COA-Input-Output Interface

Input/output Interface provides a method for transferring information between processor and external input/output devices i.e., peripherals.These Input/output interface in computer system are exists in the form of special hardware component between the system bus and peripherals.This component is called “interface unit”.

A typical input-output interface between the processor and several peripherals is shown in figure below:

Here we see that each peripheral devices has an interface unit associated with it.

Now,  the question arise- why Input/output Interface is required for transferring information between processor and peripherals?

The answer is:

The Input/output Interface is required because there are exists many differences between the central computer and each peripheral while transferring information.Some major differences are:

1. Peripherals are electromechanical and electromagnetic devices and their manner of operation is different from the operation of CPU and memory, which are electronic device.Therefore, a conversion of signal values may be required.
2. The data transfer rate of peripherals is usually slower than the transfer rate of CPU, and consequently a synchronisation mechanism is needed.
3. Data codes and formats in peripherals differ from the word format in the CPU and Memory.
4. The operating modes of peripherals are differ from each other and each must be controlled so as not to disturb the operation of other peripherals connected to CPU.

These differences are resolved through input-output interface.As input-output interface(Interface Unit) contain various components, each of which performs one or more vital function for smooth transforming of information between CPU and Peripherals.