Meanings of Computer Computer is a device that computes, especially a programmable electronic machine that performs high-speed mathematical or logical operations or that assembles, stores, correlates, or otherwise processes information. According to Collins English Dictionary, Computer is “A device, usually electronic, that processes data according to a set of instructions”. The actions carried by the computer are either arithmetic or logical in nature.
Computers are either analog or digital in nature. Computers of yesteryears were analog in nature, but modern day computers are digital in nature. Computers can be generally classified by size and power as follows, though there is considerable overlap:
Types of Computers Personal computer: A small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data. These are cost effective machines which are used for general purpose computations. 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. Minicomputer: A multi-user computer capable of supporting from 10 to hundreds of users simultaneously. It is scaled down version of main frame machines designed to meet the computing needs of small and medium enterprise (SME). HP, IBM, SUN and Dell are some of the major vendors of mini computers.
Types of Computers Mainframe: A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously. They are usually installed in very large organizations such as banks, meteorological office, defense establishments etc. These machines have proprietary hardware and software. The cost of acquisition and maintenance of these machines are high. IBM is the most popular maker of mainframe machines and some of the models are 3090, ES/9000, and S/390 Supercomputer: An extremely fast computer that can perform hundreds of millions of instructions per second. It works on massively parallel architectures interconnecting more than one processor, has large quantity of main memory and secondary storage devices. It supports multiple users, use proprietary hardware and software, need special environment for working and are very expensive in both procuring and maintaining. Supercomputers are usually used for complicated computations such as weather forecasting and other scientific research requiring massive calculations.
A computer system comprises hardware and software . A computer system processes data into information according to instructions provided by the user. Data are raw facts that need to be processed, whereas information is meaningful data. Instructions provided by the user tell the computer hardware how to perform a task are referred to as the computer software .
Computer software is often regarded as anything but hardware, meaning that the "hard" are the parts that are tangible (able to hold) while the "soft" part is the intangible objects inside the computer.
Software is made up of a group of related programs . A program is a sequence of instructions to the hardware components of a computer system to perform a specific processing task.
Software can generally be classified into application software or systems software . Application software performs general-purpose tasks for users, e.g. a payroll system, word processing, spreadsheets.
Systems software , on the other hand, runs basic computer operations, manages computer resources and allows application software to run on the computer. Systems software includes operating systems, utility programs and language translators.
A software package is software to perform a general business function, e.g. Microsoft Office . The Microsoft Office programs Word , PowerPoint , Excel and Access will be studied in details in this course.
Letters, numbers and special characters are represented within the computer system by means of binary coding schemes . Two common binary coding schemes are the ASCII-8 and EBCDIC. Following, table lists some examples of how some characters are represented using the ASCII scheme.
People are the most important part of the computer system because they design and develop computer systems, operate computer hardware, create computer software and establish procedures for carrying out tasks.
End-users , on the other hand, are people who use a computer system to help them carry out a task specific to their job or profession or just for fun. End-users need not have much technical knowledge about the computer.