Introduction to Computers: Inside the Computers

computer parts



The topic helps the student understand more about computer memory, the mode in which the computer saves information more so the reason why data must be kept.

In this module, we will cover the following sub-topics

  • Computer memory
  • Types of memory
  • The processor

computer memory

How information is stored in Computers. Information is stored in the computer in form of Bits. The computer system is made up of logic that works on only two states “ON” or “OFF”, which is represented by the Binary System of Numbers. It uses only two digits “0” or “1” which are used to represent information in a computer. When applied to the computer, each 0 or 1 in the binary system is called a bit which stands for binary digit. One bit cannot represent a number, letter or special character. To represent information, bits are combined into a group of eight which is called a BYTE.

EG.”A” is represented by the following byte

Types of Memory

There are three different kinds of memories;

  1. Microprocessor internal registers
  2. Main memory
  3. Secondary memory.

Internal Registers; This is fast memories within a microprocessor used as a temporary data holding area to enable CPU to manipulate data at a high speed.

Main Memory; It’s used for holding data and instructions required immediately by the CPU. There are two types of main memory.

Random Access Memory (RAM); In RAM, one can read to retrieve information and write into to store Information. It’s the memory used in large quantity in the Main memory.

Read Only Memory (ROM); ROMs are used to store permanent instructions in the computer, e.g., those that the computer use while booting (starting) up. One can read the ROM content but can’t write on it during regular computer operation.

Secondary Memory; this is the memory that is used to store backup information that is not needed by the CPU immediately.E.g Floppy Diskette, Hard Disk, Compact Disk (cd), Flash Disk, etc


NB: Information in the computer must be bucked up to avoid the loss of valuable information in case the machine broke down, or it is stolen.

The backup must be saved or kept far away from the computer room, and also several copies per every backup must be produced to be on the save side always.

The Processor

Any computer’s most essential component is the processor or CPU. It processes information and interfaces with many other system elements to retrieve data to be processed and retrieve data that has been processed.

CPU performs the following functions:

  1. Decodes and executes instructions obtained from software programs.
  2. Performs arithmetic calculations
  3. Controls and support the timing of each operation.

The speed of the CPU is the major determining factor in determining the performance of the computer.The CPU is the most expensive component on the motherboard and also a very delicate piece of equipment.

Key components found in the processor.

Arithmetic and Logic Unit (ALU); this is the brain of the microprocessor. The ALU performs basic arithmetic calculations like addition, subtraction etc

Control Unit; Controls all the functions inside the processor itself. It instructs the ALU on which arithmetic and logical operation is to be performed.

Registers; also called accumulator. It’s a place where the answers from many operations (both logical and arithmetic) are stored temporarily before being put out to the computer’s memory.


Review questions

  1. Define and give differences between RAM and ROM
  2. Briefly explain the function of the Operating System.
  3. Differentiate volatile memory from non-volatile memory
  4. Give three examples of application programs and where they can be used.


The topic has helped the student understand how the computer saves information, the reason for saving information and also clearly differentiating the different type of memories we have in computers. The student is also a stage of being able to explain what the processor is, how it works and its composition.

See Also: Part One – Introduction to Computers