Edexcel GCSE Computer Science (1CP2) Exam Questions

Award one mark for any of the following up to a maximum of two marks:

• (Only) 128 different characters can be represented / 7 bits give 2^7 = 128 different codes (1)
• It cannot represent characters from languages other than English / non-English alphabets, e.g. Greek, Chinese (1)
• It cannot represent accented characters, e.g. é, ñ (1)
• It cannot represent symbols or emoji that are not in the ASCII character set (1)

Award a maximum of one mark for the last three bullets, as they are all examples of characters that fall outside the 128 ASCII codes.

Allow 'it can only represent 128 characters, so some characters are missing' for the first bullet.

Do not accept 'it uses 7 bits' / 'it only uses 7 bits' on its own, without saying what this limits.

Do not accept 'it can only store a limited amount of text' / 'it can only store short messages', as 7 bits limits the number of characters available, not the length of a message.

Do not accept 'it can only represent the characters in the ASCII character set', as this repeats the question.

Do not accept 'it is old/out of date' or 'it cannot store numbers'.

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

• A storage limit/quota is set for each user account (1) so the drive is shared fairly between users (1)
• The operating system records how much space each user's files are using (1) and refuses to save more files when the limit is reached (1)
• Each user is given a fixed share/quota of the drive (1) so one user cannot use the space set aside for another (1)

Allow a limit set by an administrator or through the operating system's user management settings; an administrator is not required for credit.

Allow a warning that stops the save; do not award the development for a warning alone where the save is not stopped.

Do not accept responses about passwords/authentication, keeping files separate/folders with no storage limit, deleting old files, compressing files, or buying a larger drive.

Do not accept 'the operating system gives the user a bigger hard drive'.

Do not accept a single global limit for all users; the limit must apply to each user/user account.

Indicative content

Why secondary storage is needed

• Secondary storage is non-volatile, so it keeps the operating system, applications and students' work when the power is turned off.
• It stores programs and files that are not currently in use, so they are not lost when the computer is switched off.
• It provides a larger capacity than primary storage for files such as students' work, videos and photographs.
• It allows each computer to keep many students' files and the software the school has installed.

The difference between primary and secondary storage

• Primary storage (RAM) is volatile and directly accessible by the CPU; secondary storage is non-volatile and not directly accessible by the CPU.
• RAM holds the data and instructions currently in use; secondary storage holds data and programs long term.
• Primary storage is faster but smaller and more expensive per gigabyte; secondary storage is slower but larger and cheaper.
• The school's computers need both: RAM to run the operating system and applications, and secondary storage to keep them when the computer is switched off.

A suitable type of secondary storage for the school's computers and a reason why it is suitable

• A solid state drive (SSD) is suitable because it has no moving parts, so it is durable and quiet, and has fast read/write speeds, which helps the computers start up quickly.
• A magnetic hard disk drive (HDD) is suitable because it is cheap and offers a very large capacity, which is useful for storing many students' files.
• Either type could be used; a small SSD for the operating system and applications plus a large HDD for files would balance speed and cost.

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

• Award credit for a type of secondary storage only when a reason is given that is linked to the school's computers; a named type alone (e.g. 'SSD') is not creditworthy. Do not accept RAM as secondary storage or the claim that secondary storage is the same as RAM. Do not accept CD/DVD/Blu-ray as the main storage for the school's computers because their capacity is too low and write speeds are slow.
• For Level 3, the answer must cover all three bullets and apply at least one point to the school's computers. A 6-mark answer is well developed with sustained reasoning and a justified choice; a 5-mark answer covers all three but with limited development or application. Comparisons of speed and cost between primary and secondary storage are creditworthy as part of the difference.