What is a Computer???A computer is a general purpose device that canbe programmed to carry out a finite set of arithmeticor logical operations. Since a sequence ofoperations can be readily changed, the computer cansolve more than one kind of problem.Conventionally, a computer consists of at least oneprocessing element and some form of memory. Theprocessing element carries out arithmetic and logicoperations, and a sequencing and control unit thatcan change the order of operations based on storedinformation. Peripheral devices allow information tobe retrieved from an external source, and the resultof operations saved and retrieved.
Computers can be generally classified by size and poweras follows, though there is considerable overlap:Personal computer: A small, single-user computer basedon a microprocessor.Minicomputer: A multi-user computer capable ofsupporting up to hundreds of users simultaneously.Mainframe: A powerful multi-user computer capable ofsupporting many hundreds or thousands of userssimultaneously.Supercomputer: An extremely fast computer that canperform hundreds of millions of instructions per second.
Input DevicesAn input device is any peripheral (pieceof computer hardware equipment) used toprovide data and control signals toan information processing system such asa computer or other information appliance.Input and output devices make up thehardware interface between a computer anda scanner or 6DOF controller.
Output DevicesAn output device is any piece of computer hardwareequipment used to communicate the results of dataprocessing carried out by an information processingsystem (such as a computer) which converts theelectronically generated information into human-readableform. There are many input and output devices suchas multifunction printers and computer-based navigationsystems that are used for specialised or uniqueapplications. In computing, input/output, or I/O, refers to thecommunication between an information processingsystem (such as a computer), and the outside world.Inputs are the signals or data received by thesystem, and outputs are the signals or data sent from it.
Parts of a Computer!!! If you use a desktop computer, you might already know that there isnt any single part called the "computer." A computer is really a system of many parts working together. The physical parts, which you can see and touch, are collectively called hardware. (Software, on the other hand, refers to the instructions, or programs, that tell the hardware what to do.) The illustration below shows the most common hardware in a desktop computer system. Your system may look a little different, but it probably has most of these parts. A laptop computer has similar parts but combines them into a single notebook-sized package.
System Unit• The system unit is the core of a computer system. Usually its a rectangular box placed on or underneath your desk. Inside this box are many electronic components that process information. The most important of these components is the central processing unit (CPU), or microprocessor, which acts as the "brain" of your computer. Another component is random access memory (RAM), which temporarily stores information that the CPU uses while the computer is on. The information stored in RAM is erased when the computer is turned off.• Almost every other part of your computer connects to the system unit using cables. The cables plug into specific ports (openings), typically on the back of the system unit. Hardware that is not part of the system unit is sometimes called a peripheral device or device.
MonitorA monitor or display (also called screen or visual displayunit) is an electronic visual display for computers. Themonitor comprises the display device, circuitry, and anenclosure. The display device in modern monitors istypically a thin film transistor liquid crystal display(TFT-LCD) thin panel, while older monitors use a cathode raytube (CRT) about as deep as the screen size.Originally, computer monitors were used for dataprocessing while television receivers were used forentertainment. From the 1980s onwards, computers (andtheir monitors) have been used for both data processing andentertainment, while televisions have implemented somecomputer functionality. The common aspect ratio oftelevisions, and then computer monitors, has also changedfrom 4:3 to 16:9 (and 16:10).
KeyboardIn computing, a keyboard is a typewriter-style device, which uses anarrangement of buttons or keys, to act as mechanical levers or electronicswitches. Following the decline of punch cards and paper tape, interactionvia teleprinter-style keyboards became the main input device for computers.Despite the development of alternative input devices, such asthe mouse, touch screen, pen devices, character recognition and voicerecognition, the keyboard remains the most commonly used and mostversatile device used for direct (human) input into computers.
MouseA mouse is a pointing device that functions bydetecting two-dimensional motion relative to itssupporting surface. Physically, a mouse consistsof an object held under one of the usershands, with one or more buttons.The mouse sometimes features otherelements, such as "wheels", which allow the user toperform various system-dependent operations, orextra buttons or features that can add more controlor dimensional input. The mouses motion typicallytranslates into the motion of a pointer ona display, which allows for fine control ofa graphical user interface.
PrinterA printer is a peripheral which produces a text or graphics ofdocuments stored in electronic form, usually on physical printmedia such as paper or transparencies. Many printers areprimarily used as local peripherals, and are attached bya printer cable or, in most new printers, a USB cable to acomputer which serves as a document source. In addition, a few modern printers can directly interface toelectronic media such as memory cards, or to image capturedevices such as digital cameras and scanners; some printersare combined with scanners or fax machines in a singleunit, and can function as photocopiers. Printers that includenon-printing features are sometimes called multifunctionprinters (MFP), multi-function devices (MFD), or all-in-one(AIO) printers. Most MFPs include printing, scanning, andcopying among their many features.
Scanner• An image scanner—often abbreviated to just scanner— is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop (or flatbed) scanner where the document is placed on a glass window for scanning.• Hand-held scanners, where the device is moved by hand, have evolved from text scanning "wands" to 3D scanners used for industrial design, reverse engineering, test and measurement, orthotics, gaming and other applications.• Mechanically driven scanners that move the document are typically used for large-format documents, where a flatbed design would be impractical.
SpeakerComputer speakers, or multimediaspeakers, are speakers external to a computer, that disable thelower fidelity built-in speaker. They often have a low-powerinternal amplifier. The standard audio connection is a 3.5 mm(approximately 1/8 inch) stereo jack plug often colour-codedlime green (following the PC 99 standard) for computer soundcards. A plug and socket for a two-wire (signal and ground) coaxialcable is widely used to connect analogue audio and videocomponents. Rows of RCA sockets are found on the backs ofstereo amplifier and numerous A/V products. The prong is 1/8"thick by 5/16" long. A few use an RCA connector for input.There are also USB speakers which are powered from the5 volts at 500 milliamps provided by the USB port, allowingabout 2.5 watts of output power.
SoftwareComputer software is a collectionof computer program andrelated data that provides theinstructions for telling a computer whatto do and how to do it. Software refers to one or morecomputer programs and data held in thestorage of the computer for somereasons. In other words, software is a setof programs, procedures, algorithms andits documentation concerned with theoperation of a data processing system.
Types of Software There are mainly three types of Software: 1.Operating system 2.Application Software 3.Compiler Software
Operating SystemAn operating system (OS) is acollection of software thatmanages computer hardware resourcesand providescommon services for computer programs.The operating system is a vitalcomponent of the system software in acomputer system. Application programsrequire an operating system to function.Time-sharing operating systems scheduletasks for efficient use of the system andmay also include accounting for costallocation of processor time, massstorage, printing, and other resources.
Application SoftwareApplication software, also known as an application oran app, is computer software designed to help the user toperform specific tasks. Examples include enterprisesoftware, accounting software, office suites, graphicssoftware and media players.Many application programs deal principally with documents.Apps may be bundled with the computer and its systemsoftware, or may be published separately. Some users aresatisfied with the bundled apps and need never install one.Application software is contrasted with systemsoftware and middleware, which manage and integrate acomputers capabilities, but typically do not directly apply inthe performance of tasks that benefit the user. The systemsoftware serves the application, which in turn serves theuser.
Compiler SoftwareA computer cannot understand high level languages. Soto convert high level languages into machine language, theComputer needs a Translator. This Translator programis called Compiler Software.A software called the Compiler converts the Computerlanguage into machine language. For example there is a CCompiler, that converts programs written in the Clanguage to Machine language. In order to communicatewith each other we require a Translator.