Types of Computers
Computers can be generally classified by size and power as follows, though there is
considerable overlap:
• Mainframe: A powerful multi-user computer capable of supporting many hundreds
or thousands of users simultaneously.
o That means, they can perform different actions or ‘processes’ at the same time.
o In some ways, mainframes are more powerful than supercomputers because
they support more simultaneous programs.
o Very large and expensive computer
•Supercomputer: An extremely fast computer that can perform hundreds of millions
of instructions per second.
o Very expensive and are employed for specialized applications that require
immense amounts of mathematical calculations.
• Personal computer: A small, single-user computer based on a microprocessor. In
addition to the microprocessor, a personal computer has a keyboard for entering
o data, a monitor for displaying information, and a storage device for saving
data. Cheap and easy to use.
o Often used as stand-alone computers or in a network.
o May be connected to large mainframe computers within big companies.
• Workstation: A powerful, single-user computer. A workstation is like a personal
computer, but it has a more powerful microprocessor and a higher-quality
monitor. They have the capacity to store and process large quantities of data, but they
are only used by one person at a time. However, workstations are typically linked
together to form a computer network called a local area network, which means that
several people, such as staff in an office, can communicate with each other and share
electronic files and data.
• Minicomputer: A multi-user computer capable of supporting from 10 to hundreds
of users simultaneously. They
are mid-sized multi-processing computers.
Organisations may use a mini-computer for such tasks as managing the information
in a small financial system or maintaining a small database of information about
registrations or applications.
Microcomputers: A microcomputer is a small, relatively inexpensive computer with
a microprocessor as its central processing unit (CPU)
o A small, single-user computer based on one microprocessor.
o Microcomputers are designed to be used by individuals
Application of Computers in Solving business problems
Automated Production Systems: Many car factories are almost completely automated
and the cars are assembled by computer-controlled robots.
This automation is becoming increasingly common
throughout industry.
Design Systems: Many products are designed using CAD (Computer Aided
Design) programs to produce exact specifications and
detailed drawings on the computer before producing models
of new products
Stock Control: Stock control is ideal for automation and in many companies, it is now
completely computerized. The stock control system keeps track of the number of items
in stock and can automatically order replacement items when required.
Accounts / Payroll: In most large organizations the accounts are maintained by a
computerized system. Due to the repetitive nature of accounts a computer system is
ideally suited to this task and accuracy is guaranteed.
Computers in Education: Computer Based Training (CBT) offers a low cost
solution to training needs where you need to train a large amount of people on a single
subject.
These programs are normally supplied on CD-ROM and combine text, graphics and
sound.
Uses of Computer Computers in Daily Life, Accounts, Games, Educational, On-line
banking, Smart ID cards, Supermarkets, Working from home (Tele-working) Internet
Definitions: Data, Information and Knowledge
Data: Raw unstructured facts and figures that provide no further information
regarding patterns, context, etc.
Information: Processed data with meaning/relevance and purpose
Knowledge: Application of stored information (processed information). Knowledge
is closely linked to doing and implies know-how and understanding.
Wisdom: evaluated understanding.
THE HISTORY OF COMPUTER DEVELOPMENT
The history of computer development is often in reference to the different generations
of computing devices. Each of the five generations of computers is characterized by a
major technological development that fundamentally changed the way computers
operate. Most developments resulted in increasingly smaller, cheaper and more
powerful and efficient computing devices.
What Are the Five Generations of Computers?
The five generations of computers and the technology developments have led to the
current devices that we use today. Our journey starts in 1940 with vacuum tube
circuitry and goes to the present day — and beyond — with artificial intelligence.
First Generation (1940-1956) Vacuum Tubes
The first computers used vacuum tubes for circuitry and magnetic drums for memory,
and were often enormous, taking up entire rooms. They were very expensive to
operate and in addition to using a great deal of electricity, the first computers
generated a lot of heat, which was often the cause of malfunctions.
First generation computers relied on machine language, the lowest-level
programming language understood by computers, to perform operations, and they
could only solve one problem at a time, and it could take days or weeks to set-up a
new problem. Input was based on punched cards and paper tape, and output was
displayed on printouts.
The UNIVAC and ENIAC computers are examples of first-generation computing
devices. The UNIVAC was the first commercial computer delivered to a business
client, the U.S. Census Bureau in 1951.
Second Generation (1956-1963) Transistors
Transistors replace vacuum tubes and ushered in the second generation of computers.
The transistor was invented in 1947 but did not see widespread use in computers until
the late 1950s. The transistor was far superior to the vacuum tube, allowing computers
to become smaller, faster, cheaper, more energy-efficient and more reliable than their
first-generation predecessors.
Though the transistor still generated a great deal of heat that subjected the computer
to damage, it was a vast improvement over the vacuum tube. Second-generation
computers still relied on punched cards for input and printouts for output.
Second-generation computers moved from cryptic binary machine language to
symbolic, or assembly, languages, which allowed programmers to specify instructions
in words. High-level programming languages were also being developed at this time,
such as early versions of COBOL and FORTRAN. These were also the first computers
that stored their instructions in their memory, which moved from a magnetic drum to
magnetic core technology.
The first computers of this generation were developed for the atomic energy industry.
Third Generation (1964-1971) Integrated Circuits
The development of the integrated circuit(IC) was the hallmark of the third generation
of computers. Transistors were miniaturized and placed on siliconchips, called
semiconductors, which drastically increased the speed and efficiency of computers.
Instead of punched cards and printouts, users interacted with third generation
computers through keyboards and monitors and interfaced with an operating system,
which allowed the device to run many different applications at one time with a central
program that monitored the memory. Computers for the first time became accessible
to a mass audience because they were smaller and cheaper than their predecessors.
Fourth Generation (1971-Present) Microprocessors
The microprocessor brought the fourth generation of computers, as thousands of
integrated circuits were built onto a single silicon chip. What in the first generation
filled an entire room could now fit in the palm of the hand. The Intel 4004 chip,
developed in 1971, located all the components of the computer—from the central
processing unit and memory to input/output controls—on a single chip.
In 1981 IBM introduced its first computer for the home user, and in 1984 Apple
introduced the Macintosh. Microprocessors also moved out of the realm of desktop
computers and into many areas of life as more and more everyday products began to
use microprocessors.
As these small computers became more powerful, they could be linked together to
form networks, which eventually led to the development of the Internet. Fourth
generation computers also saw the development of GUIs, the mouse and handheld
devices.
Fifth Generation (Present and Beyond) Artificial Intelligence
Fifth generation computing devices, based on artificial intelligence, are still in
development, though there are some applications, such as voice recognition, that are
being used today. The use of parallel processing and superconductors is helping to
make artificial intelligence a reality. Quantum computation and molecular and
nanotechnology will radically change the face of computers in years to come. The goal
of fifth-generation computing is to develop devices that respond to natural language
input and are capable of learning and self-organization.
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