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Chapter 1: Computer Basics.

Albert Kalim

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Computers in Our Lives

What percentage of all Americans has Internet access at home? A. 20%B. 40%C. 60%

True of False: The term ubiquitous computing refers to the trend where computers are embedded in almost any device you can think of.

Taking a class from a remote location (your home or office, for example) via a computer and the Internet is called ______________________.

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Computers in Our Lives (continued)

Computers are prevalent in the home, in the school, in the workplace, and on the go.

Most professional jobs and skilled trades heavily depend on the creation, collection, evaluation and dissemination of information.

Uses of computers include word processing, e-mail exchange, shopping, research, investments management, playing games and many other applications.

Knowledge of computers assists the consumer to purchase the right computer, save money on repairs and use the computer to maximum benefit.

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What Is a Computer and What Does It Do?

A computer is a programmable electronic device that accepts data and performs operations on that data.

Input—entering data into the computer.

Processing—performing operations on the data.

Output—presenting the results.

Storage—saving data, programs, or output for future use.

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Computers Then and Now

The computer as we know it is a fairly recent invention.

The history of computers is often referred to as generations, from pre-computers and early computers (before 1945) to fifth generation computers (now and the future).

Each new generation is characterized by a major technological development.

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Hardware The physical parts of a computer are collectively known

as hardware.

Internal hardware is located within the main box (system unit) of the computer.

External hardware is located outside the system unit and plug into connectors called ports located on the exterior of the system unit.

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Hardware (continued) An input device is used to input data into the computer.

A processing device performs calculations and comparisons necessary for processing. The main processing device is the central processing unit (CPU).

An output device presents the results to the user.

Storage devices are used to save data, programs or output.

Communication devices allow the user to communicate with others and access remote information.

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Software The programs or instructions used to tell the computer

hardware what to do.

System software allows a computer to operate and run application software.

Application software performs specific tasks or applications.

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Data and Information

Data = raw, unorganized facts. – Can be in the form of text, graphics, audio, or video.

Information = data that has been processed into a useful form.

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Computer Users and Professionals Computer users, or end users, are the people who use a

computer to obtain information.

Programmers are computer professionals whose job it is to write the programs that computers use.

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Computer Networks and the Internet A computer network links computers together so that

users can share hardware, software, and data, as well as electronically communicate with each other.

Network servers manage resources on a network.

Clients are computers on the network that access resources via the network server.

Computer networks are commonly found in businesses, schools, and homes.

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The Internet The Internet is the largest and most well-known

computer network in the world.

Individuals connect to the Internet using an Internet service provider (ISP).

E-mail and accessing Web pages are two of the most common Internet activities.

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Accessing a Network Need a modem or network adapter to connect to the

network.

Software (often built into the operating system) allows you to log on to the network and access resources.

Need an ISP and Web browser to access Internet resources.

Many networks and Internet connections require a user ID and password to log on to the network.

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Computers to Fit Every Need

Five basic categories

– Mobile devices

– Personal computers

– Midrange servers

– Mainframe computers

– Supercomputers

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Mobile Devices Very small computing devices.

Usually based on a wireless phone or pager.

Many can be used to access e-mail and Web pages.

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Personal Computers Microprocessors allow for the creation of computers

small enough to fit on a desk or lap.

PC compatible—based on the original IBM PC; typically run the Windows operating system.

Macintosh—a type of personal computer manufactured by Apple.

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Personal Computers, Cont’d. Desktop computers—small enough

to fit on or next to a desk. Can use:

– Desktop case

– Tower case

– All-in-one case

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Personal Computers, Cont’d.

Portable PCs—designed to be carried around.

– Notebook computers

– Tablet PCs (either slate or convertible)

– Handheld computers (pocket computers)

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Personal Computers (continued)

PCs designed for just network use are referred to as network computers (NCs) or thin clients.

Devices designed just for Internet access are called Internet appliances.

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Midrange Servers Medium-sized computers, also called minicomputers or

midrange computers.

Fall between microcomputers and mainframes in processing power.

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Mainframe Computers Standard choice for most large organizations.

Specialize in high-volume processing of business transactions.

Also called high-endservers or enterprise-class servers.

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Supercomputers Used for applications that have extraordinary demands

for processing power.

Offer very fast speeds and extreme degrees of accuracy.

Commonly created today by connecting hundreds of smaller computers to form a supercomputing cluster.

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Computers and Society The information age = the prominence of information

technology.

There are many benefits of a computer-oriented society, including making many tasks in our lives go much faster.

Risks include health, security, ethical, and privacy concerns.

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Chapter 2: Data Representation.

Albert Kalim

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Data and Program Representation

Computers today are mostly digital computers—devices that can only understand two states.

The two states of a digital computer are typically represented by 0s and 1s; that is, in binary form.

Computers do all processing and communications in binary form, so natural-language input and output are translated to and from binary by the computer.

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The Binary Numbering System

We normally use the decimal numbering system, which uses 10 symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, and 9).

Computers use the binary numbering system, which represents all numbers using just two symbols (0 and 1).

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Coding Systems for Text-Based Data ASCII and EBCDIC

– Fixed-length codes that can represent any single character of data as a string of eight bits.

Unicode – A longer (32 bits per character is common) code that

can be used to represent text-based data in virtually any written language.

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Coding Systems for Other Types of Data

Graphics data—often stored as a bitmap which the color to be displayed at each pixel stored in binary form.

Audio data—waveform audio is common; MP3 compression makes audio files much smaller.

Video data—requires a great deal of storage space, but can be compressed.

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Machine Language Machine language is the binary-based code used to

represent program instructions.

The basic set of machine language instructions that a CPU can understand is that CPU’s instruction set.

Most programmers rely on language translators to translate their programs into machine language for them.

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Inside the System Unit The system unit of a PC is the case that houses

processing hardware and other hardware.

All of the hardware contained within the system unit is connected to the system board or motherboard.

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CPU The CPU (central processing unit) does the vast majority of

processing for a computer.

CPUs contains a variety of circuitry and components and are connected to the motherboard.

Also called the processor or microprocessor.

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CPU (Continued) Processing speed (clock speed) is measured in

megahertz (MHz) or gigahertz (GHz) and measures the number of clock ticks per second.

A computer word is a group of bits or bytes that a CPU can manipulate at one time.

Other factors that affect the speed of the computer include the amount of RAM and cache memory, bus width, and bus speed.

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Memory: RAM

RAM (random access memory) is the computer’s main memory and is used to temporarily storage programs and data with which it is working.

RAM is volatile (erased when the power to the PC goes off).

RAM comes in a variety of types, speeds, and size. Types of RAM include:

DRAMSRAM

SDRAM

DDR SDRAMRDRAM

DDR-II SDRAM

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Memory: Other Types

Cache memory—fast memory chips located on or close to the CPU chip (L1, L2, and L3).

Registers—high speed memory built into the CPU.

ROM (read-only memory)—non-volatile chips inside which data or programs are stored.

Flash memory—non-volatile memory that can be erased and reused. Used both within the PC and for portable storage media (e.g digital cameras).

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Buses Buses are electronic paths that data travels around on a

computer system.

Internal buses move data around within the CPU.

Expansion buses establish links with peripheral devices.– ISA, PCI, AGP, USB, FireWire.

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Expansion Slots and Cards Expansion for desktop PCs.

– Expansion cards can be inserted into expansion slots on the motherboard.

– Some external devices can be plugged into existing USB or FireWire ports without adding another expansion card.

PC cards—used with notebook PCs.

Expansion for handhelds and mobile devices—can have proprietary, PC card, or SDIO slot.

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Ports Connectors to which devices can be attached.

Common ports:

Serial

Parallel

SCSI

USB

FireWire

Network

– Keyboard

– Mouse

– Monitor

– Modem

– MIDI

– Game

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How the CPU Works The CPU is a collection of electronic circuits and

components.

Impulses from an input device passes through RAM and enters the CPU via a system bus.

Within the CPU the impulses move through the circuits and components to create new impulses.

Eventually, a set of electronic impulses leaves the CPU for an output device.

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Typical CPU Components

Arithmetic/ Logic unit (ALU)

Control unit

Registers

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The System Clock and the Machine Cycle The system clock synchronizes the computer’s

operations.

The machine cycle is the series of operations involved in the execution of a single, machine-level instruction.– Fetch– Decode– Execute– Store

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Making Computers Faster Now and in the Future Speeding up your system today.

– Add more memory.

– Perform system maintenance.

– Buy a larger or second hard drive.

– Upgrade your Internet connection.

– Upgrade your video card.

– Upgrade your CPU.

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Making Computers Faster Now and in the Future (continued)

Strategies for making faster computers.

– Moving circuits closer together.

– Faster and wider buses; faster memory.

– Improved materials (copper, SOI, new materials).

– Pipelining.

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Making Computers Faster Now and in the Future, Cont’d. Strategies for making faster computers, cont’d

– Multiprocessing (multiple CPUs, each working on a different job) and parallel processing (multiple CPUs working together to make one job finish sooner).

– Hyperthreading.

– Improved instruction set design.

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Future Trends Nanotechnology—computer chips thousands of times

smaller than today’s components; built at the atomic and molecular levels.

Organic computers—computers containing organic matter (biotechnology).

Quantum computing—uses atoms or nuclei working together as quantum bits (qubits).

Optical chips—use light waves to transmit data.

3-D chips—use multiple layers of circuitry or the circuitry stands vertically.