Lesson Notes By Weeks and Term - Primary 3

Components of the computer system unit I&II

WEEK 7&8




Topic: Components of the computer system unit 1&11

Subbtitle: Disk Drive

Learning Objectives:

At the end of this this lesson, pupils should be able to:

  1. Tell the meaning of storage device
  2. Identify the general storage device
  3. Identify computer storage device.

Resources and materials:

Scheme of work

Online information

Instructional material:



Pictures/charts of disk drive and the types of disk drive

Building Background/connection to prior knowledge: pupils are familiar with the topic in their previous classes.


Storage devices are parts of the computer system in which we store information. The two kindsof storage devices are the

  1. main memory storage devices, and
  2. backing storage devices.

The main memory storage devices are

  1. a) Random Access Memory (RAM)

RAM stores data, programming languagesband applications software only. This storage is only for some time. It is called a temporary storage.

  1. b) Read Only Memory (ROM)

ROM stores data and system software only.The storage remains in the computer always.It is called a permanent storage.Backing storage devices provide a permanent storage for large amounts of data and programs. These data and programs can be used whenever needed. Backing storage devicesare:

  1. a) Diskettes
  2. b) Hard disk
  3. c) Compact disk (CD ROM)
  4. d) Magnetic tape
  5. e) DVD ROM
  6. f) Flash memory


A diskette stores large amounts of data and information. When this information or data is needed, we quickly get it from the diskette.

Hard disk

The hard disk stores the largest amount of data and information. It is also the fastest and easiest way of storing and getting out stored data and information.

Compact disk (CD-ROM)

Compact disks are shining, plastic materials that store large amounts of data and information.

The data and information stored in a CD-ROM are much larger than that stored in a diskette.


are now used for storing music, drawings and video films of very large amounts. Theyare also used for storing games and educational instructions.


DVD means digital versatile disk. A DVD looks like a CD and it can store larger amounts ofinformation.

Magnetic tape

The magnetic tape is also a backing storage device which stores large amounts of data and information. When needed, we get the data and information stored in a magnetic tape slowly.

Flash disk

The flash disk is very small and highly portable. stores larger quantity of data when comparedto diskettes. It also transfers the data stored in it to the computer at a very high speed.

Strategies& Activities:

Step 1 :Teacher revises the previous topic.

Step 2:Teacher introduces the new topic.

Step 3:Teacher explains the new topic.

Step 4: Teacher welcomes pupils questions.

Step 5: Teacher evaluates the pupils.

Assessment & Evaluation:

Tell the meaning of storage device

Identify the general storage device

Identify computer storage device.

WRAP UP(CONCLUSION): Teacher goes over the topic once again for better understanding.


Draw all the backing storage devices on a piece of cardboard and label them.

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