A computer system is a combination of all the functional components of a computer and its associated hardware that work together to accomplish one or more common goals.

A typical computer system consists of the following hardware components to accomplish the above task :

• Input devices
• Central Processing Unit
• Output devices
• Storage devices

Central Processing Unit (CPU) is the main information processor in a digital processor in a digital computer capable of executing a program. It interprets computer program instructions and processes data.

The two major sections of a CPU are :

• Arithmetic Logic Unit
• Control Unit

Random Access Memory is a high speed memory that holds a copy of the operating system, currently executing programs, and other information being processed . It is called a random-access memory because of its ability to access each bytes of data directly.

Primary memory is a computer that is directly accessible to the central processing unit of a computer. The function of primary memory is to store :

1. The operating system programs that manage the operations of the computer.
2. The application program that is being used at the time.
3. The data that is being used by the application program.
4. The output produced by processing.

Cache memory is a high speed memory that hold frequently accessed to data or program instructions for the purpose of speeding a computer system's performance.

The system of using more than one processor to solve a particular problem at the same time is called as parallel processing.