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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 604 exam-style questions, each with its mark scheme and example answers. Print it, or answer it on paper and then open the mark schemes. Or browse the questions by topic.

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4 questions · 11 marks

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1Multiple choice1 markCharacter Sets Swap Remove

A new character set must be able to represent 70 different characters.

Identify the minimum number of bits needed to represent each character.

[1 mark]
  • A6
  • B7
  • C8
  • D70
Mark scheme
  • B 7 (1)
  • The only correct answer is B. The correct answer is 7.
  • A is not correct because 6 bits give only 64 combinations, which is not enough for 70 characters
  • C is not correct because 7 bits already give 128 combinations, so 8 bits is not the minimum needed
  • D is not correct because 70 is the number of characters needed, not a number of bits
Example answers and how they were marked
Full marks1/1

B 7

Why: The only correct answer: 7 bits give 128 combinations, enough for 70 characters, and it is the smallest number of bits that does (1).

No marks0/1

C 8

Why: Distractor, no credit: a single-tick item has no partial credit, and 8 bits is not the minimum because 7 bits already give 128 combinations, so the scheme's C line gives no mark.

No marks0/1

A 6

Why: Misconception, no credit: 6 bits give only 64 combinations, which cannot represent 70 different characters, so the scheme's A line gives no mark.

2Describe2 marksMemory Management Swap Remove

A program is stored on secondary storage before it is run.

Describe how the operating system manages memory when a program is started.

[2 marks]
Mark scheme

Award up to two marks for a linked description such as:

  • The program (and its data) is copied/loaded from secondary storage into main memory/RAM (1) so that the CPU can fetch/execute its instructions (1)
  • An area of main memory is allocated/reserved for the program (1) that is large enough to hold the program and its data (1)
  • The operating system checks that there is enough free main memory (1) before the program can be started/loaded, otherwise it cannot run/an error is reported (1)
  • The operating system keeps a record of the memory addresses used by the program (1) so that its instructions and data can be found when it runs (1)

Allow 'loaded into RAM', 'stored in memory' and 'put into main memory' as equivalent to copied into main memory.

A single statement that the program is loaded/stored in main memory, with no linked development, can be given one mark only.

Do not accept descriptions of the CPU fetching/executing instructions that do not refer to the operating system loading or allocating memory.

Do not accept responses about virtual memory (moving processes to secondary storage) or about which process runs next on the CPU.

Do not accept the program being run from secondary storage/hard disk.

Example answers and how they were marked
Full marks2/2

The operating system copies the program and its data from secondary storage into main memory so that the CPU can fetch and execute its instructions.

Why: Copying the program and data into main memory (1) linked to the CPU fetching/executing instructions (1).

Some marks1/2

The operating system loads the program into main memory.

Why: The program is copied/loaded into main memory (1), but there is no linked development of how or what this leads to, so only one mark is given.

No marks0/2

The CPU fetches the program's instructions from main memory and executes them one at a time.

Why: This describes the fetch-decode-execute cycle, not the operating system loading or allocating memory, which is the Do not accept line; no creditworthy point is made.

3Explain2 marksProtocols & Layers Swap Remove

A bank's website can use HTTP or HTTPS.

Explain one benefit to a customer of the bank's website using HTTPS.

[2 marks]
Mark scheme

Award up to two marks for a linked explanation such as:

  • Data is encrypted/scrambled (1) so it cannot be read/understood if it is intercepted (1)
  • The customer's bank/personal details are kept secure/private (1) because the data is encrypted/scrambled during transmission (1)
  • The customer's login details/password cannot be read by an eavesdropper (1) because HTTPS encrypts/scrambles the data sent to and from the web server (1)

For both marks, the expansion must follow/associate with the statement.

Allow 'scrambled' as an alternative to 'encrypted'.

Do not accept 'it is more secure/safe' or 'the data is secure' on its own, without saying how it is made secure (e.g. encryption/scrambling).

Do not accept faster loading/speed, or claims that HTTPS stops viruses or always proves the website is genuine.

Example answers and how they were marked
Full marks2/2

The data is encrypted (1) so anyone intercepting it cannot read the customer's bank details (1).

Why: Linked point (1) and reason (1): encryption means intercepted data cannot be read.

Some marks1/2

The data is encrypted (1) so the website is secure.

Why: Point (1) for encryption, but 'secure' on its own is a near-miss that the mark scheme does not credit as the linked reason; it must say why, e.g. that intercepted data cannot be read.

No marks0/2

HTTPS is faster than HTTP (0) so the customer can log in more quickly.

Why: Speed is not a benefit of HTTPS and is named in a 'Do not accept' line, so no creditworthy point is given.

4Discuss6 marksLow and High Level Languages Swap Remove

A software company is writing a new program that will be sold to users who have different types of computer. The program does not need to control the hardware of the computer directly. The company must decide whether to write the program in a high-level language or a low-level language.

Discuss whether the company should use a high-level language or a low-level language to write this program.

Your answer should consider:

  • machine independence
  • processor specificity
  • how the code is translated for each type of computer.
[6 marks]
Mark scheme

Indicative content

Machine independence

  • A high-level language is machine independent, so the same source code can be run on different types of computer with few or no changes.
  • The company can write the program once and sell it to users with different computers, without rewriting the code for each type of computer.
  • Only one version of the program needs to be written and maintained, so development takes the company less time.

Processor specificity

  • A low-level language is processor-specific, so a program written for one processor will not run on a different processor without being rewritten.
  • Assembly language instructions depend on the instruction set of the particular processor, so the company would need a separate version of the program for each type of computer.
  • Writing a separate low-level version for every type of computer would take the company much longer than writing one high-level program.
  • Low-level code gives direct control of the hardware of one processor, so it is better suited to device drivers than to a program that must run on many different computers.

Translation

  • High-level source code is translated for each type of computer by a compiler or an interpreter, so one version of the source code is enough for all the users.
  • Assembly language is translated into machine code by an assembler, and the assembler produces machine code for one specific processor only.
  • Machine code is already in a form that one particular processor can execute directly, but the same machine code will not run on a different processor.
  • Each high-level statement translates into several machine code instructions, so the programmer does not need to know the instruction set of the processor.

Levels

  • Level 0 (0 marks): No rewardable content.
  • Level 1 (1–2 marks): Basic, independent points are made, showing elements of understanding of key concepts/principles of computer science. (AO1) The discussion will contain basic information with little linkage between points made or application to the context. (AO2)
  • Level 2 (3–4 marks): Demonstrates adequate understanding of key concepts/principles of computer science. (AO1) The discussion shows some linkages and lines of reasoning with some structure and application to the context. (AO2)
  • Level 3 (5–6 marks): Demonstrates comprehensive understanding of key concepts/principles of computer science to support the discussion being presented. (AO1) The discussion is well developed, with sustained lines of reasoning that are coherent and logically structured, and which clearly apply to the context. (AO2)

Additional guidance

  • Level 3 responses must cover both high-level machine independence and low-level processor specificity, with the effect on the company's decision.
  • Do not award low-level language, assembly language or machine code as portable, or 'high-level languages are written in English/like English' as a reason for machine independence.
Example answers and how they were marked
Full marks6/6

A high-level language is machine independent, so the company can write the program once and it will run on different types of computer with few or no changes. A different compiler is used for each type of processor to translate that same source code into the machine code for that computer, so the company can sell one program to all of its users. A low-level language is processor-specific, so a program written in assembly for one processor will not run on a different one. The assembler produces machine code for one particular instruction set, so the company would need to write a separate version for each type of computer, which would take much longer. As the program does not need to control the hardware directly, the company should use a high-level language.

Why: Develops high-level machine independence with the compiler translating for each processor, and low-level processor specificity with the assembler producing machine code for one instruction set, both applied to the company's decision, in a coherent and sustained argument: Level 3, 6 marks.

Some marks3/6

A high-level language is machine independent, so the company can write the program once. A different compiler is used for each type of computer to translate the code, so users with different computers can all run the same program. A low-level language is processor-specific, so it would not be as suitable for the company.

Why: Machine independence is linked to the compiler and applied to the users, but processor specificity is only asserted and no translation of low-level code is given, so the reasoning is not sustained: Level 2, 3 marks.

Some marks1/6

High-level languages are machine independent because they are written in English, so the company can sell the program to anyone. Low-level languages are machine code, so they can be translated to run on any type of computer.

Why: One basic point that high-level languages are machine independent, applied by selling to anyone (1). 'Written in English' is not a reason for machine independence and low-level code is not portable, so neither is credited: Level 1, 1 mark.

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