The device that collects the input and sends it to the computer is called an input device. Input devices include keyboard, pointing devices, scanners, web camera, digital camera, audio and video input devices. Input devices carry out the following functions :

1. Accepts data from the outside world.
2. Converts this data into the binary form.
3. Sends data in binary form to the CPU for further processing.

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.