INTRODUCTION

Computer is a device capable of solving problems or manipulating data by accepting data, performing prescribed operations (mathematical or logical) on the data, and supplying the results of these operations.

Computer can also be defined as a device that takes input, processes it, and produces result (output) automatically under program control. Computer operation must follow these three stages. Namely;

            Computer performs both mathematical and logical operations. For example, a computer can be used to determine whether a business will be successful or not.

Data and Information

Data: According to ICT, Data can be referred to as raw facts and figures that have not been processed. It can be values, numbers, or instructions input by computer users. Data makes no meaning due to the fact that it has not been processed.

Information: This is referred to as raw facts and figures that have been processed.

It can be values, numbers, or instructions input by computer users. Information makes meaning due to the fact that it has been processed. It conveys more meaning because it has been processed manually, mechanically or electrically.

Information at a point in time may become a data element at another point in time. Data becomes information after processing.

History of Computers

Computer had passed through different generations. It was identified and classified into generations with respect to components used, space occupied (size), speed and year introduced.

The first traceable computer capable of automatically performing a long sequence of arithmetic and logical operations used a device called relays was designed by Professor Howard G. Aiken and Grace Hopper at Harvard University and named Mark 1.

It was used by the US Navy for gunnery and ballistic calculations, the the Relay device Mark I was in operation until 1959. 1.3.1 First Generation Computers (1946 to 1959) Vacuum tubes were used in place of relays in this generation. The size was reduced to 400m3 and processing speed was 300 milliseconds Transistors . Magnetic drum was developed during this period as a means of storing information device. Examples of computers of this generation computers were ENIAC, EDVAC UNIVAC and so on. 1.3.2 Second Generation Computer (1959 to1965) Diodes Transistors were used in place of vacuum tubes and magnetic core was used for storing information. 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. The size was reduced to 100m3 and their processing speed increased to about 12,000 microseconds. Example of this generation computer is IBM 1401. The first computers of this generation were developed for the atomic energy industry. 1.3.3 Third Generation Computer (1965 to 1970) The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers. Integrated solid state-circuit i.e. transistors and diodes were used and secondary storage was also improved. New input & Output (I/O) devices like visual display device was introduced. Magnetic ink readers and high-speed printers were introduced. 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. The space was reduced to 10m3 and processing speed increased to 43,000 nanoseconds. Example of this generation computers were IBM 360 and 370. 1.3.4 Fourth Generation Computers (1970 to date) The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. These generation computers use more advanced input and output devices such as color monitors and scanners. Size was reduced to 0.3m3 and increase in processing speed to 240,000 picoseconds was made. 1.3.5 Fifth Generation Computer This is the type of computers that will be able to copy human senses based on artificial intelligence in such a way that the computer will be able to obtain instructions from the user by speaking to the computer to complete most of the activities by using specialized equipment. Fifth generation computing devices, , are still in development, though there are some applications, such as voice recognition, that are being used today. Microprocessors 1.4 The Microprocessor Microprocessor is referred to as the main “brain” of computer. Over the years, 11different version of microprocessors had evolved. Common microprocessors include 8086, 80286, 80386, 80486, the Pentiums which is developed by Intel Co-operation. Microprocessors developed by Motorola Company include MC68020, MC68040, etc . The microprocessor determined the processing speed of any microcomputer system. 1.5 Categories of Computers Generally, computers can be classified into 3 groups viz: Examples of Analog Computers Data (Input) type i. Analog Computers ii. Digital Computers iii. Hybrid Computers Use i. General Purpose Computers ii. Special Purpose Computers Size i. Large Computers ii. Small Computers