement the result 10111001 b. attach a negative sign - 10111001 (Answer) 2's Complement Subtraction o Two's complement subtraction is the binary addition of the minuend to the 2's complement of the subtrahend (adding a negative number is the same as subtracting a positive one). o For example, 7 - 12 = (-5) 0000 0111 = +7 + 1111 0100 = -12 1111 1011 = -5 o Here 7 is minuend and converted into binary 0000 0111. o -12 is subtrahend and need to find 2’s complement. o Addition with minuend. o Answer will be again converted into 2’s complement and sign will be negative (because we have to subtract large number from small number) Multiplication o For Binary Multiplication the following rules are to be considered: 0 * 0 = 0 0 * 1 = 0 1 * 0 = 0 1 * 1 = 1 o Ex. Multiply 1101 by 110. 1 1 0 1 Multiplicand * 1 1 0 Multiplier 0 0 0 0 1 1 0 1 Partial Product 1 1 0 1 1 0 0 1 1 1 0 Final Product Division o For Binary Division the following rules are to be considered: 0 / 0 = 0 0 / 1 = 0 1 / 0 = Undefined 1 / 1 = 1 o Ex. Divide 1010 by 101 1 0 Quotient Divisor1 0 1) 1 0 1 0 Dividend 1 0 1 0 0 0


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5. Types of Code ASCII Code:- American Standard Code for Information Interchange (ASCII) is a character encoding based on the English alphabet. ASCII codes represent text in computers communications devices, and other devices that work with text. ASCII developed from telegraphic codes and its first commercial used was a seven-bit tele printer code promoted by Bell data services. Work on ASCII began in 1960. The first edition of the standard was published in 1963, a major revision in 1967, and the most recent update in 1986.

ASCII codes define for 128 characters there are 33 non-printing control characters that affect how text is processed 94 are printable characters. The ASCII was developed by a committee of the American Standards Association, called the X3 committee. The ASA now became as ANSI (American National Standard Institute). Like other character encoding, ASCII specifies a correspondence between digital bit patterns and character symbols. BCD Code:- In number system if we view digit values for hex, the numbers 0-F, they represent the values 0-15 in decimal. We wish to use a binary equivalent of the decimal system this system is called Binary Coded Decimal or BCD. The BCD value for the decimal number 5319. since there are four digits in our decimal number, they are :: Thousands Hundreds Tens Units 5 3 1 9 00000101 00000011 00000001 00001001 In BCD code there was a PACKED BCD cod that is require 4 bytes to store the BCD numbers.


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For example we can stored upper number 5319 in PACKED BCD code, we would only required 2 bytes, half the storage Now we can see that how it store in the memory using PACKED BCD code::

Thousands – Hundreds Tens - Units 5 3 1 9 01010011

0011001

EBCDIC Code:- EBCDIC (Extended Binary Coded Decimal Interchange Code) is an eight – bit character set was developed by International Business Machines (IBM). EBCDIC is an extended BCD code and there are 2 extra bit as compared to BCD. It was the character set used on most computers manufactured by IBM prior 1981. EBCDIC is not used on the IBM PC and all subsequent “PC clones”. There computer systems are ASCII as the primary character and symbol coding system. EBCDIC is widely considered to be an outdated coding system. It is an 8-bit code; it can be easily divided into two 4-bit groups. Each these 4-bit groups can be represented by 1 hexadecimal number digit. Unicode:- Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems. Developed in conjunction with the Universal Character Set standard and published in book form as The Unicode Standard. Unicode's success at unifying character sets has lead to its extensive and major use in the internationalization and localization of computer software. The standard has been implemented in many recent technologies, including XML, the Java programming language, the Microsoft .NET Framework, and modern operating systems.

6. Parity Check Even Parity System:- The parity checking circuit counts the number of 1 bit and adds the parity bit to make the total number of 1 bit an EVEN number. Examples 1. – 1 0 0 1 0 0 1 1 has four 1s so the parity bit would be a 0 2. – 1 1 0 0 1 1 1 0 has five 1s so the parity bit would be a 1 Odd Parity System:- The parity checking circuit counts the number of 1 bit and adds the parity bit to make the total number of 1 bit an ODD number. Examples 1. – 1 0 0 1 0 0 1 1 has four 1s so the parity bit would be a 1 2. – 1 1 0 0 1 1 1 0 has five 1s so the parity bit would be a 0


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1. Introduction Interpreter:- An Interpreter is a program which converts the higher level language in lower level language or assembly language or binary language i.e. the language of 0’s and 1’s. It reads one line of code at a time converts it into binary language and then runs the code on the machine. So the initial start up time to run the program is almost unimportant. If there is any error on the middle of the program then the program is interrupted in between. After removing the error the programs needs to run again from the beginning. Languages like BASIC is interpreter based languages. So in this interpreter converts one line of code at a time, and then runs it. Compiler:- A compiler is also a program which converts the higher level language in lower level language. In case of compiler, it reads a whole block of code at a time, converts it into executable code, and runs the code. The initial start up time to run program is more as compared to Interpreter. Once the code is compiled, then the initial start up time to run the program is negligible. Languages like C, C++ are compiler based languages.

4.2 Languages, Operating Systems and Software Packages

Topic Covered 1. Introduction 2. Translator [ Assembler , Compiler , Interpreter] 3. Types of Languages

Machine Level Language Assembly Language High Level Language [ 3GL , 4GL , 5GL , etc]

4. Types of Operating Systems Batch Operating System Multi Processing Operating System Time Sharing Operating System Online and Real Time Operating System

5. Uses and applications of Software Packages Word Processing Packages Spread Sheet Packages Graphical Packages Database Packages Presentation Packages Animation , Video , Sound Packages


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Assembler:- An Assembler is a computer program that takes computer instructions and converts them into a pattern of bits that the computer can understand and perform by it certain operations. Very fast and small executable code but very tedious to write.

2. Types of Languages A language is a system of communication. A programming language consist of all symbols, character, and usage rules that permit people to communicate with the computer. They are created for special purpose that may be suitable for many types of applications. Computer language can be classified into three broad categories:-

Language

Low level Middle level High level

Low Level Language Machine language and assembly language are known as low level languages. 1. Machine Language:- It is made up of only two symbols “0” & “1” with all its different combinations. So all the instruction are coded in 0s and 1s. There is a specific binary code for each instruction of the binary, code for certain operation differs from computer to computer. An instruction prepared in any machine language has a two part format. First part is the command or operation, and it tells the computer what function to perform. Every computer has an operation code or opcode for each of its functions. The second part of the instruction is the operand, and it tells the computer where to find or store the data or other instructions that are to be manipulated. Thus, each instruction tells the control unit of the CPU what to do and the length and locations of the data fields that are involved in the operation. Operation code is the function that must be performed and operands are the variables involved in this function.


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For e.g.

Opcode(Operation code) Operand

(Address)

0010 0000011100

Advantages:- Very fast execution of program. No need for any translator. Disadvantages:- It is Machine dependent. Hardware knowledge is required. Difficult to program. It is difficult to correct errors of the program. Time consuming code. 2. Assembly Language:- Machine language was tedious to code and errors were expected to arise in bulk. To reduce the programmer’s burden mnemonic codes and symbolic addresses were developed. A mnemonic is any kind of mental trick we use to help us remember. Mnemonics come in various shape and sizes all of them useful in their own way. That is sub or s for subtract, mvc for move character. For adding two numbers and printing out the result could be written in the following. CLA A ADD B STA C TYP C HLT This would mean take A, and B, store the result in C and halt. We have considered only five operation codes that will be used in writing program. Like this there can be more that hundred operations codes available with a particular computer. The language that substitutes letters and symbols for the numbers in the machine language program is called assembly language or symbolic program. The translator program that translates an assembly code into the computers machine code is called an assembler. The assembler is a system program, which is supplied by the computer manufacturer.


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Format of assembly language is similar to machine language. Examples of commands are ADD, SUB etc. Examples of variable name are SUM, AVERAGE etc.

Mnemonic code Symbolic Address

Assembler:- “A computer program, which translate an assembly language program to its machine language equivalent.”

Assembly Language

Machine LanguageAssembler

Middle Level Language Some languages having features of low level as well as high level language. Such types of languages are known as middle level language. C and C++ are the examples of middle level language. High Level Language Writing of programmer in machine language or assembly language requires a deep knowledge of the internal structure of the computer. Older programming languages have to remember all the operation codes of the computer and know in detail what each code does and how it affects the various registers of the computer. The computer programmers have to concert on the logic of the problem rather than concerned with internal structure. High level language is basically symbolic language that uses English words and/or mathematical symbols rather than mnemonic codes. Every instruction, which the programmer writes in a high level language, is translated into many machine language instructions. Advantage:- High-level language is machine independent. High-level language is easy to learn and use for users. No worry about how to store his numbers in the computer. The programmer need not know the machine instruction the data format and is on. If any error occurs in the program at that computer take care of all the little details. Compiler automatic catch and point out the errors made by the programmer. It can be easy to correct error and corrected by the programmer.


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Lower program preparation cost rather than assembly language and machine language. A Program written in high level language are easier to maintain than assembly language or machine language programs. Disadvantage:- A program written in assembly language or machine language is more efficient than one written in high-level language.

3. Operating System What need of operating system? OR Give definition of operating system Op. system is the integrated set of H.W. /S.W. programmers that controls the resources (CPU, memory, I/O, etc) of computer system and supports the activities of a computer system. It is designed to support the activities of computer installation. It is used for making a computer system convenient to use. It provides all the hardware facilities to user but it hides details of hardware resources from the user. It managing all the resource of computer system.

Users

Other Sy. S.W. & Application programs

Operating System

Computer Hardware

The following are the reason why the operating system is need:: 1. Process Management:- It takes care of ‘creation and deletion of processes’ and scheduling of various system resources to different process requesting them. 2. Memory Management:- It takes care of the allocation and declaration of memory space to the various programs in need of disk resources.


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3. File Management:- It takes care of file related activities such as organization, storing, naming, sharing and protection of file. 4. Security Management:- It protects the resources and information of computer system against destruction (damage) and unauthorized access. 5. Command Interpretation:- It takes care of interpreting user commands and directing the system resources to handle the request. 6. I/O Management:- It handles the I/O operation of the process. 7. Job Priority:- It handles job performing sequence. Various types of operating system:: 1. Batch Operating System (Batch Processing):- Batch Operating system/Batch Processing is known as serial, sequential off line, or stacked job processing. When batches of programs have been collected, the operator loads this batch of programs into the computer at one time, where they are executed one after another. The operator retrieves the printed outputs. Scheduling of batch system is very simple. Jobs are typically processed in the order of submission, that is, first come, first served based. Memory management in batch system is also simple. Memory is usually divided into two areas. Batch system often provides simple program-controlled method of I/O and simple forms of file management. This OS useful in payroll or preparation of customer statements where it is not necessary to update information (records) on daily basis. Advantages:- After input process is over, while processing is going on, user can attend other jobs. This OS is less complicated. Disadvantages:- Difficult to provide priority scheduling. Turn around time is very long. It results of an individual program or minute details are required, you have to wait till entire batch is processed. Access to one program is not possible. It is not very convenient for program development.


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2. Multiprogramming Operating System :- OS, which can handle more then one program in main memory at a time, are called Multiprogramming OS. In multiprogramming two or more programs are resides in main memory and it execute them concurrently. The CPU switches from one program to another immediately. The main advantage of this operating system is The CPU can allocate time to several program instead of remaining idle when one program is busy with I/O operation. When one program is waiting for I/O transfer, there is another program ready to utilize the CPU, thus it is possible for several users to share the time of the CPU. In this OS all the programs appear to be processed simultaneously but actually each program gets turn for processing. So at a time only one program has control of the CPU and is executing instructions. Advantages:- Many programs can run simultaneously. Time is not wasted in switching from one program to other. Maximum utilization of resources. Important and short job need not wait for a batch. Disadvantages:- OS is more complicated as multiple programs are to be handled together. Job of resource management and memory management increases. Large main memory required. Computer designed for multiprogramming must provide some type of memory 3. Time Sharing Operating System:- A Time shared OS allows a number of users to simultaneously use a computer. The primary objective of a time-shared operating system is to provide fast response to each user of the computer. The basic idea of behind of time sharing system is to allow all user programs to have a brief share of the CPU time in turn. Each user program, starting from first and proceeding through the last, is allocated a very short period of CPU time one by one. This short period of time during which user gets the attention of CPU is known as a “Time slice” or “Time slot” and it is of the order of the 10 to 20 milliseconds. Like a multiprogramming system, in this system also only one program can be in control of CPU at any given time. Because of limited main memory, it is not possible to keep the programs of all the users simultaneously in the main memory.


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Feature of this system:- Processing time is divided among various programs in time slice. Each program is given control of CPU only for one, as per turn. Sharing single computer by different users simultaneously. Advantages:- Turnaround time negligible. Computing cost is very less. All programs get equal attention and small programs get over fast. Reduce CPU idle time Avoids duplication of software. Disadvantage:- OS is more complicated and needs more space. Question of security: since hundreds of users use a timesharing system simultaneously, provision must be made to protect the security and integrity of user programs and data. Problem of Data Communications: in this OS, the users interact with the main computer system through remote terminals that require data communication facility. 4. On-Line Operating System:- On-line processing is also known as directs access or random access processing. The main feature of this system is to get immediate and direct access to record. In this system, the terminal used by the operator is connected to the main computer so that the operator can interact with the computer in a conversational mode. It is used in applications requiring fast response from the computer, e.g. Airline reservation system. Advantages:- Turnaround time is negligible. Access & retrieval of any record is quick and direct. Disadvantages:- OS is more complicated and costly Question of security Data transmission facility required 1. Real Time Operating System:- A system in which a transaction access and updates a file quickly enough to affect the original decision making is called a real time system. It is use where immediate response from the computer requires, E.g. in stock market, in product inventory etc. Real-time processing system uses on-line processing system, but an on-line system need not necessarily operate in real-time mode.


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These systems are required to be highly reliable, because even minute problems may result in fatal accident. Real time system are normally duplicated so that, in the event of a break down, back up facilities are immediately available for continuous of the system. Advantages:- Response time is very less. Data processing is very fast. Disadvantages:- A complicated system. Very expensive. Applications:- Air traffic control system. To control satellite operation. In chemical process control system.

4. Types of software packages Word Processing Packages Word processing software is used for creating documents. Drafts, letters, reports, essays, write-ups etc can be created using word processing software. Earlier, Word Star was being used widely for this purpose. Sidekick and Word Perfect are also used for drafting letters. However, the most commonly used word processing package in the world is Microsoft Word, which will be discussed later in this book. Word processing is usually what leads people to using a computer for their work. Word processors will normally have the following capabilities built into them: o Spell checking o Standard layouts for normal documents o Have some characters appear in bold print, italics, or underlined o Center lines, make text line up on the left side of the paper, or the right side of the paper o Save the document so it can be used again o Print the document. Two of the most common word processing programs are WordPerfect and Microsoft Word.


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Spread Sheet Packages Spreadsheet is a computer application that simulates a paper worksheet. It displays multiple cells that together, make up a grid consisting of rows and columns, each cell containing either alphanumeric text or numeric values. Spreadsheets are frequently used for financial information because of their ability to re-calculate the entire sheet automatically after a change to a single cell is made. Microsoft Excel Microsoft had been developing Excel on the Macintosh platform for several years to the point, where it has developed into a powerful system. A port of Excel to Windows 2.0 resulted in a fully functional Windows spreadsheet. Starting in the mid 1990s and continuing through the present, Microsoft Excel has dominated the commercial electronic spreadsheet market. The spreadsheet packages are designed to use numbers and formulas to do calculations with ease. Examples of spreadsheets include: o Budgets o Payrolls o Grade Calculations o Address Lists The most commonly used spreadsheet programs are Microsoft Excel and Lotus 123. Graphical Packages And animation, video, sound Packages:: The presentation programs can make giving presentations and using overheads easier. Other uses include: o Slide Shows o Repeating Computer Presentations on a computer monitor o Using Sound and animation in slide shows The most recognized graphic presentation programs are Microsoft PowerPoint and Harvard Graphics. Computer graphics are graphics, which are created with the aid of computers and the representation and manipulation of pictorial data by a computer. The development of computer graphics has made the application more user-friendly. It is also easier to understand and interpret many types of data. Developments in computer graphics had a profound impact on many types of media and revolutionized the animation and video game industry. The term computer graphics includes everything on computers that is not text or sound. Today nearly all computers use some graphics and users expect to control their Computer Application in Management.


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Database Packages Database programs are designed for these types of applications: o Membership lists o Student lists o Grade reports o Instructor schedules All of these have to be maintained so you can find what you need quickly and accurately. Some of the most commonly used database programs are Microsoft Access and dBase. Presentation Packages Microsoft PowerPoint is a presentation program developed by Microsoft. It is part of the Microsoft Office suite and runs on Microsoft Windows and Apple's Mac OS X computer operating systems. PowerPoint is widely used by business people, educators, students and trainers and is among the most prevalent forms of persuasive technology. Beginning with Microsoft Office 2003, Microsoft revised the branding to emphasize PowerPoint's place within the office suite, calling it Microsoft Office PowerPoint instead of just Microsoft PowerPoint. The current versions are Microsoft Office PowerPoint 2007 for Windows and 2008.


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1. Introduction of Different Communication methods GIS Introduction A Geographical Information System (GIS) is a system for capturing; storing, analyzing and managing data associated attributes which are specially referenced to the Earth. Different mapping technology There are three main types of computer mapping system available today: 1. Computer Aided Design and Drafting (CADD) based Computer Aided Mapping (CAM). 2. Automated Mapping and Facilities Management (AM/ FM). And 3. GIS.

5 Emerging Technologies and Virus

Topics Covered 1. Introduction of Different Communication methods

GIS GPS CDMA GSM Volte

2. Communication Devices Cell Phones Modem Infrared Bluetooth WiFi LIFI

3. Virus Introduction to virus and related terms Origin and History Types of Virus Problems and Protection from Virus

4. Cloud Computing What is Cloud Computing? Characteristic & Service Models(Iaas, Paas, Saas) Architecture Security & Privacy



All the three technologies have distinctly different characteristics and applications and no single system offers all of them. CAM and AM/FM systems do not permit special analyses. A GIS map has the capability to relate data across layers to allow special analysis. A CAM map does not have the graphical intuition of human eye. Overview GIS technology can be used for scientific investigations, resource management, asset management, Environmental impact assessment, urban planning, criminology, history, sales, marketing and logistics. For example, GIS might allow emergency planners to easily calculate emergency response times in the event of a natural disaster, GIS might be used to find wetlands that need protection from pollution, or GIS can be used by a company to site a new business to take advantage of a previously underserved market. A GIS can be used to implement “4M approach – Mapping, Monitoring, Modeling and Maintenance in any GIS application. Components of a GIS A working GIS integrates five key components:: Hardware, Software, Data, People and Methods. Applications:- GIS is powerful tool used in various area as following:: In Agriculture In Business In electric/ gas utilities In the environment (GIS is used every day to help protect the environment) In forestry In geology (Geologists use GIS, every day in a wide variety of applications) In hydrology In land use planning GPS Introduction GPS stands for Global Positioning System. Present century symbolizes gigantic strides in development in all fields. Inventions offering quick solution and completing tasks in minutes which otherwise used to consume far more time have made man’s life simpler. One such invention is that of quickly and precisely determining one’s location on Earth.



This requirement is essentially of prime importance to ships and aircrafts which are traveling and have no fixed landmarks to determine their position or location. Overview GPS is the satellite-based method of collecting 3D data for various scientific applications. It provides accurate information about position, velocity and time (PVT). This satellite-based navigation system installed and controlled by the U.S. Defense Department. There are 24 satellites in GPS, orbiting the earth at a height of about 12000 miles above us. Each of this satellite are constantly moving and making two complete orbits in less than 24 hours. The speed of satellite is 7000 miles/hour. Components of GPS GPS consist of space segment, control segment and user segment. Only user segment changes according to the requirements of application, while space and control segment remains unchanged for all applications. Applications Now a days scientist, sportsmen, farmers, soldiers, pilots, delivery drivers, sailors and people from many other walks of life are using GPS in ways that make their work more productive, safer, and sometimes even easier. Some areas of application are:: ◦ In Air Traffic control ◦ In Defense (protection) ◦ In Agriculture ◦ In Space Shuttle ◦ To find out the longitude and latitude of Particular location. ◦ In Tourism. CDMA Introduction There are three access schemes for radio systems for providing access to multiple users, there are Frequency Division Access (FDMA), Time Division Multiple Access (TDMA) and Code Division Multiple Access (CDMA). FDMA division by frequency, TDMA division by time, CDMA every communicator will be allocated the entire spectrum all of the time. CDMA is a spread – spectrum technology that allows many users to occupy the same time and frequency allocations in a given band/space.



As the name implies, CDMA assigns unique codes to each user to differentiate it from others in the same spectrum. It is a platform on which 2G and 3G advanced services are built. The rate of the spreading signal is known as the ‘chip rate’, as each bit in the spreading signal is known as ‘chip’. Benefits CDMA phones give very good cell quality and lower power consumption It provides more than ten times the capacity of the analogue cell phone system and five times the calling capacity of GSM and TDMA. It requires fewer cell sites than the GSM and TDMA digital cell phone systems. This technology provides good resistance to fading problems. It avoids interceptions. GSM Introduction Global System for Mobile communication (GSM) is a globally accepted standard for digital cellular communication. GSM is established in 1982 to create a common European mobile telephone standard, operating at 900 MHz. In GSM both signaling and speech channels are digital, and thus is considered a second generation (2G) mobile phone system. GSM is a cellular network, operates in four different frequency ranges. Most GSM networks operate in the 900 MHz or 1800 MHz bands. Some countries such as US and Canada use the 850 MHz and 1900 MHz bands because the 900 and 1800 MHz frequency bands were already allocated. There are five different cell sizes in a GSM network – macro, micro, and Pico, femto and umbrella cells. VOLTE Voice over Long-Term Evolution (VoLTE) is a standard for high-speed wireless communication for mobile phones and data terminals - including IoT devices and wearable. It is based on the IP Multimedia Subsystem (IMS) network, with specific profiles for control and media planes of voice service on LTE defined by GSMA in PRD IR.92.[1] This approach results in the voice service (control and media planes) being delivered as data flows within the LTE data bearer. This means that there is no dependency on (or ultimately, requirement for) the legacy circuit-switched voice network to be maintained. VoLTE has up to three times more voice and data capacity than 3G UMTS and up to six times more than 2G GSM. Furthermore, it frees up bandwidth because VoLTE’s packets headers are smaller than those of unoptimized VoIP/LTE.

https://en.wikipedia.org/wiki/Wireless_communication


https://en.wikipedia.org/wiki/IP_Multimedia_Subsystem

https://en.wikipedia.org/wiki/Control_plane

https://en.wikipedia.org/w/index.php?title=Media_plane&action=edit&redlink=1

https://en.wikipedia.org/wiki/LTE_%28telecommunication%29

https://en.wikipedia.org/wiki/GSMA

https://en.wikipedia.org/wiki/Voice_over_LTE#cite_note-1

https://en.wikipedia.org/w/index.php?title=Data_bearer&action=edit&redlink=1

https://en.wikipedia.org/wiki/Circuit-switched

https://en.wikipedia.org/wiki/Header_%28computing%29



2. Communication Devices Cell Phones Introduction Cellular telephone also known as mobile or cell phones are a short – range, portable electronic device used for mobile voice over a network of specialized base stations known as cell sites. They have been the most popular among all consumer electronic devices that ever invented. Today, cell phones are most common and they have become a way of life. It is basically a two – way walkie – talkie that acts like a telephone. In addition to the standard voice function of a telephone, current mobile phones may support many additional services, such for text messaging, email, packet switching for access to the Internet, gaming, Bluetooth, infrared, camera with video recorded and MMS for sending and receiving photos and video. Cellular phones originated from the concept of Radio in the year 1920. The modern cellular phone was developed in 1947 which originated from the mobile car phone. The first actual cell phone was made in 1973 by Martin Cooper of Motorola and his teammates who used the idea of the car phone and applied this technology to make a portable cell phone. The working of a cell phone is based on frequency reuse. Cell phone Network A cellular network is a radio network distributed over land areas called cells, each served by at least one fixed-location transceiver known as a cell site or base station. When joined together these cells provide radio coverage over a wide geographic area. This enables a large number of portable transceivers (e.g., mobile phones, pagers, etc.) to communicate with each other and with fixed transceivers and telephones anywhere in the network, via base stations. Modern mobile phone networks use cells because radio frequencies are a limited, shared resource. Cell-sites and handsets change frequency under computer control and use low power transmitters so that a limited number of radio frequencies can be simultaneously used by many callers with less interference. A cellular network is used by the mobile phone operator to achieve both coverage and capacity for their subscribers.



Cell phone Channel A single cell in an analog cell-phone system uses the available duplex voice channels. A cell-phone carrier typically gets 832 radio frequencies to use in a city. Each cell phone uses two frequencies per call -- a duplex channel-- so there are typically 395 voice channels per carrier. (The other 42 frequencies are used for control channels -- more on this later.) Therefore, each cell has about 56 voice channels available. In other words, in any cell, 56 people can be talking on their cell phone at one time. Analog cellular systems are considered first-generation mobile technology, or 1G. With digital transmission methods (2G), the number of available channels increases. For example, a TDMA-based digital system (more on TDMA later) can carry three times as many calls as an analog system, so each cell has about 168 channels available. Cell Frequencies The cellular frequencies are the sets of frequency ranges within the UHF (Ultra High Frequency) band that have been allocated for cellular phone use. The radio frequencies used for cellular networks differ in the Americas, Europe, and Asia. The first commercial standard for mobile connection in the United States was AMPS, which was in the 800 MHz frequency band, while in Europe, the first wide – spread automatic mobile network was based on the NMT – 450 standard, which was in the 450 MHz band. As mobile phones became more popular and affordable, mobile providers couldn’t provide service to the increasing number of customers. In the 1990s, all European countries agreed upon a common digital standard called the global system for mobile communications (GMS). Mobile networks based on different standards may use the same frequency range. This is achieving by the use of different channels to carry data. The actual frequency used by a particular phone can different from place to place, depending on the settings of the carrier’s base station. Modem The word modem means modulator –demodulator. A modem is typically used to send digital data over a phone line. A modem modulates out going digital signals from a computer or other digital device to analog.



Signals for a conventional copper twisted pair telephone line and demodulate the incoming. Analog signals and convert it in to digital signal for the digital device. Modem is actually one of the most important hardware devices used in the computer especially used for the purpose of networking of the internet. There are 3 types of modem 1. External Modem: This is the simplest type of modem to install because you don’t have to open the computer. External modems have their own power supply and connect with a cable to a computer’s serial port. The telephone line plug into a socket on the rear panel of the modem. 2. Internal Modem: Most internal modems come installed in the computer you buy. Internal modems are more directly integrated into the computer system and, therefore, do not need any special attention. Internal modems are activated when you run a communication program and are turned off when you exit the program. 3. PC Card Modem: These, modems, designed for portable computers, are the size of a credit card and fit into the PC card slot on notebook and handheld computers. These modems are removed when the modem is not needed. These types of modem are like a combination of both external and internal modem. Infrared For short distance line of sight communication Infra Red Line (IR) can be used to transmit data. The most common IR device used is the hand held remote control of consumer goods such as TV, VCR, Audio System, Air conditioners etc. IR is in the frequency range 1000 to 3000 GHz and allows high speed data communication up to around 50 Mbps over a few meters in experimental systems. The most common use is thus in Local Networks. A portable computer with an IR communication interface can communicate with a stationary computer a few meters away provided there are no walls or similar obstructions in the line of sight path.



Advantages:: The main advantage of IR is has a restricted range and thus the same frequency can be used in rooms without interference. Bluetooth Bluetooth is the technology using short range radio links, intended to replace the cables connecting portable/fixed electronic devices. Using this technology, users can have all mobile and fixed computer devices be totally coordinated. We can communicate with each other with minimal user effort. Key features of Bluetooth technology are robustness and low complexity, low power and low cost. The technology also offers wireless access to LANs, mobile phone network and the internet for a host of home appliances. It can connect up to 10 meter and other benefit is devices need not to be within line of sight and even connect through walls or other non metal objects. It is a radio based wireless technology which can share information over a range of 10 meter. Bluetooth technology enables computers, phones and peripherals to communicate with one another without cables. Advantages:- Video conferencing and video clips on cell phone is possible using this technology. Connecting devices without the need for cables. Reduced power consumption. More integrated with in laptops, mobile phones and other devices. Pico net Blue tooth devices are generally organized into groups of two to eight devices are called Pico nets. It is consisting of a single master device and one or more slave device. A device may additionally belong to more than one Pico net, either as a slave in both or as a master of one Pico net and slave in other. Wi – Fi Wi-Fi stands for wireless Fidelity and used to define any of the wireless technology. Wi - Fi is the wireless way to handle networking.



It is also known as 802.11 networking and wireless networking. The big advantage of Wi–Fi is its simplicity. We can connect computers anywhere in our home or office without the needs of wires. Using these technology computers up to 100 feet can be connected into network. Working of Wi-Fi:- Wi-Fi networks use radio technologies called IEEE 802.11 to provide secure, reliable, fast wireless connectivity. A typical Wi–Fi setup contains one or more Access Points and one or more clients. The Wi-Fi standard leaves connection criteria and roaming totally open to the client. A Wi – Fi network can be used to connect computers to each other to the internet and to wired networks. Advantages:- It is very economical networking option. Allows LANs to be deployed without cabling. Wi-Fi products are widely available in the market. Widely available in more than 250,000 public area and college campus world wide. Disadvantages:- Compared to Bluetooth, power consumption is high. It has limited range. a typical Wi-Fi home router with a stock have range of 45 meter. Wi-Fi networks that are open that can be monitored and used to read and copy data over the network. LiFI Li-Fi is the abbreviated form for Light Fidelity similar like Wi-Fi for Wireless Fidelity. Li-Fi is a wireless technology which transmits high-speed data using visible light communication (Li-Fi is the abbreviated form for Light Fidelity similar like Wi-Fi for Wireless Fidelity). Li-Fi is a wireless technology which transmits high-speed data using visible light communication. As per Lab experiments, 224 gigabits per second is the speed which has been observed for Li-Fi. Li-Fi is a subset of optical wireless communications (OWC). This technology uses light-emitting diodes (LED) to transmit data wirelessly.



Li-Fi Advantages

Li-Fi is cheaper than Wi-Fi and does not need license, it is secure means of communication as the optical waves does not pass through the walls. This works on optical level so very fast means of communication, it can transmit thousands of data streams simultaneously in parallel at higher speeds.

3. VIRUS Introduction and related Terms A VIRUS stands for Vital Information Resource under Size. A computer virus is a computer program that can copy it self and infect a computer without permission are knowledge of the user. A virus is a small piece of software that damages the real program. For example, a virus might attach itself to a program such as a spreadsheet program. A virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or the Internet, or by carrying it on a removable medium such as floppy disk, CD, or USB drive. Most personal computers are now connected to the Internet and to local area networks, facilitating the spread of malicious code. Today’s virus may also take advantage of network services such as the Word Wide Web, e – mail, instant Messaging and file sharing systems to spread out. VIRUS Origins Computer viruses are called viruses because they share some of the traits of biological viruses. A computer virus passes from computer to computer like a biological virus passes from person to person. A computer virus shares some of these traits. A computer virus must attach on top of some other program or documents in order to launch. Once it is running, it can infect other programs or documents. The analogy between computer and biological viruses stretches things a bit, but there are enough similarities that the name sticks. People write computer viruses. A person has to write the code, test it to make sure it spreads properly and then release it. Most virus creators seem to miss the point that they cause real damage to real people with their creations. Destroying everything on a person's hard disk is real damage.



Forcing a large company to waste thousands of hours cleaning up after a virus is real damage. Even a silly message is real damage because someone has to waste time getting rid of it. For this reason, the legal system is getting much harsher in punishing the people who create viruses. VIRUS History Actual history of virus started in the early 1970s when 'creeper’ virus was first detected on ARPANET, an early network used by government research groups and universities and the forerunner of the Internet. The first PC Virus in the wild was a boot sector virus called Brain, created in 1986 by the Farooq Alvi Brothers, operating out of Lahore, Pakistan. The brothers reportedly created the virus to prevent pirated copies of software they had written. Before computer networks became widespread, most viruses spread on removable media, particularly floppy disks. In the early days of the personal computer, many users regularly exchanged information and programs on floppies. Since the mid-1990s, macro viruses have become common. Most of these viruses are written in the scripting languages for Microsoft Office by infecting documents and spreadsheets. A virus may also send a web address link as an instant message to all the contacts on an infected machine. The notorious “Melissa” virus infects thousands of computers in the year 1999 with alarming speed, causing an estimated $80 million in damage. In the year 2000, the “I Love You” virus infects millions of computers virtually overnight, using a method similar to the Melissa virus. Again in the year 2000, Yahoo, eBay, Amazon, Datek and dozens of other high – profile web sites are knocked off-line for up to several hours following a series of so called distributed denial – of – service attacks. In 2001, the Code Red worm infects tens of thousands of systems running Microsoft Windows NT and Windows 2000 server software, causing an estimated $2 billion in damages. The “Klez” worm sends copies of itself to all of the e-mail address in the victim’s Microsoft Outlook directory in 2002. In the year 2003, the “Slammer” worm infects hundreds of thousands of computers in less than three hours. In 2004, the “MyDoom” worm becomes the fastest – spreading e-mail worm.



The newest species of the virus family is the cross – site scripting virus. The virus emerged from research and was academically demonstrated in 2005. TYPES OF VIRUS In computers, a virus is a program or programming code that replicates to another program, computer boot sector or document. Viruses can be transmitted as attachments to an e-mail note or in a downloaded file, or be present on a diskette or CD. Generally, there are six main types of viruses:: 1. File infectors:- This type of virus infects program files. Normally they infect executable codes, such as .COM or .EXE files. Some can infect any program for which execution is requested, including .SYS, .OVL, .PRG, and .MNU files. 2. Boot sector virus:- These virus infect executable code found in certain system areas on a disk. They attach to the Dos boot sector or diskettes or the Master Boot Record on hard disks. All floppy disks and hard disks contain a small program in the boot record that is run when the computer starts up. 3. Multi – partite viruses:- Multi – partite viruses also known as polypeptide. They infect both boot records and program files. There are particularly difficult to repair. If the boot area is cleaned, but the files are not, the boot area will be re - infected. 4. Macro viruses:- These are among the most common viruses, and they tend to do the least damage. These types of virus infect data files, such as it can infect your Microsoft Word application and typically insert unwanted words or phrases. 5. Stealth viruses :- These viruses use certain techniques to avoid detection.



They may either redirect the disk head to read another sector instead of the one in which they reside or they may alter the reading of the infected file's size shown in the directory listing. 6. E-Mail viruses :- Virus authors adapted to the changing computing environment by creating the e-mail virus. For example, the Melissa virus in March 1999 was spectacular in its attack. Melissa spread in Microsoft Word documents sent via e-mail. The “I Love You” virus, which appeared on May 4, 2000, was even simpler. It contained a piece of code as an attachment. People who double – clicked on the attachment launched the code. PROBLEMS AND PROTECTION FROM VIRUSES You can protect yourself against viruses with a few simple steps: 1. Write-protect your floppy disks when using them on other computers. 2. Remove floppy disks from drives while booting. 3. Change a setting in the BIOS that enables your PC to boot from the C-drive first. 4. Use a good anti-virus program to scan floppy disks and Pen drive before copying files. 5. Install software only from original write-protected disks with the publisher's label. 6. Do not install pirated software, especially computer games. 7. Scan files downloaded from the Internet or those transferred through a network. 8. Prepare a reuse disk with critical system files. Preferably, it should be bootable. 9. Use more secure operating system like UNIX. You never hear about viruses on these operating systems because the security features keep viruses away from your hard disk. 10. You should make sure that Macro Virus Protection is enabled in all Microsoft applications, and you should NEVER run macros in a document unless you know what they do. 11. You should never double-click on an e-mail attachment that contains an executable.



What is Cloud Computing? The terms "cloud computing" and "working in the cloud" refer to performing computer tasks using services delivered entirely over the Internet. Cloud computing is a movement away from applications needing to be installed on an individual's computer towards the applications being hosted online. (The "cloud" refers to the Internet and was inspired by technical flow charts and diagrams, which tend to use a cloud symbol to represent the Internet.)

Characteristics of Cloud Computing: To employ new technologies effectively, such as cloud computing, organizations must understand what exactly they're getting. With this in mind, the National Institute of Standards and Technology has issued its 16th and final version of The NIST Definition of Cloud Computing.

"When agencies or companies use this definition, they have a tool to determine the extent to which the information technology implementations they are considering meet the cloud characteristics and models," says Peter Mell, a NIST computer scientist who co-authored the report, also known as Special Publication 800-145.

"This is important because by adopting an authentic cloud, they are more likely to reap the promised benefits of cloud: cost savings, energy savings, rapid deployment and customer empowerment," Mell says. "And, matching an implementation to the cloud definition can assist in evaluating the security properties of the cloud."

The special publication includes the five essential characteristics of cloud computing: 1. On-demand self-service: Computing Clouds provide resources and services for users on demand. Users can customize and personalize their computing environments later on, for example, software installation, network configuration, as users usually own administrative privileges. 2. Broad network access: Capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, tablets, laptops and workstations). 3. Resource pooling: The provider's computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand. There is a sense of location independence in that the customer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state or datacenter). Examples of resources include storage, processing, memory and network bandwidth. 4. Rapid elasticity: Capabilities can be elastically provisioned and released, in some cases automatically, to scale rapidly outward and inward commensurate with demand. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be appropriated in any quantity at any time.

http://www.govinfosecurity.com/cloud-computing-c-232

http://www.govinfosecurity.com/nist-c-15

http://csrc.nist.gov/publications/nistpubs/800-145/SP800-145.pdf

http://www.govinfosecurity.com/mobility-c-212



Measured service: Cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth and active user accounts). Resource usage can be monitored, controlled and reported, providing transparency for the provider and consumer. Service Models :

SaaS: Software as a Service: For SaaS, the service provider hosts the software so you don‘t need to install it, manage it, or buy hardware for it. All you have to do is connect and use it. SaaS examples include customer relationship management (CRM) as a service; email; logistics software; order management software; payroll software; and any other software which is hosted on the internet and not physically installed on your computer. Software as a Service (SaaS) is where most businesses start their journey to cloud computing; typically starting with the remote delivery of email and online backup of business information. Software as a Service has its roots in the 1960s with ASPs (Application Service Providers) who hosted and managed specialized business applications. They reduced cost through central administration.

Benefits of SAAS

Using SaaS has proved to be beneficial in terms of scalability, efficiency and performance. Some of the benefits are listed below:

Modest software tools Efficient use of software licenses Centralized management and data Platform responsibilities managed by provider Multitenant solutions

Modest software tools

The SaaS application deployment requires a little or no client side software installation, which results in the following benefits:

No requirement for complex software packages at client side Little or no risk of configuration at client side Low distribution cost

Efficient use of software licenses

The customer can have single license for multiple computers running at different locations which reduces the licensing cost. Also, there is no requirement for license servers because the software runs in the provider's infrastructure.



Centralized management and data

The cloud provider stores data centrally. However, the cloud providers may store data in a decentralized manner for the sake of redundancy and reliability.

Platform responsibilities managed by providers

All platform responsibilities such as backups, system maintenance, security, hardware refresh, power management, etc. are performed by the cloud provider. The customer does not need to bother about them.

Multitenant solutions

Multitenant solutions allow multiple users to share single instance of different resources in virtual isolation. Customers can customize their application without affecting the core functionality.

Characteristics

Here are the characteristics of SaaS service model:

SaaS makes the software available over the Internet. The software applications are maintained by the vendor. The license to the software may be subscription based or usage based. And it is billed on recurring basis. SaaS applications are cost-effective since they do not require any maintenance at end user side. They are available on demand. They can be scaled up or down on demand. They are automatically upgraded and updated. SaaS offers shared data model. Therefore, multiple users can share single instance of infrastructure. It is not required to hard code the functionality for individual users. All users run the same version of the software.

PaaS: Platform as a Service Platform as a Service is where your operating system (such as Windows, Android, BSD, iOS, Linux, Mac OS X and IBM z/OS) is hosted in the cloud, rather than being physically installed on your own hardware. The PaaS layer offers standard remote services with which developers can build applications on top of the computer infrastructure. This might include developer tools that are offered as a service from which to build services, data access and database services, or billing services.

Benefits OF PAAS Lower administrative overhead Customer need not bother about the administration because it is the responsibility of cloud provider.



Lower total cost of ownership Customer need not purchase expensive hardware, servers, power, and data storage. Scalable solutions It is very easy to scale the resources up or down automatically, based on their demand. More current system software It is the responsibility of the cloud provider to maintain software versions and patch installations.

Characteristics

Here are the characteristics of PaaS service model:

PaaS offers browser based development environment. It allows the developer to create database and edit the application code either via Application Programming Interface or point-and-click tools. PaaS provides built-in security, scalability, and web service interfaces. PaaS provides built-in tools for defining workflow, approval processes, and business rules. It is easy to integrate PaaS with other applications on the same platform. PaaS also provides web services interfaces that allow us to connect the applications outside the platform.

IaaS: Infrastructure as a Service IaaS is where physical server space is rented and kept at a vendor‘s data warehouse. As the customer, you can install any legal software to the server and allow access to your staff and clients as you see fit. The IaaS layer offers storage and computer resources that developers and IT organizations can use to deliver business solutions. Infrastructure as a Service is the most basic form of cloud. Users rent storage space, firewalls, and any other forms of hardware and software. As the client, you are responsible for every aspect of the hardware from the operating system (OS) through to the applications that are built and run on it. Applications are developed either by the customer, or by another vendor. There are different packages offered by vendors of cloud services, offering differing levels of integration. The most basic offer just the hardware, such as server space, whilst more comprehensive offerings include service maintenance.

Benefits OF IAAS

IaaS allows the cloud provider to freely locate the infrastructure over the Internet in a cost-effective manner. Some of the key benefits of IaaS are listed below:

Full control of the computing resources through administrative access to VMs. Flexible and efficient renting of computer hardware. Portability, interoperability with legacy applications.



Full control over computing resources through administrative access to VMs

IaaS allows the customer to access computing resources through administrative access to virtual machines in the following manner:

Customer issues administrative command to cloud provider to run the virtual machine or to save data on cloud server. Customer issues administrative command to virtual machines they owned to start web server or to install new applications.

Flexible and efficient renting of computer hardware

IaaS resources such as virtual machines, storage devices, bandwidth, IP addresses, monitoring services, firewalls, etc. are made available to the customers on rent. The payment is based upon the amount of time the customer retains a resource. Also with administrative access to virtual machines, the customer can run any software, even a custom operating system.

Portability, interoperability with legacy applications

It is possible to maintain legacy between applications and workloads between IaaS clouds. For example, network applications such as web server or e-mail server that normally runs on customer-owned server hardware can also run from VMs in IaaS cloud.

Characteristics OF IAAS

Here are the characteristics of IaaS service model:

Virtual machines with pre-installed software. Virtual machines with pre-installed operating systems such as Windows, Linux, and Solaris. On-demand availability of resources. Allows to store copies of particular data at different locations. The computing resources can be easily scaled up and down.

Architecture of Cloud Computing:

Cloud Computing architecture comprises of many cloud components, which are loosely coupled. We can broadly divide the cloud architecture into two parts:

Front End Back End

Each of the ends is connected through a network, usually Internet. The following diagram shows the graphical view of cloud computing architecture:



Front End

The front end refers to the client part of cloud computing system. It consists of interfaces and applications that are required to access the cloud computing platforms, Example - Web Browser.

Back End

The back End refers to the cloud itself. It consists of all the resources required to provide cloud computing services. It comprises of huge data storage, virtual machines, security mechanism, services, deployment models, servers, etc.

Security & Privacy

Security in cloud computing is a major concern. Data in cloud should be stored in encrypted form. To restrict client from accessing the shared data directly, proxy and brokerage services should be employed.

Security Planning

Before deploying a particular resource to cloud, one should need to analyze several aspects of the resource such as:

Select resource that needs to move to the cloud and analyze its sensitivity to risk. Consider cloud service models such as IaaS, PaaS, and SaaS. These models require customer to be responsible for security at different levels of service. Consider the cloud type to be used such as public, private, community or hybrid. Understand the cloud service provider's system about data storage and its transfer into and out of the cloud.

The risk in cloud deployment mainly depends upon the service models and cloud types.



Understanding Security of Cloud

Security Boundaries

A particular service model defines the boundary between the responsibilities of service provider and customer. Cloud Security Alliance (CSA) stack model defines the boundaries between each service model and shows how different functional units relate to each other. The following diagram shows the CSA stack model:

Key Points to CSA Model

IaaS is the most basic level of service with PaaS and SaaS next two above levels of services. Moving upwards, each of the service inherits capabilities and security concerns of the model beneath. IaaS provides the infrastructure, PaaS provides platform development environment, and SaaS provides operating environment. IaaS has the least level of integrated functionalities and integrated security while SaaS has the most. This model describes the security boundaries at which cloud service provider's responsibilities end and the customer's responsibilities begin. Any security mechanism below the security boundary must be built into the system and should be maintained by the customer.

Although each service model has security mechanism, the security needs also depend upon where these services are located, in private, public, hybrid or community cloud.

Understanding Data Security

Since all the data is transferred using Internet, data security is of major concern in the cloud. Here are key mechanisms for protecting data.



Access Control Auditing Authentication Authorization

All of the service models should incorporate security mechanism operating in all above-mentioned areas.

Isolated Access to Data

Since data stored in cloud can be accessed from anywhere, we must have a mechanism to isolate data and protect it from client’s direct access.

Brokered Cloud Storage Access is an approach for isolating storage in the cloud. In this approach, two services are created:

A broker with full access to storage but no access to client. A proxy with no access to storage but access to both client and broker.

Working Of Brokered Cloud Storage Access System

When the client issues request to access data:

The client data request goes to the external service interface of proxy. The proxy forwards the request to the broker. The broker requests the data from cloud storage system. The cloud storage system returns the data to the broker. The broker returns the data to proxy. Finally the proxy sends the data to the client.

All of the above steps are shown in the following diagram:

Encryption

Encryption helps to protect data from being compromised. It protects data that is being transferred as well as data stored in the cloud. Although encryption helps to protect data from any unauthorized access, it does not prevent data loss.

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