In order to carry out the operations mentioned in the previous section the computer allocates the task between its various functional units. The computer system is divided into three separate units for its operation. These are 1) arithmetic logical unit, 2) control unit, and 3) central processing unit.
(a) Arithmetic Logical Unit
(ALU) After you enter data through the input device it is stored in the primary storage unit. Arithmetic Logical Unit performs the actual processing of data and instruction. The major operations performed by the ALU are addition, subtraction, multiplication, division, logic and comparison. Data is transferred to ALU from storage unit when required. After processing, the output is returned back to storage unit for further processing or getting stored.
(b) Control Unit (CU)
The next component of computer is the Control Unit, which acts like the supervisor seeing whether things are done in proper fash-ion. The control unit determines the sequence in which computer programs and instructions are executed. Things like processing of programs stored in the main memory, interpretation of the instructions and issuing of signals for other units of the computer to execute them. It also acts as a switch board operator when several users access the computer simultaneously. Thereby it coordinates the activities of computer’s peripheral equipment as they perform the input and output. Therefore it is the manager of all operations mentioned in the previous section.
c) Central Processing Unit (CPU)
The ALU and the CU of a computer system are jointly known as the central processing unit. You may call CPU as the brain of any computer system. It is just like a human brain that takes all major decisions, makes all sorts of calculations and directs different parts of the computer by activating and controlling the operations.
Personal Computer Configuration
Now let us identify the physical components that make the computer work. These are
1. Central Processing Unit (CPU)
2. Computer Memory (RAM and ROM)
3. Data bus
4. Ports 5. Motherboard
6. Hard disk
7. Output Devices
8. Input Devices
All these components are inter-connected for the personal computer to work.
INTEXT QUESTIONS
1. What are the five basic operations performed by the computer?
2. What is the full form of ALU, CU and CPU.
3. Choose the correct answer.
(a) The unit which of performs arithmetic and logical operations is called
(i) ALU (ii) editing (iii) storage (iv) output
(c) The process of producing results from the data for getting useful information is called.
(i) output (ii) input (iii) processing (iv) storage