Basic Computer Model and different units of Computer

A. Central Processor Unit (CPU) :

Central processor unit consists of two basic blocks :

• The program control unit has a set of registers and control circuit to generate control signals.
• The execution unit or data processing unit contains a set of registers for storing data and an Arithmatic and Logic Unit (ALU) for execution of arithmatic and logical operations.

In addition, CPU may have some additional registers for temporary storage of data.

B. Input Unit :

With the help of input unit data from outside can be supplied to the computer. Program or data is read into main storage from input device or secondary storage under the control of CPU input instruction.

Example of input devices: Keyboard, Mouse, Hard disk, Floppy disk, CD-ROM drive etc.