Definition of computer system

Computer is an electronic device or a programmable machine that accepts and process data by following sets or sets of instructions (PROGRAM) to produce an accurate and efficient result (INFORMATION).

Since the ultimate aim of a computer is to produce information the art of computer in often referred to as information processing. The value of the computer lies on its high spread (due to its electronic nature), ability to store large amount of data, the unfailing accuracy and precision. This amount for its supremacy over manual computation.

Historical Developments

The history of members and counting was traced to be first developed by herdsmen of ancient time who sought method of taking stock of their animals using pebbles to avoid losses. They did this by presenting an animal by a pebble in them. These pebbles we are caps in the pocket when leaving for grazing in the morning and recounted in the evening when returning to ascertain that, none was missing or left behinds human being throughout the ages recognized the need to calculate and kept track on information resulting from business activities and commercial transactions.

This need become so obvious and more pressing with the growth and expansion in the different business and commercial activities. Information requirements for effective decision making becomes more complex and difficult to manage, store, retrieve when the need arise, the process as the case may be through the rudimentary techniques available to man. The above have brought above the invention and usage of simple calculating devices such as Abacus, machine Arithmetique Napien’s bone, punched cards, difference and Analytical Engine etc.

Abacus

The Abacus was the first mechanical device ever used for counting. G was invented in China and was mostly used by merchants arithmetic purposes. It contains beads strung on wires. The beats are manipulated is performed arithmetic operations. The Abacus is being used in certain businesses, commercial transactions, nursery schools and elementary schools, where pupils are learning arithmetic.

Limitations

1. It did not posses the capacity for the mathematical operations of multiplication and division.
2. It did not posses the stored program concept holding both data and instruction.
3. It’s accuracy and spread we are highly dependent on the efficiency of the operators.

Machine Arithmetique

This machine was invented in 1642 by Blaise Pascal it was the first practical machine after Abacus Leibenitz, who wire on it, late introduce the multiplication and and division functions into it. The two prominent of this later invention were.

1. Carry over should be automatic
2. Multiplication should be performed by repeated additions.

Napier’s Bone (1617)

The Napier’s bone was invented by John Napier in 1617 to allow for pick and accurate multiplication and division of large members with the Napier’s bone serving as the table of logarithm, mathematical function like multiplication and division we are easy performed as addition and subtraction respectively.

There are other types of early computers namely punched card’s, difference and analytical engine.

Generations of Computers First Generation Computers (1945-1955)

The first generation of electronic computers was developed during the Second World War and was used in directing the flying of bomb and missiles. The first generation of computers includes ENIAC, EDSAC, EDVAC, and UNIVAC. They were built with based on von Neumann principle. ENIAC was built in the United States and contains 1800 valves. ENIAC is an acronym for Electronic Numerical integrator and calculator. Other first generation computers has mentioned above are:

EDSAC: Electronic delay storage automatic computer

EDVAC: Electronic discrete variable automation computer

UNIVAC: Universal accounting machine

Features

1. They were associated with vacuum tubes technology that must be hated very high temperature in order to function.
2. They used magnet drum, and Mercury lines as men memory elements. This amount to too low capacity of internal storage.
3. They were too big/huge an occupied a lot of space. A whole hall was required to install a single computer.
4. They generated a lot of heat, which made them to break down frequently.
5. It was very slow in processing data because of its limited internal storage capacity.
6. It was prone to error/mistake because instructions we are coded in machine language.
7. They have high rate of power consumption.
8. They we are equally very expensive to build and buy. It is only government establishment. University and companies that could afford to own them.

Second Generation Computers (1955-1964)

The most important future of this generation is used of transistor in place of vacuum tube or valves. William shockley invented in a drastic reduction in the size of computer.

Examples of such computers are:

1. Transistorized digital integrated computer (TRADIC).
2. Universal accounting machine (UNIVAC 11).
3. IBM 7090, IBE 7070 and IBM 1401.
4. Atlas and LEO MARK 111.

Features:

1. It was small in size and more reliable than the first generation.
2. Much lower manufacturing cost higher processing power and lower running cost.
3. This generation was programmed using high level language programming such as FORTRAN, ALGOL, COBOL, PLI. This greatly simplified computer programming.
4. It also uses ferrite cores and magnetic drums as main.

The Third Generation Computers (1964-1972)

The generation was built with integrated circuit (ICs) generally referred to as silicon chips. The silicone chips consists of several transistor formed within a single semiconductor crystal of electronic circuit. This resulted in the reduction in physical size and cause of computers. There was improvement in parking density, miniaturization and reliability in computer development. Moreover, economics of scale lead to the low cost integrated circuit computer. Logic Gates that the has equivalent of ten (10) transistors were miniaturized and packed in one silicon chips. This scale of integration determines the range and quantity of logic Gates packaged on a silicon chip.

Computer memory was made in form of disk that replaced ferrite core memory that was now used in the second generation computers. Micro programming came into widespread used. This simplified that design of CPUs and increased their flexibility.

Techniques for concurrent (parallel) processing such as pipelining multiprocessing were introduced. Effective methods for automatic sharing of facilities or resources of computer system we are developed and, incorporated into operating system. This increased the effective speed of program execution. There was the introduction of VDU terminals and emergence of software.

Examples of this generation are: IBM 360 series, CDC-6600, PDP-8.

Features

1. This generation was more reliable and more powerful than any other generation.
2. In size they were smaller, costless than other generations before it.
3. It consumes low power computer to other generation.
4. Since the size is reduced it is more durable.