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J277 1 Paper 1 systems and data assessment practice 1

Part 6 of 7 · J277 Paper 1 · Exam transition

An independent fifty-mark assessment of systems architecture and data representation.

Students will:

  • identify CPU components and explain register roles and performance
  • apply units, fixed conversions, binary addition and shifts
  • use character codes and calculate image and sound sizes
  • explain compression choices
  • show working before teacher-released feedback

Inside: 15 text sections, 4 completion activities, 2 number activities, 15 written answers. 50 marks. Suggested time: 60–75 minutes. 2 diagrams.

Includes a teacher guide with sections, timings, misconceptions and repair routes. Objective marks and answers are held for teacher review.

Series: J277 Paper 1 · Exam transition, part 6 of 7.

Shared by Coding PathwayVerified teacher

  • 36 cells
  • About 70 minutes
  • CC BY-SA 4.0
  • Shared 26 Oct 2026

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The whole resource, exactly as a class sees it. Answers and marking are held back.

Paper 1 assessment practice 1: systems architecture and data

Answer all questions. The total mark for this worksheet is 50.

  • Work independently.
  • Do not use a calculator.
  • Show all working for calculations and binary addition.
  • Use the number of marks to judge how much detail to give.
  • Marks and marking guidance will be released by your teacher.

The questions cover OCR J277 1.1, 1.2.3, 1.2.4 and 1.2.5.

Section A: systems architecture

Question 1

The diagram shows four parts of a CPU.

Four CPU partsFour unknown CPU parts A to D have function descriptions. Main memory is outside the CPU with two-way communication.Central Processing UnitAArithmetic andlogic operationsBCoordinatesCPU activityCFrequently useddata/instructionsDSmall, faststorage locationsMain memory

Complete the labels by identifying parts A, B, C and D.

[4 marks]

Fill in the blanks4 marks
A: Answer 1

B: Answer 2

C: Answer 3

D: Answer 4

Question 2

Complete the table by identifying three registers used during the fetch-execute cycle and stating the purpose of each register.

RegisterPurpose
1
2
3

[6 marks]

Written answer6 marks

Name three registers used during the fetch-execute cycle and state the purpose of each. Write three register-purpose pairs.

Students type their answer here.

Question 3

A video-editing computer has a CPU.

(a) State three characteristics of the CPU that can affect its performance. [3]

(b) Explain how one CPU characteristic can improve the performance of the computer. [2]

Written answer3 marks

(a) A video-editing computer has a CPU. State three characteristics of the CPU that can affect its performance.

Students type their answer here.

Written answer2 marks

(b) A computer is used for video editing. Explain how changing one CPU characteristic can improve its processing performance.

Students type their answer here.

Question 4

A washing machine contains a controller that manages the wash cycle, water level and drum speed.

Explain why the controller is an embedded system.

[3 marks]

Written answer3 marks

Explain why the washing-machine controller is an embedded system.

Students type their answer here.

Section B: units and number representation

Question 5

Complete the table.

[4 marks]

Fill in the blanks4 marks
StatementMissing value
Number of bits in one nibbleAnswer 1
Number of bits in one byteAnswer 2
1000 megabytes is oneAnswer 3
1000 terabytes is oneAnswer 4

Question 6

Each row in the table contains the same number written in denary, 8-bit binary and 2-digit hexadecimal.

Complete the table.

[6 marks]

Number systems6 marks

Complete each row with the two missing number representations.

a)Denary 45. Fill in the binary and hexadecimal.

Denary
45
Binary
Hexadecimal

b)Binary 01101110. Fill in the denary and hexadecimal.

Binary
0110
1110
DenaryNot answered
Hexadecimal

c)Hexadecimal C9. Fill in the denary and binary.

Hexadecimal
C
9
DenaryNot answered
Binary

Question 7

(a) Add the two 8-bit binary numbers. Show all carries. [2]

  01011101
+ 00010111

(b) Describe the direction and number of places in a binary shift that multiplies an unsigned value by 8. Assume no significant bits are lost. [2]

Number systems2 marks

(a) Add the two 8-bit binary numbers and show all carries.

Add these 8-bit binary numbers: 01011101 + 00010111.

Carries
First number
01011101
Second number
00010111
Total
Fill in the blanks2 marks
(b) Direction: Answer 1

Number of places: Answer 2

Section C: characters, images, sound and compression

Question 8

(a) Define the term character set. [1]

Part of a character set is shown below.

CharacterDenary value
H72
I73
!33

(b) Give the denary values stored for HI!. [2]

(c) State one effect of changing from 8 bits to 16 bits for each character. [1]

Written answer1 mark

(a) Define the term character set.

Students type their answer here.

Fill in the blanks2 marks
(b) Denary values for `HI!`

H: Answer 1

I: Answer 2

!: Answer 3
Written answer1 mark

(c) State one effect of changing from 8 bits to 16 bits for each character.

Students type their answer here.

Question 9

A presentation contains six uncompressed bitmap images. Each image is 640 pixels wide and 300 pixels high. The colour depth is 8 bits.

(a) Define the term pixel. [1]

(b) Calculate the total file size of the six images in KB, using 1000 bytes = 1 KB. Show your working. [2]

(c) The colour depth is increased; pixel dimensions stay the same. Explain one effect on the image and one effect on the file. [2]

Written answer1 mark

(a) Define the term pixel in a bitmap image.

Students type their answer here.

Written answer2 marks

(b) Calculate the total file size of the six bitmap images in KB. Show your working.

Students type their answer here.

Written answer2 marks

(c) Explain one effect of increased colour depth on the bitmap image and one effect on its file.

Students type their answer here.

Question 10

The diagram shows an analogue sound wave being sampled.

A sampled sound waveA sound wave is plotted against time. Equally spaced sample points lie on the wave. The vertical axis is labelled Y.Ytime

(a) State the property represented by axis Y. [1]

(b) State the term for the number of samples taken each second. [1]

(c) An uncompressed mono recording uses a sample rate of 12,000 Hz and a bit depth of 8 bits. The recording lasts 20 seconds. Calculate its estimated file size in KB, using 1000 bytes = 1 KB. Show your working. [2]

(d) State one effect of increasing the bit depth. [1]

Written answer1 mark

(a) State the property represented by axis Y in the sound diagram.

Students type their answer here.

Written answer1 mark

(b) State the term for the number of sound samples taken each second.

Students type their answer here.

Written answer2 marks

(c) Calculate the estimated file size of the sound recording in KB. Show your working.

Students type their answer here.

Written answer1 mark

(d) A sound recording's bit depth is increased; its sample rate and duration stay the same. State one effect.

Students type their answer here.

Question 11

A school stores a master copy of a digital logo. The logo must be edited again later and must remain exactly the same after decompression.

(a) Give two reasons why the school may compress the logo file. [2]

(b) Describe one advantage of using lossless compression instead of lossy compression for the master copy. [2]

Written answer2 marks

(a) A school stores a digital logo file. Give two reasons why it may compress the file.

Students type their answer here.

Written answer2 marks

(b) A school will edit its master logo again later. Describe one advantage of lossless rather than lossy compression for this master copy.

Students type their answer here.