This document classifies computers into four main types based on size, speed, and cost: microcomputers, minicomputers, mainframe computers, and supercomputers. Microcomputers are the smallest and are used for personal computing. Minicomputers are larger than microcomputers and are used for departmental systems and networking. Mainframe computers are very large, powerful, and used for large organizations. Supercomputers are the most powerful and used for complex calculations in fields like weather forecasting and weapons simulation.

1. AbduSalam 1
Classification Of Computers With Respect To Size
 With respect to size, speed, and cost, we can classify computers in the
following types:
 MICRO COMPTUERS
 MINI COMPUTERS
 MAINFRAME COMPUTERS
 SUPER COMPUTERS

2. AbduSalam 2
MICRO COMPUTERS
 These computers are small in size.
 A micro computer use to have Primary memory range from a few Kilobytes to
Gigabytes.
 They are usually designed for personal use therefore they are also called as Personal
Computers (i.e. PC).
 These computers can easily be accommodated on the top of a desk due to their small
size and hence are also called as DESKTOP computers.
 There is another kind of Micro Computer which can easily be placed on the lap and such
computer is called as Laptops. These Laptops can be easily carried in a small briefcase.
 Micro Computers are highly flexible. These are also called CHIP Computers because its
entire circuitry is fabricated on a single chip.

3. AbduSalam 3
MICRO COMPUTERS (Cont’d)
 Examples:-IBM, APPLE, COMPAC, RADIO SHACK, COMMODORE, ATARI,
 IBM compatibles:- 286,386,486,Pentium-I,Pentium-II,Pantium-III,Pentium-IV etc…
 Handheld PCs (such as PDAs) lack the power of a desktop or notebook PC, but offer
features for users who need limited functions and small size.

4. AbduSalam 4
MICRO COMPUTERS (Cont’d)
 A Multi-Core Processor is a processing system composed of two or more
independent cores. The cores are typically integrated onto a single integrated
circuit die(known as a chip multiprocessor or CMP).
 Core
 Basic processing area of a computer processor
 Die
 A die in the context of integrated circuits is a small block of semiconducting
material, on which a given functional circuit is fabricated.
 A medium-scale integrated circuit die

5. AbduSalam 5
MICRO COMPUTERS (Cont’d)
 A Dual-Core and Core 2 Duo Processor contains two cores, and a Quad-Core Processor contains
four cores.
 A Multi-core processor implements multiprocessing in a single physical package.
 Cores in a multi-core device coupled together tightly.
 Cores may or may not share caches.
 Dual Core and Core 2 Duo’s are both dual core processor.
 Core2 duo only takes advantage because
 The Core 2 Duo has the same L2 cache but it has more cache size than a Dual core. However,
 There are architectural changes to the silicon that give the Core 2 Duo more sophisticated
processing.
 The single- and dual-core models are single-die, whereas the quad-core models comprise two dies,
each containing two cores, packaged in a multi-chip module.

6. AbduSalam 6
MINI COMPUTERS
 These computers are smaller in size but larger as
compared to Micro Computers.
 Less expensive
 Primary memory is usually in GIGA Bytes
 Designed for the computerization of scientific
research data.
 Mini computer usually fills a small shelf because it
includes many types of peripheral equipment
attached to it.
 Disks are used for secondary storage
 Support up to hundred’s of users at a time.
 Examples: - PRIME-9755,VAX-8650,IBM SYSTEM-
36 etc…
 Application :- Departmental systems (Network
Servers)

7. AbduSalam 7
MAINFRAME COMPUTERS
 These computers are very powerful.
 Large in size, large in memory and powerful.
 Mainframe computers are also capable of connecting terminals with it.
 These computers are used in networked environment and mainly as network servers.
 Mainframe computers are very expansive. They are usually designed for the
computerization of huge business organizations, universities, banks, scientific
laboratories, national and international markets.
 Multiple Input/Output devices are normally attached with a Mainframe computer.
 The secondary storage use to be in the form disks in a Mainframe computer.
 Mainframes are measured in integer operations per second or MIPS.

8. AbduSalam 8
MAINFRAME COMPUTERS (Cont’d)
 These computers also allow different users to work on it at the same time like Mini
computers but the number of users can be much more than that of the Mini computers
(upto thousand’s users can work at a time on a single Mainframe computer).
 Examples:- IBM-4381, IBM-360, ICL-2900,NEC-610 etc…

9. AbduSalam 9
SUPER COMPUTERS
 Supercomputer is a computer that is at the frontline of current processing, capacity,
particularly speed of calculation.
 Supercomputers are the most powerful computers.
 They are used for problems requiring complex calculations.
 It is not possible to consider one computer system as the most powerful, because the
power of a computer is not linear.
 Super Computers are very difficult to design, it requires lot of research and
development and at the same time they are very much expansive to manufacture.
 Presently approximately 30-50 Super Computers are sold per annum.

10. AbduSalam 10
SUPER COMPUTERS (Cont’d)
 The speed of a super computer is enormous as it was calculated at a rate of 64 billions
instruction per second, like Cray T90.
 But now,
 The speed of a supercomputer is measured in "FLOPS"
 Such as "TFLOPS" (10 power 12 FLOPS)(1,000,000,000,000 ), or "PFLOPS" (10 power15
FLOPS,) (1,000,000,000,000,000 operation per second).
 Example of floating point operation is the calculation of mathematical equations in real
numbers.
 In terms of computational ability, Supercomputers are more powerful.
 In February 2009, IBM designed supercomputer with 20 PFLOPS.
 This will be equivalent to 2 million (1,000,000) laptops (whereas Roadrunner is
comparable to a mere 100,000 laptops).

11. AbduSalam 11
SUPER COMPUTERS (Cont’d)
 Application in web services and search engines, online banking (Transaction processing),
weather forecasting, Climate Prediction (50 years in 30 days by 4.8 TFLOPS) ,
Cryptography, Nuclear weapons (test by simulations), Earthquake and structural
modeling and petroleum exploration.