Elicits the significant changes occurred in the computers from generation to generation with more emphasis on the evolution of processors
Classification of Computers
Computers designed by using the binary digital number system are called digital computers which can count and accept numbers and letters through various input devices.
- Advantage – high accuracy, most suitable for business applications,
- Disadvantage – high cost, regular reductions in price, complexity of programming
Computers which are designed considering the physical data (භෞතික දත්ත) such as voltage/වෝල්ටීයතාව, resistance/ප්රතිරෝධය, temperature/උෂ්ණත්වය, thrust/බලය, and pressure/පීඩනය are called the analog computers which process data input in a continuous form (unbroken flow of information).
- Advantage – low cost, easy of programming, uses for engineering and scientific applications.
- Disadvantage – accuracy factor, limited storage capacity, not suitable for processing business data.
A computer can also be built using some part employing digital components and some parts based on analog principles . A combination of the above two types of computers can be called hybrid computers.
- Advantage – process of both analog and digital methodologies.
Supercomputer / සුපිරි පරිගණක
- Supercomputers are used to get very special work done. A parallel functioning of several super computers can be seen mostly. These are the largest and fastest computers available but are typically not used for commercial data processing.
- Instead they are used in specialized area as in Defense, Aircraft design, computer generated movies, weather research etc.
- Supercomputer can process 64 bits or more at a time. Their processing speed ranges from 10,000 million instructions per second to 1.2 billion MIPS (depend on future technology). They can support 10,000 terminals at a time. They have huge numbers of storage and other devices connected to them.
- Eg: Top 500 :- Tianhe-2 (MilkyWay-2)-NUDT (China), Titan - Cray XK7-Cray ins. (US), Sequoia-IBM (US), K computer-Fujitsu (Japan), Mira-IBM (US)
Mainframe Computer / මහා පරිගණක
- Mainframes are less powerful and cheaper than supercomputers. These computers are very large in size and can be hardly seen today.
- They are big general purpose computers capable of handling all kinds of scientific and business applications. They are used for such application as payroll computations, accounting, business transactions, information retrieval and airline seat reservations.
- Mainframe can process several MIPS. More than 1000 remote terminals can be supported and have large on-line secondary storage capacity.
- Eg:- Mainframe Computer
Minicomputer / මධ්ය පරිගණක
- Medium size computers can be called minicomputers. This type of computer performs data processing activities in the same way as the Mainframe but not on a smaller scale. The cost of minis is lower. A mini computer can typically support 10 to 12 terminals.
- Eg:- NOVA, DEC, PDP_II and IBM series.
Microcomputer / ක්ෂුද්ර පරිගණක
- Extremely small computers can be called microcomputers which consisting of a microprocessor and associated storage and I/O devices. They are also called Personal Computer systems. Microcomputers were first available for widespread use in the 1970′s. When became possible to put entire circuitry (CPU) in a small silicon chip.