Definition of a Computer System
Computer is defined in so many ways by so many people based on their field of specialization. A computer is a set of interrelated and interactive devices, which uses electronic components to perform a predefined operation with accuracy. But generally, a computer system may simply be defined as an electronic device, which is capable of accepting data as input, process the data, store the data and provide a result as output in human readable form. The four basic parts of a computer are Monitor, Keyboard, Mouse and System unit.
A Brief History of Computer
Computer history and development is always traced to Charles Babbage, the Father of computers and Lady Ada Lovelace, the Mother of Programming. The computer we have come to use today perfectly without any much stress and difficulty was not invented the way we have seen but passed through series of processes and stages. There exist five generations of computer as briefly discussed below:
First Generation Computer (The Vacuum Tube Technology)
This generation of computers consists of computers developed between 1944 and 1959. ENIAC (Electronic Numerical Integrator And Calculator), EDSAC (Electronic Delay Storage Automatic Computers) and UNIVAC 1 and 11 are first generation computers. This generation of computers were very bulky, dissipates a lot of heat, some were very heavy, weighing up to 200 tons. Because of the heat, they needed special cooling system. The characteristic technology of this generation was the use of vacuum tubes as the basic building blocks for the logic parts of the computers. In terms of speed they were very slow compared with computers of later generations.
Second Generation Computer (The Transistor Technology)
The technology, which gave the distinguishing characteristics of the second -generation computers, was the transistor technology. Although this device was developed in 1948 in Bell Telephone Laboratories, and was used largely in the electronic world, it was not until 1959 that it was introduced in the manufacture of computers. These transistors replaced the bulky vacuum tubes. In addition to doing everything that the vacuum tube could do, the transistors would do so with greater reliability, with less power requirement, generate less heat, less costly to manufacture and much smaller in size. The computers developed between 1959 and 1964 are called the second-generation computers. Examples: IBM 7030, 7070, 7090, 7094, Boroughs 200 series, UNIVAC III, Honey-well 800 etc. The development of high level programming languages like FORTRAN and COBOL was another innovation brought by the second-generation computers and were 10 times faster than the first.
Third Generation Computers (Integrated Circuit Technology)
Between 1964 and 1971, the third generation computers were developed. It was the technology of integrated circuits that opened the gates to the third generation computers. In fact we can say that the integrated circuit technology really revolutionized the computer technology itself. Integrated circuits are attached to a small piece of silicon chip. This technology cam progressively from Small Scale Integration (SSI), which contained about twenty interconnected transistors and diodes, through the Medium Scale Integration (MSI) which had over hundred interconnected transistors on a single chip, to Large Scale Integration (LSI) of over tens of thousands of transistors and diodes on a single chip. The achievements of the Integrated circuit technology led to even faster, more reliable, cheap and small-sized computers, whose powers were multiple of those of the earlier generations. Indeed, this generation of computers gave birth to the mini computers, whose power of operation was more than the earlier generation, greater reliability and speed, yet was far less in size and in cost. They could do hundred times as many calculations per second and hundred times faster than their second-generation counterparts could. Examples: IBM 31360 – 31370 series, CDC 6600, 7600, Boroughs B5000 and PDP II series.
The Fourth Generation Computers (VLSIC Micro Technology
The very large-scale integrated circuit (VLSIC), made possible by the micro technology of the period 1971-1982 ushered in the fourth generation of computers. VLSIC has between 5,000 and 50,000 gates (transistors), upon which micro-processors were built. The effect of this technology was smaller and smaller but more and more powerful computers whose speed and reliability trivialized those of the earlier generations. This era also produced the micro-computers that could do the job of first generation large computers with thousand of times faster speed and affordable prices even by individual. This generation also produced a wide variety of software packages like word processing packages, graphics, games, spreadsheet packages and database management systems. Networking capabilities were also enhanced in this era. Examples of the fourth generation computers include the IBM 3033, HP 3000 mini computers, Apple II, Boroughs B7700.
Fifth Generation Computers (Era of Artificial Intelligence)
The technology of this generation of computers is characterized by Super Large Scale Integration (ULSI), Ultra Large Scale Integration (ULSI), parallel processing, Artificial Intelligence, Speech Processing, Pattern Recognition and Expert System. The distinguishing characteristics of this generation of computer are their tremendous speed and power. Continuous miniaturization of computers is the order of the day, newer, smaller, more powerful computers are seen day by day. Powerful microcomputers have today dwarfed the capability of the older days mainframe. Pentium II mother board with clock speed higher than 300 MHz and hard disk storage space over 20 Gigabytes with unbelievable capabilities, are now affordable by even low income earners. Networking ranging from local, wide area to Internets is the common features of this generation of computers and has reduced the whole world into a global village.