Computer Organization

Computer hardware refers to the physical parts or components of a computer. The components are:Peripheralscomputer data storagemotherboard

Today, all computers are sold along with integrated hardware components, except for desktop computers.HARDWARE

INTRODUCTION In todays world, computers have become a necessity and a lot of our day-to-day operation depend upon them.

Initially, computers were called as computer systems. But in the course of time, the term system was eliminated. There are several types of computers, namely, notebook or laptop, personal, palmtop, workstation, mainframe and super computers.

COMPUTERHARDWARESOFTWAREAperipheralis a "device that is used to put information into or get information out of the computer."There are three different types of peripherals:Input, used to interact with, or send data to the computer (mouse, keyboards, etc.)Output, which provides output to the user from the computer (monitors, printers, etc.)Storage, which stores data processed by the computer (hard drives, flash drives, etc.)

PERIPHERALSINPUT PERIPHERALS Mouse

Touch pad

Touch screen Keyboard

Virtual keyboard

Projection Keyboard

Image Scanner

webcamGraphicTabletMOUSE

Amouseis apointing devicethat detectstwo-dimensionalmotion relative to a surface. This motion is typically translated into the motion of apointeron adisplay, which allows for fine control of agraphical user interface.

Touchscreen: Atouchscreenis anelectronic visual displaythat the user can control through simple ormulti-touch gesturesby touching the screen with a special stylus/pen and-or one or more fingers

Touchpad: Atouchpadortrackpadis apointing devicefeaturing atactile sensor, a specialized surface that can translate the motion and position of a user's fingers to a relative position on the operating system that is outputted to the screen.

KEYBOARD

Akeyboardis atypewriter-style device, which uses an arrangement of buttons orkeys, to act as mechanical levers or electronic switches.

Virtual Keyboard: Avirtual keyboardis a software component that allows a user to enter characters. A virtual keyboard can usually be operated with multiple input devices, which may include atouchscreen, an actualcomputer keyboardand acomputer mouse.

Projection Keyboard: Aprojection keyboardis a form of computerinput devicewhereby the image of avirtual keyboardis projected onto a surface: when a user touches the surface covered by an image of a key, the device records the corresponding keystroke.

IMAGE SCANNER

Animage scanneroften abbreviated to justscanner is a device that optically scans images, printed text,handwriting, or an object, and converts it to adigital image.

WEBCAM

Awebcamis avideo camerathat feeds orstreamsits image in real time to or through acomputertocomputer network. When "captured" by the computer, the video stream may be saved, viewed or sent on to other networks.

GRAPHIC TABLET

Agraphics tabletordigitizeris a computerinput devicethat enables a user to hand-draw images, animations and graphics, similar to the way a person draws images with a pencil and paper.

OUTPUT PERIPHERALSComputer displayPrinterProjectorSpeakerCOMPUTER DISPLAY

Amonitoror adisplayis anelectronic visual displayforcomputers. The display device in modern monitors is typically athin film transistor liquid crystal display(TFT-LCD) thin panel, while older monitors used acathode ray tube(CRT) about as deep as the screen size.

PRINTER

aprinteris aperipheralwhich makes a persistent human readable representation of graphics or text on paper or similar physical media. The two most common printer mechanisms are black and whitelaser printersused for common documents, and color ink jet printerswhich can produce high quality photograph quality output.

PROJECTOR

Aprojectororimage projectoris anopticaldevice that projects an image (or moving images) onto a surface, commonly aprojection screen.

SPEAKER

APC speakeris aloudspeakerbuilt into mostIBM PC compatiblecomputers.

Computer speakers, ormultimedia speakers, arespeakersexternal to a computer, that disable the lower fidelity built-in speaker. They often have a low-power internal amplifier.

STORAGE DEVICESFlash DriveDisk DriveCD/ DVD DriveSmartphone or Tablet storage interfaceFLASH DRIVE

AUSB flash drive, also known under a variety of other names, is adata storage devicethat includesflash memorywith an integrated Universal Serial Bus(USB) interface. USB flash drives are typically removable and rewritable, and physically much smaller than anoptical disc.

DISK DRIVE

Disk storageis a general category of storage mechanisms where data are recorded by various electronic, magnetic, optical, or mechanical changes to a surface layer of one or more rotatingdisks. A disk drive is a device implementing such a storage mechanism and is usually distinguished from the disk medium.

CD/DVD DRIVE

Anoptical disc drive(ODD) is adisk drivethat useslaserlight or electromagnetic waves as part of the process of reading or writing data to or fromoptical discs. Compact discs,DVDs, andBlu-ray discsare common types of optical media which can be read and recorded by such drives. Optical drive is the generic name; drives are usually described as "CD" "DVD", or "Blu-ray", followed by "drive", "writer", etc.

SMARTPHONE OR TABLET STORAGE INTERFACE

In case of smartphones or tablets, the storage interface is built-in and integrated with the micro processor.

Computer data storage, often calledstorageormemory, is a technology consisting ofcomputercomponents andrecording mediaused to retain digitaldata. It is a core function and fundamental component of computers.

COMPUTER DATA STORAGESTORAGERAMROMRAM

Random-access memory is a form ofcomputer data storage. A random-access memory device allowsdataitems to be read and written in roughly the same amount of time regardless of the order in which data items are accessed.Today, random-access memory takes the form ofintegrated circuits. RAM is normally associated withvolatiletypes of memory where stored information is lost if power is removed, although many efforts have been made to develop non-volatile RAM chips. Other types of non-volatile memory exist that allow random access for read operations, but either do not allow write operations or have limitations on them. These include most types ofROMand a type offlash memorycalledNOR-Flash.The two main forms of modern RAM arestatic RAM(SRAM) anddynamic RAM(DRAM). Both static and dynamic RAM are consideredvolatile, as their state is lost or reset when power is removed from the system.

ROM

Read-only memory(ROM) is a non-volatile(that is, storage that retains its data when power is removed) storagemedium used incomputersand other electronic devices. Data stored in ROM can only be modified slowly, with difficulty, or not at all, so it is mainly used to distributefirmware. In modern PCs, "ROM" is used to store the basic bootstrappingfirmwarefor the main processor, as well as the variousfirmwareneeded to internally control self-contained devices such asgraphic cards,hard disks,DVD drives,TFT screens, etc., in the system.Since ROM (at least in hard-wired mask form) cannot be modified, it is really only suitable for storing data which is not expected to need modification for the life of the device. To that end, ROM has been used in many computers to storelook-up tablesfor the evaluation of mathematical and logical functions This was especially effective whenCPUswere slow and ROM was cheap compared to RAM.

MOTHERBOARDAmainboard(sometimes alternatively known as themotherboard,system board,planar boardorlogic board,or colloquially, a mobo) is the mainprinted circuit board(PCB) found incomputersand other expandable systems. It holds many of the crucial electronic components of the system, such as thecentral processing unit(CPU) andmemory, and provides connectors for otherperipherals. Unlike abackplane, a motherboard contains significant sub-systems such as the processor and other components.

Motherboardspecifically refers to aPCBwith expansion capability and as the name suggests, this board is the "mother" of all components attached to it, which often includesound cards,video cards,network cards,hard drives, or other forms of persistent storage;TV tuner cards, cards providing extraUSBorFireWireslots and a variety of other custom components.SOFTWAREComputer softwareor simplysoftwareis any set of machine-readable instructions that directs acomputer's processor to perform specific operations. Computer software contrasts withcomputer hardware, which is the physical component of computers. Computer hardware and software require each other and neither can be realistically used without the other.Computer software includescomputer programs,librariesand their associated documentation. Software is stored incomputer memoryand is intangible, i.e. it cannot be touched.

Software can be divided into System Software Application SoftwareSystem software(systems software) iscomputer softwaredesigned to operate and control thecomputer hardwareand to provide a platform for runningapplication software. System software can be separated into two different categories, operating systems and utility software.Theoperating system(prominent examples beingz/OS,Microsoft Windows,Mac OS XandLinux), allows the parts of a computer to work together by performing tasks like transferringdatabetweenmemoryanddisksor rendering output onto adisplay device. SYSTEM SOFTWARE

Major Operating SystemsTYPES OF OSSingle- and multi-tasking

A single-tasking system can only run one program at a time, while amulti-taskingoperating system allows more than one program to be running in concurrency. This is achieved bytime-sharing, dividing the available processor time between multiple processes which are each interrupted repeatedly in time-slices by a task scheduling subsystem of the operating system. Multi-tasking may be characterized in pre-emptive and co-operative types. In pre-emptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, e.g., Solaris,Linux, as well asAmigaOSsupport pre-emptive multitasking. Cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner.16-bitversions of Microsoft Windows used cooperative multi-tasking.32-bitversions of both Windows NT and Win9x, used pre-emptive multi-tasking. Mac OS prior to OS X used to support cooperative multitasking.Single- and multi-user

Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run at the same time. Amulti-useroperating system extends the basic concept of multi-tasking with facilities that identify processes and resources, such as disk space, belonging to multiple users, and the system permits multiple users to interact with the system at the same time. Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources to multiple users.

Distributed

Adistributed operating systemmanages a group of distinct computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing. Distributed computations are carried out on more than one machine. When computers in a group work in cooperation, they form a distributed system.Templated

In an OS, distributed and cloud computing context,templatingrefers to creating a single virtual machine image as a guest operating system, then saving it as a tool for multiple running virtual machines (Gagne, 2012, p. 716). The technique is used both in virtualization and cloud computing management, and is common in large server warehouses.

Embedded

Embedded operating systemsare designed to be used inembedded computer systems. They are designed to operate on small machines like PDAs with less autonomy. They are able to operate with a limited number of resources. They are very compact and extremely efficient by design. Windows CE and Minix 3 are some examples of embedded operating systems.

Real-time

Areal-time operating systemis an operating system that guaranties to process events or data within a certain short amount of time. A real-time operating system may be single- or multi-tasking, but when multitasking, it uses specialized scheduling algorithms so that a deterministic nature of behavior is achieved. An event-driven system switches between tasks based on their priorities or external events while time-sharing operating systems switch tasks based on clock interrupts.

Microsoft introduced anoperating environmentnamedWindowson November 20, 1985 as a graphicaloperating system shell forMS-DOSin response to the growing interest ingraphical user interfaces(GUIs).Microsoft Windows(or simplyWindows) is a meta family ofgraphicaloperating systemsdeveloped, marketed, and sold by Microsoft. It consists of several families of operating systems, each of which cater to a certain sector of the computing industry. Active Windows families includeWindows NT,Windows EmbeddedandWindows Phone; these may encompass subfamilies, e.g.Windows Embedded Compact(Windows CE) orWindows Server. MICROSOFT WINDOWS

As of April 2014, the most recent versions of Windows forpersonal computers,smartphones,server computersand embedded devicesare respectivelyWindows 8.1,Windows Phone 8.1,Windows Server 2012 R2andWindows Embedded 8. A specialized version of Windows runs on theXbox Onegame console.Windows is a single- user, multi-tasking Operating System. Multilingual support is built into Windows. The language for both the keyboard and the interface can be changed through the Region and Language Control Panel. Components for all supported input languages, such asInput Method Editors, are automatically installed during Windows installation.Microsoft Windows came todominate the world'spersonal computermarket withover 90% market share, overtakingMac OS, which had been introduced in 1984. However, since 2012, it sells less thanAndroid, that became the most popular operating system in 2014, when counting on all of the computing platforms Windows runs on (same as Android), not just desktop; in 2014, selling less than a quarter of Android.

DOSDOS, short forDisk Operating System,is anacronymfor several closely relatedoperating systemsthat dominated theIBM PC compatiblemarket between 1981 and 1995, or until about 2000 including the partially DOS-basedMicrosoft Windows(95,98, andMillennium Edition).Related systems includeMS-DOS,PC DOS,DR-DOS,FreeDOS,ROM-DOS, andPTS-DOS.IBM PC DOS(and the separately soldMS-DOS) and its predecessor,86-DOS, resembledDigital Research'sCP/Mthe dominant disk operating system for 8-bitIntel 8080and Zilog Z80based microcomputers.When IBM introduced theIBM PC, built with theIntel 8088microprocessor, they needed an operating system. Seeking an 8088-compatible build of CP/M, IBM initially approached Microsoft CEOBill Gates.IBM was sent to Digital Research, and a meeting was set up. However, the initial negotiations for the use of CP/M broke down; Digital Research wished to sell CP/M on a royalty basis, while IBM sought a single license, and to change the name to "PC DOS". Digital Research founderGary Kildallrefused, and IBM withdrew.IBM again approached Bill Gates. Gates in turn approachedSeattle Computer Products. There, programmerTim Patersonhad developed a variant ofCP/M-80, intended as an internal product for testing SCP's new16-bitIntel 8086CPUcard for theS-100 bus. The system was initially named QDOS (Quick and Dirty Operating System), before being made commercially available as86-DOS. Microsoft purchased 86-DOS, allegedly for $50,000. This became Microsoft Disk Operating System, MS-DOS, introduced in 1981.Windows 95 (and Windows 98 and ME, that followed it) took over as the defaultOS kernel, though the MS-DOS component remained for compatibility. With Windows 95 and 98, the MS-DOS component could be run without starting Windows. With DOS no longer required to use Windows, the majority of PC users stopped using it directly.

APPLICATION SOFTWAREApplication softwareis a set of one or more programs designed to carry out operations for a specific application. Application software cannot run on itself but is dependent on system software to execute. Examples of application software include MS Word, MS Excel, a console game, a library management system, a spreadsheet system etc. The term is used to distinguish such software from another type ofcomputer programreferred to assystem software, which manages and integrates a computer's capabilities but does not directly perform tasks that benefit the user. The system software serves the application, which in turn serves the user.Examples of types of application software may includeaccounting software,media players, andoffice suites. Many application programs deal principally withdocuments. Applications may bebundledwith the computer and its system software or published separately, and may be coded as e.g.proprietary,open-sourceor university projects.

TYPES OF APPLICATION SOFTWAREAnapplication suiteconsists of multiple applications bundled together. They usually have related functions, features and user interfaces, and may be able to interact with each other, e.g. open each other's files.Business applicationsoften come in suites, e.g.Microsoft Office,LibreOfficeandiWork, which bundle together a word processor, a spreadsheet, etc.; but suites exist for other purposes, e.g. graphics or music.Enterprise softwareaddresses the needs of an entire organization's processes and data flows, across several departments, often in a large distributed environment. Examples includeenterprise resource planningsystems, customer relationship management (CRM) systems andsupply chain management software. Departmental Software is a sub-type of enterprise software with a focus on smaller organizations and/or groups within a large organization. (Examples include travelexpense managementand IT Helpdesk.)

Educational softwareis related to content access software, but has the content and/or features adapted for use in by educators or students. For example, it may deliver evaluations (tests), track progress through material, or include collaborative capabilities.Simulation softwaresimulates physical or abstract systems for either research, training or entertainment purposes.Media development softwaregenerates print and electronic media for others to consume, most often in a commercial or educational setting. This includes graphic-art software, desktop publishing software, multimedia development software, HTML editors, digital-animation editors, digital audio and video composition, and many others.Entertainment Softwarecan refer to video games, screen savers, programs to display motion pictures or play recorded music, and other forms of entertainment which can be experienced through use of a computing device.

The operating system itself can be considered application software when performing simple calculating, measuring, rendering, and word processing tasks not used to control hardware viacommand-line interfaceorgraphical user interface.

EPILOGUEToday, a world without computers is inconceivable. Computers have become an indispensable tool in our day-to-day affairs. The coming days will see more technologically advanced super computers which can facilitate a complete automation in our all operations.