These devices include a keyboard which is used to type instructions into the computer; a mouse which is connected to the computer by a cable and various commands can be executed by pressing one or both buttons on the mouse, a touch screen which allows users to execute commands by touching a specific location on the screen or a voice recognition device which recognizes the sound of the end user and executes commands as spoken.
Known as central processing unit (CPU), it is a critical component where most of the analysis and decision making takes place. It consists of two main parts. The “arithmetic-logic” unit performs fundamental arithmetic operations and the “control” unit accesses the data and instructions stored in the computer and transfers them to the arithmetic-logic unit.
Storage of data and instructions can be primary or secondary. Primary storage is involved in retaining the material after it has been received from the input devices. This material is stored in the “memory” of the computer until it is needed for processing.
Secondary storage unit is primarily in the form of a “hard disk” or a “floppy disk” which is outside the control processor. The data can be permanently stored in this unit and the computer can access it and transfer it to primary storage for the purpose of processing such data.
The output devices enable the results of the analysis of the data to be transmitted to the decision maker, usually in the form of paper print-outs.
Communication devices allow users at various locations to communicate electronically and can transmit text, images, graphic, voice and video. Some basic communication devices are network terminals to input and output data, communication channels such as telephone lines and cables, and communication processors, such as “modems”. A modem is a device that converts digital signals into analog signals that are transmitted via telephone lines and reconverted back into digital signals that are read by the receiving computer.