• Mousam Pradhan

Chapter - 3 : Units of Computer

Subject: Computer Fundamentals | ▒

The study of computers involves the study of two specific units:

1. Computer Hardware

     In the computer, the physical components (which we can see, touch) that are connected together to constitute the computer system are called as computer hardware.

2. Computer Software

      Software is an asset of programs, procedures, and routines associated with the control and operation of the computer system, in fulfilling the user needs. The software also includes documentation that guides one through the operation.

The functional units of the computer's hardware are as follows :

1.  Input Unit

       An input unit performs the following functions:

         (a) It accepts (or reads) the list of instructions and data from the outside world.

         (b) It converts these instructions and data in computer acceptable format.

      (c) It supplies the converted instructions and data to the computer system for further processing.

2.  Output Unit

       An output unit performs the following functions :

       (a) It accepts the results produced by the computer which are coded form and hence cannot be easily understood by us.

         (b) It converts these coded results to human acceptable (readable) form.

         (c) It supplied the converted results to the outside world.

3. Storage Unit

      The storage unit or the primary/main storage of a computer system is designed to provide space for storing data and instructions, space for immediate results, and also space for the final result.

4.  Central Processing Unit (CPU)

       The CPU is the brain of any computer system. In a computer system, all major calculations and comparisons are made inside the CPU. The CPU is also responsible for activating and controlling the operations of other units of a computer system.

      The CPU can be further classified into two units, namely as

(a) Arithmetic and Logic Unit (ALU)

              The ALU of a computer system is the place where the actual execution of the instructions takes place during the processing operations.

(b) Control Unit (CU)

              The control unit directs and controls the activities of the internal and external devices. It interprets the instructions fetched into the computer, determines what data, if any, is needed, where it is stored, where to store the results of the operation, and sends the control signals to the devices involved in the execution of the instructions.

5. Peripheral Unit

      A peripheral device is defined as any auxiliary device such as a computer mouse or keyboard that connects to and works with the computer in some way. There are three types of peripheral devices :

(a) Input devices

(b) Output devices

(c) Input/Output devices


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