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Daily Practice · GCSE Computer Science

September 2021 - GCSE Computer Science 5-a-day

Every GCSE Computer Science sheet published in September 2021, with answers. Systems, data representation, networks, algorithms and programming.

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September 2021

30 sheets · 150 questions · GCSE

September 2021 compilationAll answers

Every sheet in September 2021

The same date always regenerates the same five questions, so a sheet you print today is the sheet a classmate prints tomorrow.

  1. 1st September 2021A CPU's cache has a hit rate of 80%. During a task the CPU makes 4000 requests for data. Calculate the number of cache hits and cache misses.
  2. 2nd September 2021Describe two negative consequences of throwing away old computer hardware instead of recycling it.
  3. 3rd September 2021Write a function called isEven that takes one integer parameter, num, and returns True if num is even and False otherwise.
  4. 4th September 2021State the pseudocode operator commonly used to join (concatenate) two strings, then show how it joins 'Rev' and 'ision' to produce 'Revision'.
  5. 5th September 2021A company backs up its files onto magnetic tape cartridges, each with a capacity of 3 TB. The company needs to back up 20 TB of data. Calculate the minimum number of cartridges needed.
  6. 6th September 2021A user reads the same email on a phone and a tablet, and deleting it on one deletes it on the other. Which protocol is in use and why?
  7. 7th September 2021Explain why iterative testing, carried out throughout development, tends to make errors cheaper to fix than relying only on final testing.
  8. 8th September 2021Define the term 'primary key' as used in a database table.
  9. 9th September 2021Define the term 'interrupt' as used to describe a signal received by a CPU.
  10. 10th September 2021An array called items contains [12, 45, 7, 30, 19] at indices 0 to 4. Describe how a linear search would locate the value 30, stating the number of comparisons needed.
  11. 11th September 2021Evaluate X = NOT A AND B when A = 0 and B = 1.
  12. 12th September 2021Convert the 8-bit binary number 10110100 directly to hexadecimal by splitting it into nibbles.
  13. 13th September 2021Give one advantage of a star topology compared with a mesh topology.
  14. 14th September 2021Name the translator used for assembly language and describe how it differs from a compiler.
  15. 15th September 2021Add the 8-bit binary numbers 00101101 and 00010011, giving your answer as an 8-bit binary number.
  16. 16th September 2021State the three stages of the fetch-decode-execute cycle in the order they occur.
  17. 17th September 2021State one weakness of a simple shift cipher compared to modern encryption methods used on networks.
  18. 18th September 2021Explain what happens if a program tries to read index 5 of an array declared with 5 elements.
  19. 19th September 2021Define the term 'pixel'.
  20. 20th September 2021Order these from fastest access speed to slowest: RAM, cache, registers, secondary storage.
  21. 21st September 2021Which piece of UK legislation makes it a criminal offence to gain unauthorised access to a computer system?
  22. 22nd September 2021Evaluate the expression 23 DIV 4.
  23. 23rd September 2021A function is defined as: FUNCTION addTax(price) RETURN price x 1.2 ENDFUNCTION. Another line of code runs: total <- addTax(20) + addTax(30). Trace both function calls and state the final value of total.
  24. 24th September 2021A 1 TB hard disk drive costs 40 pounds. A 500 GB solid-state drive costs 60 pounds. Calculate the cost per gigabyte of each device, and state which is cheaper per GB. Use 1 TB = 1000 GB.
  25. 25th September 2021Define the term protocol.
  26. 26th September 2021A 'quantity' field on a website must only accept whole numbers from 1 to 10. Which validation check identifies that 15 has been entered?
  27. 27th September 2021A table called staff has fields staffId, name, department and salary, storing these records: staffId | name | department | salary, 1 | Ben | Sales | 24000, 2 | Chloe | IT | 31000, 3 | Dan | Sales | 27000. State which staffId(s) would be returned by: SELECT staffId FROM staff WHERE department = 'Sales' AND salary > 25000;
  28. 28th September 2021A row of 8 pixels is WWWBBBWW. Use run-length encoding to encode this row as pairs of (colour, run length).
  29. 29th September 2021An array contains [9, 2, 6], to be sorted using insertion sort. Show the state of the array after each new element has been inserted into its correct position.
  30. 30th September 2021Complete: NOT 0 = ?