GCSE (9–1) Computer Science
J277/01 Computer Systems
Time allowed: 1 hour 30 minutes
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but
... [Show More] only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
INFORMATION
• The total mark for this paper is 80.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 16 pages.
ADVICE
• Read each question carefully before you start your answer.
© OCR 2023 [601/8355/X]
DC (PQ) 325517/4
OCR is an exempt Charity
Turn over
Do not use:
• a calculator
2
© OCR 2023
1 Computers represent data in binary form.
(a) Tick (✓) one box to identify the statement about binary that is true.
Binary digits can only be the values 0, 1 and 2
The left-most bit of a binary integer has the smallest value
Binary is used because computers are made of switches that can only be on or off
The smallest whole number that can be stored in 8 bits is the number 1
[1]
(b) Complete the table by writing the missing denary, 8-bit binary or hexadecimal values.
Denary 8-bit binary Hexadecimal
00000111 7
49 31
01100110 66
244 11110100
[4]
3
© OCR 2023 Turn over
(c) Tick (✓) one box to identify the largest file size.
2000000 bytes
2300KB
200MB
0.1GB
[1]
(d) Tick (✓) two boxes to identify the two file sizes that are equal to each other.
4500000 bytes
450KB
4.5MB
0.45 GB
[1]
(e) Complete the binary addition by adding these two 8-bit binary numbers.
Show all your working.
0 1 1 1 0 0 0 1
+ 1 0 0 1 1 1 1 0
[2]
(f) Identify the binary shift that has been applied to the 8-bit binary number 10110000 to get the
result 10000000.
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...........................................................................................................................................[2]
4
© OCR 2023
2 A student is performing a range of actions on the internet using their computer.
(a) A range of protocols are used for the transmission of data by the student’s computer, and the
web servers they are accessing.
(i) Complete the table by identifying the most appropriate protocol for each of the tasks the
student is performing.
Task Protocol
Requesting to view a news webpage from a web
server
Entering a username and password to access
their bank account
Downloading a text document from a web server
Checking for new emails in their inbox
[4]
(ii) Some protocols have layers.
Give two reasons why protocols have layers.
1 ........................................................................................................................................
...........................................................................................................................................
2 ........................................................................................................................................
...........................................................................................................................................
[2]
(b) The student’s computer is part of their home Local Area Network (LAN). The LAN currently
only has wired connections.
(i) One characteristic of a LAN is that they are set up over a small geographical area.
Give one other characteristic of a LAN.
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