OCR
Oxford Cambridge and RSA
GCSE (9-1) Computer Science
Computer Systems
J277/01
Topic: Units of Data Storage
Time allowed: 15 minutes
Centre number
Candidate number
First name
Last name
INSTRUCTIONS
Use black ink.
Answer
all
the questions.
INFORMATION
The total mark for this paper is
10
.
The marks for each question are shown in brackets [ ].
Turn over
1
The list below shows different units of data storage.
Not all units are in the correct order.
Terabyte (TB) | Bit | Gigabyte (GB) | Byte | Petabyte (PB) | Nibble | Megabyte (MB) | Kilobyte (KB)
(a)
Complete the table by writing the missing units in order of size from smallest to largest.
[3]
Order
Unit Name
Smallest
Bit
Byte
Gigabyte (GB)
Largest
Petabyte (PB)
(b)
State how many bits are in a Nibble.
[1]
(c)
State how many bits are in a Byte.
[1]
2
A student is learning about data capacity.
(a)
Tick
one
box to identify the largest file size.
[1]
File Size
Tick (✓)
2 GB
200 MB
2000 KB
2 TB
(b)
Explain why data capacity is measured in multiples of 1000, but the smallest unit is a single bit (0 or 1).
Hint: Refer to how computers work.
[2]
3
Complete the following conversions.
You do not need to perform the calculation, just write the expression (e.g., 3 x 1000).
(a)
Calculate how many Megabytes (MB) are in 2 Gigabytes (GB).
[1]
Answer:
MB
(b)
Calculate how many Gigabytes (GB) are in 3 Terabytes (TB).
[1]
Answer:
GB
END OF QUESTION PAPER