State two disadvantages of CD-ROM over magnetic disks

Question Statistics

Source: KCSE Computer Studies 2012 - Paper 1
Question Number: 2 (b)
Marks: 2 marks
From Topic: Computer System
From Subtopic: Processing Devices (optical disks, magnetic discs)
Question Level: Form 1

What are the intentions of an examiner?

The examiner is trying to test you on the following areas;

1. Whether you are able to distinguish the CD-ROM from magnetic devices and outline disadvantages.
2. The examiner has specifically chosen the CD-ROM and not any other optical device. He/she wants you to pay total attention to the question and digout exact answers.

Are there any tricks to the question?

This question looks more direct except for the word ROM which calls for specific answers. The examiner is actually testing whether you know that the compact disk has a capacity of 700MB and these type of disks are not rewritable; actually they are called WORM-Write Once, Read Many and that magnetic media varies in capacity. From the smallest Floppy disk with a mere 1.44MB to the largest HardDisk of up to 15 Terabytes or more.
The examiner is also testing whether you know the speed of access and the speed of saving also the maintenance tasks involved of the two disks.

Are there mistakes that most students may make?

Yes of course. Most students are not keen in understanding questions, in this case, they haphazardly peruse through the question without taking time to digest the question requirements. Therefore, most students are likely to make the following mistakes;

1. Some may state advantages rather than disadvantages of the CD-ROM over magnetic media
2. Some may state disadvantages of Magnetic media instead of CD-ROM
3. Some may not even notice the word ROM or will just make an assumption and give answers that befit them rather than the question.
4. Some may not be keen on the number of marks provided thus give one disadvantage and move on, losing the other mark.

​KNEC Marking Scheme & Answers

• Fairly fragile - easy to break or scratch than magnetic disks.
• Smaller storage capacity than a hard disk.
• CD ROM have a slower data access time compared to magnetic disks.
• Takes time to save/write data than magnetic disk.
• CD ROM not re-writable.

​How Marks are awarded?

Two marks for the first two clearly stated disadvantages. [2 x 1 = 2 mks]

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