CLASSIFICATION OF COMPUTER
Computers are classified interns of;
·
Classification by generation.
·
Classification by size.
·
Classification by purpose.
·
Classification by type.
CLASSIFICATION BY GENERATION
First generation computer:
These
computers were developed between 1940 and 1956. Their main memory was made up
of vacuum tubes and it used punch cards and magnetic tapes for it secondary
storage, and occupies too much space. It consumes too much energy and the cost
of maintenance was high. In addition to that, it reliability was also very low.
They were mostly general computer. Example of first generation computer
includes; Electronic Numeric Integrator Automatic computer (ENIAC), Electronic
Storage Integrated Computer (EDSAC) and Universal Automatic Computer (UNIVAC-1).
Second generation computer:
The computers were developed within the period of
1956 to 1965.
It was made up of transistors which took the position
of a vacuum as the main memory. A
transistor is a small tiny electronically operated switch that can alternate
between ‘ON’ and ‘OFF’ many millions of time in one second. It has an improved
reliability, reduces cost of maintenance, occupies less space, produces less
energy and consumes lesser amount of energy.
Third generation computer:
This generation of computers was developed between
the year 1965 and 1971.
It consists of a mother board made up of silicon
(silicon chips) use to house integrated circuits (IC). It has a much improved
reliability, very high speed, consumes very small amount of energy compared to
the predecessors, much more low cost and cost of maintenance and occupies
lesser space. In this generation, the computer operates under the multi –
programming and multi – processing concept. This application were monitored and
coordinated by the memory.
Fourth generation computer:
This are the generation of computers from 1971 till
date, they are the modern day computers. They were developed as a result of an
improvement on integrated circuit. They are the first electronic computers that
used Large Scale Integrated Circuit (LSIC). In this computer, millions of
component could be fitted on a small chip. This aspect alone reduces the size
and price of the computer while increasing the power, efficiency and
reliability.
This single chips was first produced by the Intel
corporation and formed the main memory and logic circuits that perform logical
operations of the Central processing Unit (CPU) also known as microprocessor.
Storage media in this generation of computer is; diskettes, CD – ROM and also
witness an improve in input and output devices.
Fifth generation computer (Under
development):
The
idea of fifth generation computer started from 1991 through the present date
and is running to the future in this period, microprocessor with smaller size,
faster operating speed, greater processing capabilities and virtually unlimited
memory. This memory was embedded in silicon chips.
The computer will be very small in size and
will have the tremendous data processing speed and storage capacity.
CLASSIFICATION IN TERMS OF SIZES
Microcomputers: Here we have Micro computers, Mini computers,
Mainframe computers and Supper computers.
Microcomputers:
This
are the most common type of computers used in school, laboratories, offices,
etc. they can be used by only one person at a time and are generally smallest in
size. It comprises of the following;
a)
Desktop: this type of minicomputer is design for
stationary use and runs on power from an electronic outlet. The system unit is
typically separated from the screen. It usually less costly in price and maintenance.
b)
Laptop computer (Note book): These are smaller
light weight computer design for movement from place to place. It operates on
battery or A.C power. It is design with an LCD screen and the screen is
incorporated with the system unit. It also has a touchpad in the unit that
contains the processor. It cost of maintenance is higher and it is also more
expensive.
c)
Tablet computer: this is a portable computer
device having a touch sensitive screen that can be use as writing or drawing
pad. They are operated with a tablet pen and has the ability to convert
handwriting to text.
d)
Hand held computer: These includes; a palm, pocket PC and IPad.
They can comprise a small keyboard or a touch sensitive screen but exhibit much
fewer functions as compared to the others. They are also called personal
digital assistant. They can be carried on palm or pocket hence can be used as
notepad, calculator, address book and appointment book.
e)
Workstation computer: They are similar to
desktop computers but are more powerful and are usually connected to a network.
They are generally use as server machines to store and share information with
other computers on the network.
Minicomputers; it can take the size
of a refrigerator. It less expensive and can perform fewer functions compared
to Mainframe computer. The can have multiple inputs and outputs devices that
permits more than one user to work on the computer at the same time. It can
support up to 100 users or more working at the same time. Can be use by small
research organization as a network server.
Mainframe computers;
this type of computer is similar to
Minicomputers except that it is more powerful and can support many hundred of
users at a time. it has several microprocessor. It provides the function of a
centralized storage, processing and management of large amount data such as
railway and airline preservation system for the government and business
departments.
Supper computers:
This is the most powerful type of computers so far. It has many processors
and can perform billions of instruction per second. They are used when it
concerns a tremendous deal of instruction that can cause delay with the
mainframe computer. It use more advance memory such as bubble memory.
CLASSIFICATION IN TERMS OF PURPOSE
In terms of function, we have computers that are
design to carry out many different functions. They are called general purpose
computer. They are the digital computers and can perform task such as; pay
bills, manage inventories etc.
While others
are design to carryout one and only one function, they are call special purpose
computers. They include; computers design for military purposes.(tracking
airplanes and missiles). Here the sets of instruction use to perform task are
stored permanently from the time of manufacture.
CLASSIFICATION BY TYPE
In
terms of type, we have analogue, digital and hybrid computer.
Analogue computers are those that
are working on a continuous variable that is from 1 to infinity
A digital computer is that which is
working on a random discrete variable that is zeros and ones (binary digits).
Any data input into this computer is first transform into zeros and ones. They treat
text and graphics numerically.
A hybrid computer is one that
performs both analogue and digital functions, hence working on both discrete
and continuous data.
APPLICATION OF COMPUTER IN THE WORLD
BANKING:
i)
Processing, saving and current account
ii)
Foreign exchange transaction among others
iii)
Automatic Teller Machine. Abbreviated as ATM
(serve your self).
SCIENCE AND ENGINEERING:
i)
Use for complex calculations and simulation.
ii)
Computer Aided Drafting (CAD) such as ship and
aircraft design.
iii)
Inventory control and instrumentation.
iv)
Use for scientific research
COMMERCIAL ENTERPRISE:
i)
Use in the form of robots in industry to work in
furnace and manufacturing.
ii)
Here computers are also use for production
planning and scheduling requiring operation research. (Management science).
EDUCATION:
i)
Admission process
ii)
Examination handling
iii)
Computer aided teaching and learning
iv)
Online registration
v)
Online checking of result
vi)
Time table production
Others uses includes
-
Use as a means of communication
-
Use as a means for business transaction
-
Use to diagnose illness in the hospital, etc.
