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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 514 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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3 questions · 6 marks

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1Describe2 marksUser Management Swap Remove

An operating system manages the users of a computer.

Describe how an operating system checks that a user is allowed to log in.

[2 marks]
Mark scheme

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

  • The user enters a username/user ID and password/PIN (1) which is compared with the account details the operating system has stored (1)
  • The operating system keeps a file/list/database of users and their passwords (1) to check the login details the user enters against (1)
  • The operating system compares the entered details with the details stored for that user (1) and if they do not match, access is refused/denied (1)
  • The entered details are checked against the access rights stored for that user (1) so access is only allowed when the details are correct (1)

Do not award for 'it asks for a password' on its own, without saying what the password is checked against.

A stored list/file of users and passwords with no check of the login details earns one mark only.

Do not accept responses about file management, such as finding or opening the user's files.

Example answers and how they were marked
Full marks2/2

The user types in a username and password. The operating system compares these with the details it has stored for that account, and if they match the user is allowed to log in.

Why: Username and password entered (1) which is compared with the account details the operating system has stored (1).

Some marks1/2

The operating system has a list of all the users and their passwords.

Why: The stored list of users and passwords (1), but no check of the login details against it, so the development mark is not earned (0); the mark scheme states a list alone earns one mark only.

No marks0/2

The operating system finds the user's files on the hard drive and opens the last one they saved.

Why: Describes file management, not checking a user's login details; the mark scheme says not to accept responses about file management, so there is no creditworthy point.

2Describe2 marksLow and High Level Languages Swap Remove

A programmer has written a program in assembly language.

Describe why it is necessary to translate the program into machine code before it can be run.

[2 marks]
Mark scheme

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

  • The processor/CPU can only execute machine code/binary instructions (1) so the assembly instructions must be converted into machine code before the program can run (1)
  • Each assembly instruction/mnemonic matches/corresponds to one machine code instruction (1) so each line must be replaced with the machine code the processor executes (1)
  • The program is written using mnemonics (1) that must be translated into machine code for the processor to carry out the instructions (1)
  • The hardware/processor does not understand assembly language directly (1) so it must be translated into machine code that the processor can execute (1)

Do not accept 'assembly language is a low-level language'.

Do not accept 'it is hard to understand' or 'it is not English'.

Do not accept benefits, such as 'machine code runs faster' or 'the program will run more quickly'.

Do not accept 'an assembler/a translator converts it' on its own, with no reference to the processor only being able to execute machine code/binary.

Do not accept responses about high-level languages or about compilers/interpreters.

Example answers and how they were marked
Full marks2/2

The processor can only execute machine code, so the assembly instructions must be converted into machine code before the program can run.

Why: States what the processor can execute (1) and links it to converting the program's instructions into machine code (1).

Some marks1/2

Each assembly instruction matches one machine code instruction.

Why: Correct point about the one-to-one match (1) but no development saying that this is because the processor only executes machine code.

No marks0/2

Because an assembler translates assembly language into machine code.

Why: Names the translator but gives no reason tied to the processor only being able to execute machine code, so no mark; this is in the 'Do not accept' guidance.

3Convert2 marksDenary to Binary Conversion Swap Remove

Binary patterns can represent numbers.

Convert the denary number 199 to 8-bit binary.

[2 marks]
Mark scheme

Award one mark for each correct nibble in the correct order:

  • 1100 (1)
  • 0111 (1)

0 marks if the response is not 8-bit binary.

Example answers and how they were marked
Full marks2/2

1100 0111

Why: 199 = 128 + 64 + 4 + 2 + 1: both nibbles are correct (2).

Some marks1/2

1100 1000

Why: Converts 200 instead (a slip in adding up the place values). The first nibble is correct (1); the second is not.

No marks0/2

1110 0011

Why: The bits are written in reverse, smallest place value first. Neither nibble is correct.

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