What is Digital Computer? Draw the block diagram and explain each term used in digital computer.

Digital Computer :

A digital computer is a programmable machine which read the binary instruction and processes the data which are presented in binary form.

Digital computers are different from analog computers in the sense that analog computer process the analog data. Here the term analog represents continuous data .

The digital computer takes the binary data at input, processes according to the set of instructions called program and produces the digital output.

Block Diagram of Digital Computer:

Digital Computer Diagram

Following main function units of a digital computers

1. Central Processing Unit (CPU)
2. Memory
3. Input/Output
4. Auxiliary memory

1. Central processing unit:  

The CPU is the brain of a computer where all kind of processing is done. This unit takes the input data from the input device and processes it according to the set of instruction called program.

The major function of CPU is to store the data temporarily in the registers and perform arithmetical and logical computation.

CPU has two major parts called…

1.       Arithmetic and logic unit

2.       Control unit

•    Arithmetic and logic unit: 
•     this is responsible for carrying out

(i). Arithmetical operational on data by adding, subtracting, multiplying and dividing one set with another and

(ii) .logical operations often known by comparing by using AND,OR,NOT and exclusive OR operation which is done by analyzing and evaluating data by matching it with a set of known data that are included in the program or called from the memory..

• Control Unit

this unit is mainly used for generating the electronic control signals for the synchronization of various operation .

2. Memory

1.       Memory: memory in a computer is analogous to a notebook where we may note down various things for future reference.

The memory can be classified into the following categories

·         Primary memory

·         Auxiliary or secondary memory

(i)                  Primary memory: main memory is the fastest memory in a digital computer system. This memory is primarily used to store the data and program temporarily during the execution of a program.

             

(ii)                Auxiliary or Secondary memory: secondary memory or auxiliary memory is used to store the operating system, compiler, assembler, application programs, data file etc. those are not read by CPU directly.

3. Input/Output unit: 

Data and instructions must enter the system, before any computation can be performed, 

the following function are performed by input unit.

 i).  It accepts the instructions and data from the outside world.

ii). It converts these instructions and data in computer readable form.

iii). It supplies the converted instruction and data to the computer system for further         processing.

Output unit:

the job of an output unit is just reverse of an input unit, it supplies the information obtained from processed data to the outside world.

The following functions are performed by an output unit:

1). Accept the result produced by the computer and gives to the outside world;

2). It converts this codes result to human readable form.

3). It supplies the converted result to outside world.