Computer System Overview Chapter 1

Operating System Exploits the hardware resources of one or more processors Provides a set of services to system users A program that controls the execution of application programs An interface between applications and hardware

Basic Elements Processor - control the operation of the computer and perform data processing. When there is only one processor, it often referred to as the CPU Main Memory –referred to as real memory or primary memory –volatile I/O modules –secondary memory devices –communications equipment –terminals System bus –communication among processors, memory, and I/O modules

Computer Hardware Categories of computer Hardware. 1.Input devices 2.Processor 3.Output Devices 4.Secondary Storage Devices

Input Devices Input: The data or Information entered in to computer or the process of entering data or the information into the computer for processing, storage and retrieval or transmission. Ex. Keyboard, POS, Mouse, Image Scanners, Barcode etc.

Processor CPU CPU: A set of electronic circuits that perform the computer’s processing action

Output Devices The Results of inputting and Processing data and information returned by the computer,either directly to the person using the system or to secondary storage. Ex. Video display terminal, printers, speaker etc.

Secondary Storage Devices A storage medium that is external to the computer,but that can be read by the computer, a way of storing data and information outside the computer itself. Ex Hard drive, Diskettes, CD Rom etc