IGCSE Computer Science Paper 1 · Computer Systems practice papers
75 marks · 1h 45m. Each generated paper follows the 0478 Paper 1 · Computer Systems format, with the same number and style of questions as the real exam, and comes with a Cambridge-style mark scheme.
Add the 8-bit binary integers 00111111 and 01101111. Give your answer in 8-bit binary.
[2]
(b)
Describe what would happen if the result of an 8-bit addition were greater than 255.
[2]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
10101110
Working with correct carries M1 10101110 A1
2
(b)
Overflow error: the result needs more than 8 bits, so the ninth bit is lost
Overflow (error) B1 Result > 255 / needs a ninth bit that cannot be stored B1
2
Question 2Structured · 4 marks
(a)
The 7-bit data 1101011 is sent using odd parity. The parity bit is the most significant bit. Write the byte that is sent.
[1]
(b)
The byte 01101111 is received using odd parity. Explain how the receiver knows an error has occurred.
[2]
(c)
Identify one other method of error detection.
[1]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
01101011
01101011 B1
1
(b)
It has 6 ones, an even number, which does not match odd parity
Counts the number of 1s B1 Does not match agreed parity B1
2
(c)
checksum / echo check / check digit / ARQ
checksum, echo check, check digit or ARQ B1
1
Question 3Structured · 3 marks
A sound is recorded for 120 seconds at a sample rate of 32000 Hz and a sample resolution of 8 bits. Calculate the file size in mebibytes (MiB). Show your working.
[3]
Show answers and mark scheme
Part
Answer and marking points
Marks
3.66 MiB
32000 × 8 × 120 M1 ÷ 8 ÷ 1024 ÷ 1024 M1 3.66 A1
3
Question 4Structured · 4 marks
(a)
Convert the denary number 94 into 8-bit binary.
[1]
(b)
Convert the binary number 01110101 into hexadecimal.
[1]
(c)
Convert the hexadecimal number FA into denary.
[1]
(d)
Give the 8-bit two’s complement representation of −36.
[1]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
01011110
01011110 B1
1
(b)
75
75 B1
1
(c)
250
250 B1
1
(d)
11011100
11011100 B1
1
Question 5Structured · 2 marks
(a)
The binary number 00100111 has a logical shift 2 places to the left. Give the result.
[1]
(b)
State the effect of this shift on the denary value.
[1]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
10011100
10011100 B1
1
(b)
multiplied by 4
× 4 B1
1
Question 6Structured · 3 marks
(a)
State what is meant by the term compiler.
[2]
(b)
State what is meant by the term interpreter.
[1]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
A translator that converts a whole high-level program into machine code before it runs
A translator that converts a whole high-level program into machine code before it runs B2
2
(b)
A translator that translates and executes a program one line at a time
A translator that translates and executes a program one line at a time B1
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Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in