Download 2025 OCR GCSE Computer Science J277/01 Computer Systems Question paper with Mark scheme and more Exams Computer Science in PDF only on Docsity!
2025 OCR GCSE Computer Science
J277/01 Computer Systems
Complete Question paper with Marking Scheme Combined
Monday 12 May 2025 – Afternoon GCSE (9–1) Computer Science
J277/01 Computer Systems
Time allowed: 1 hour 30 minutes Do not use: • a calculator
Please write clearly in black ink. Do not write in the barcodes. Centre number Candidate number
First name(s)
IN La ST st R U na C m T e IONS
- Use black ink. You can use an HB pencil, but 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 question marked with an asterisk (*).
- This document has 16 pages. ADVICE
- Read each question carefully before you start your answer.
© OCR 2025 [601/8355/X]DC (ST) 336001/5 OCR is an exempt Charity Turn over
© OCR 2025 Turn over
(b) The student creates 10 bitmap images using a computer. Each image has a colour depth of 8-bits and a resolution of 800 × 500 pixels. (i) Define the term pixel. ......................................................................................................................................................... . .................................................................................................................................................. [1] (ii) Calculate the total file size of the 10 images in kilobytes. Show your working out. ......................................................................................................................................................... . ......................................................................................................................................................... . .........................................................................................................................................................
. File size: .......................................... kilobytes [2] (iii) State the minimum number of bits that will be needed to represent 240 different colours. .................................................................................................................................................. [1] (c) The student wants to use a secondary storage device to move their files to their home computer. Identify whether the student should use an optical or solid-state type of secondary storage device. Justify your choice. Optical or solid-state ........................................................... Justification ...................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ..........................................................................................................................................................
© OCR 2025 Turn over
.................................................................................................................................................. [4]
© OCR 2025
.................................................................................................................................................. [3]
© OCR 2025 Turn over
BLANK PAGE
DO NOT WRITE ON THIS PAGE
© OCR 2025
© OCR 2025 Turn over
© OCR 2025
[4]
© OCR 2025 Turn over
(c) The network design originally only had wired connections. The design is updated to include wireless connections via Wi-Fi. (i) Explain the benefits to the youth centre of also providing Wi-Fi connections. ......................................................................................................................................................... . ......................................................................................................................................................... . ......................................................................................................................................................... . ......................................................................................................................................................... . .......................................................................................................................................................... .................................................................................................................................................. [3] (ii) The decision to use wired and/or wireless connections can affect the performance of the network. Complete the table by explaining how each factor can affect the performance of a network. Factor How it affects performance
Bandwidth
Number of users accessing the network at the same time
............................................................................................................^ [4]
© OCR 2025 Turn over
(ii) The computers will be allocated an IPv4 address. Tick (✓) one box on each row to identify if the IPv4 address is valid or invalid.
IPv address Valid ( ✓ )
Invalid ( ✓ )
192.154.21.
[4]
(iii) When a user wants to access a website they enter the URL into the address bar of a web browser. Describe the steps that take place to convert the URL into the website’s IP address. ......................................................................................................................................................... . ......................................................................................................................................................... . ......................................................................................................................................................... . ......................................................................................................................................................... . ......................................................................................................................................................... .
© OCR 2025 Turn over
.................................................................................................................................................. [4]
© OCR 2025 Turn over
(a) Tick (✓) one box to identify the quantity of megabytes that is the same as 2 terabytes. 2000 MB 20 000 MB 200 000 MB 2 000 000 MB [1] (b) Each row in the table contains a number that is written as a denary value, 8-bit binary value and a 2-digit hexadecimal value. Some values are missing. Complete the table by writing in the missing value for each number. Denary 8-bit binary 2-digit hexadecimal
01001110 4E
215 D
[4]
© OCR 2025
(c) Complete the binary addition of these two 8-bit binary numbers. Show your working out.
[2]
(d) Tick (✓) one box to identify the result of a 2-place right binary shift on the binary number
00011101 11101110 00111011 11011100 [1] (e) Describe the binary shift that can be used to multiply any number by 8. ......................................................................................................................................................... . .................................................................................................................................................. [2]
