Question 3
(a) Explain the following terms:
- storage device;
- virtual memory.
(b)Two storage devices have capacities 2 kB and 2 MB respectively.
(i) Calculate the number of bits that each of 2 kB and 2 MB can hold.
2 kB:
2 MB: Putting the two storage devices together, calculate the total capacity in bytes.
Observation
The expected answers were:
(a) (i) storage device is a piece of computer equipment/device/hardware/peripheral which can hold /storedata/information. It can also be used to transfer data.
OR
Storage device can either be external/internal device used to hold/storedata/information for example magnetic disk, diskette, flash drive, hard drive, DVDand VCD.
OR
Storage device is a digital medium/piece of computer equipment/device/hardware capable of storing/holding data/information either temporarily or permanently
(ii) Virtual memory is the type of memory which allows a programmer to make a
memory device behave as if it has unlimited storage capacity. This supposed “extra” memory is stored on secondary storage.
OR
Virtual memory is a technique by which additional memory is created on hard disc tocompliment the activity of computer real memory
OR
It is a temporary storage used by a computer to run programs that need more memory that it has.
OR
It is a memory management technique that provides an idealized abstraction of the storage resources that are actually available on a given machine which creates the illusion to users of a very large memory.
OR
It is a memory management capability of an operating system that uses hardware and software to allow a computer to compensate for physical memory shortages by temporarily transferring data from random access memory (RAM) to disk storage.
(b) (i) Calculating number of bits held by each device
2KB
1 Kilobyte = 1024bytes
1 byte = 8bit
2 kilobytes = 2x1024x8
= 16384bits
2MB
1 Megabyte = 1024 kilobytes
1 kilobyte = 1024bytes
2 kilobytes = 2x1024x8
1 byte = 8bits
Therefore: 2MB = 2x1024x1024x8
= 16777216bits
(ii) Calculation of total capacity
To add 2Mb and 2Kb together
2Mb =2x1024x1024bytes = 2097152bytes
2Kb = 2x1024bytes = 2048bytes
Total in bytes = 2097152 + 2048bytes
=2,099,200bytes
The question tested candidates’ knowledge of computer storage device and conversion of storage units.
The chief examiner reported that candidates lacked knowledge of conversion from one unit to another.