In order to use computers effectively to solve problems in our 1
environment, computer systemsare devised. A 'system' implies a good mixture of integrated parts working together to form a useful whole. Computer systems may be discussed in two parts.
 The first part is hardware- the physical, electronic, and 5
electromechanical devices that are thought of and recognized as 'computers'. The second part is software- the programs that control and coordinate the activities of the computer hardware and that direct the processing of data.
[3) Figure 5.1 shows diagrammatically the basic components of computer 10 hardware joined together in a computer system. The centerpiece is called either the computer, the processor,or usually the central processing unit (CPU).The term 'computer' usually refers to those parts of the hardware in which calculations and other data manipulations are performed, and to the internal memory in which data 15 and instructions are stored during the actual execution of programs. The various peripherals,which include inputand/or outputdevices, various secondary memorydevices, and so on, are attached to the CPU.
 Computer software can be divided into two very broad categories -
systems softwareand applications software.The former is often 20
simply referred to as 'systems'. These, when brought into internal memory, direct the computer to perform tasks. The latter may be provided along with the hardware by a systems supplier as part of a
computer product designed to answer a specific need in certain areas. These complete hardware/software products are called turnkey systems. 25
 The success or failure of any computer system depends on the skill with which the hardware and software components are selected and blended. A poorly chosen system can be a monstrosity incapable of performing the tasks for which it was originally acquired.