The Parts of a Computer System

Computers come in many varieties, from the tiny computers built into household appliances, to the astounding supercomputers that have helped scientists map the human genome. But no matter how big it is or how it is used, every computer is part of a system.

A complete computer system consists of four parts:

• Hardward
• Software
• Data
• User

Hardware - Any part of the computer you can touch. A computer's hardware consists of interconnected electronic devices that you can use to control the computer's operation, input, and output. (The everyday term device refers to any piece of hardware.)

Software - A set of instructions that makes the computer perform tasks. In other words , software tells the computer what to do. (The term program refers to any piece of software.) Some programs exist primarily for the computer's use to help it perform tasks and manage its own resources. Other types of programs exist for the user, enabling him or her to perform tasks such as creating documents.

Data - consist of individual facts or pieces of information that by themselves may not make much sense to a person. A computer's primary job is to process these tiny pieces of data in various ways, converting them into useful information.

Users - People are the computer operators, also known as users.


The Information Processing Cycle - a set of steps the computer follows to receive data, process the data according to instructions from a program, display the resulting information to the user, and store the results.

The information processing cycle has four parts, and each part involves one or more specific components of the computer:

Input - During this part of the cycle, the computer accepts data from some source, such as the user or a program, for processing.

Processing - During this part of the cycle, the computer's processing components perform actions on the data, based on instructions from the user or a program.

Output - Here, the computer may be required to display the results of its processing. For example, the results may appear as text, numbers, or a graphic on the computer's screen or as sounds from its speaker.

Storage - In this step, the computer permanently stores the results of its processing on a disk, USB, or some other kind of storage medium.


ESSENTIAL COMPUTER HARDWARE

           A computer's hardware devices fall into one of four categories.

1. Processor
2. Memory
3. Input and output
4. Storage

Processing devices: The procedure that transforms raw data into useful information is called processing. To perform this transformation, the computer uses two components the processor and memory. The processor is like the brain of the computer, it organizes and carries out instructions that come from either the user or software. Term central processing unit (CPU) refers to a computer's processor.

Memory devices: In a computer, memory is one or more sets of chips that store data and/or program instructions, either temporarily or permanently. The most common type of memory is called random access memory (RAM). RAM is like an electronic scratch pad inside the computer. RAM holds data and program instructions while the CPU works with them.


Input and Output Devices: A personal computer would be useless if you could not interact with it because the machine could not receive instructions or deliver the results of its work. Input devices accept data and instructions from the user or from another computer system (such as a computer or the Internet). Output devices return processed data to the user or to another computer system. The most common input device is the keyboard, which accepts letters, numbers, and commands from the user. The function or an output device is to present processed data to the user. The most common output devices are the monitor and the printer.

Storage: A computer can function with only processing, memory, input, and output devices. To be really useful, however, a computer also needs a place to keep program files and related data when they are not in use. The purpose of storage is to hold data permanently, even when the computer is turned off.