Definition of computerThe “Computer” is derivedfrom the Latin world“Compute”, which means tocalculate. So a computer isnormally considered to be acalculating device that canperform arithmetic and logicaloperations at a very fast speed. ORA computer is an electronicdevice that can acceptdata, process it and give resultsafter that processing.
Categories of computer are as following:1. Super Computer2. Mainframe Computer3. Mini Computer4. Micro Computer5. Desktop Computer6. Laptop Computer7. Handheld Computer (PDAS)8. Tablet Computer9. Single board Computer10. Work Station
Super ComputerSuper computers are the fastest,larger and the most expensivecomputer system in the world.They are used to process complexscientific jobs. They are consideredto be the resources of any nation.Super computer based on theconcept of parallel processing andcould perform one million-billionmath operations per second.Some famous super computers are:Cray xmp, Cray-3 and ETA-10.
Mainframe ComputerA computer that serves ascentral support to many usersand has the storage andcomputing capacity needed formanaging large sets of data andfiles. Mainframes often storedata on large reel-to-reelmagnetic tapes that requireextensive physical storagespace.
Mini ComputerA small computer that isintermediate between amicrocomputer and amainframe in size, speed, andcapacity, that can supporttime-sharing, and that is oftendedicated to a singleapplication.i.e PDP 11.
Micro ComputerA microcomputer is a computer witha microprocessor as its central processingunit (CPU). It includes a microprocessor,memory, and input/output (I/O) facilities.Such computers are physically smallcompared to mainframes andminicomputers, although present-daymainframes such as the IBMSystem machines use one or more custommicroprocessors as their CPUs. Manymicrocomputers (when equipped with akeyboard and screen for input and output)are also personal computers (in the genericsense).
Desktop ComputerDesktop or PCs (personalcomputer),are used by onepersonal at a time. They areusually single user machines butcan be interconnected amongthemselves to form a local areanetwork. Their speed dependsupon the processor installed in thecomputer.
Laptop ComputerA laptop computer is a personalcomputer for mobile use, usually weighing fromone to three kilogram ,depending onsize, materials and other factors A laptop has mostof the same components as a desktopcomputer, including a display, a keyboard, apointing device such as a touchpad (also known asa track pad) and/or a pointing stick, and speakersinto a single unit. A laptop is powered by mainselectricity via an AC adapter, and can be usedaway from an outlet using a rechargeable battery.Laptops are also sometimes called notebookcomputers, notebooks or netbooks.
Handheld Computers (PDAs)A mobile device (also known as ahandheld device, handheld computer orsimply handheld) is a pocket-sizedcomputing device. A smallcomputer, that literally fits in yourpalm. Compare to full-sizecomputer, palmtops are severelylimited, but they are practical for certainfunctions such as phone books andcalendars. Typically having a displayscreen with touch input and/or aminiature keyboard.
Tablet ComputerA Tablet PC is a wireless PCthat allows a user to take notesusing natural handwritingwith a stylus, digital pen, or ona touch screen. It is similar insize and thickness to a papernotepad.Example: I Pad, Galaxy Tablet.
Single board ComputerSingle-board computers (SBCs)are complete computers built ona single circuit board. The designis centered on a single or dualmicroprocessor with RAM, IOand all other features needed tobe a functional computer on theone board.
Work Station ComputerA workstation is a high-end microcomputer designed fortechnical or scientific applications.Intended primarily to be used by oneperson at a time, they are commonlyconnected to a local area network andrun multi-user operating systems. Theterm workstation has also been used torefer to a mainframecomputer terminal or a PC connectedto a network.