Edexcel GCSE Computer Science (1CP2) Exam Questions

• C No data is lost and the original file can be recreated (1)
• The only correct answer is C. The correct answer is no data is lost and the original file can be recreated.
• A is not correct because encryption hides data and does not make the file smaller
• B is not correct because permanently removing data is lossy compression
• D is not correct because splitting a file into packets is part of transmission, not compression

• B The destination IP address (1)
• The only correct answer is B. The correct answer is the destination IP address.
• A is not correct because a domain name is converted to an IP address by a DNS server before routing begins
• C is not correct because the sender's MAC address is only used to deliver the packet on the local network
• D is not correct because the file name is not used to route packets

Award one mark for:

• Router (1)

Allow routers (plural).

Allow minor spelling errors that are clearly router, e.g. rooter.

Do not accept switch, hub (these forward data within a network, not between networks), modem or server.

Do not accept gateway on its own.

Award one mark for:

• 224 (1)

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Do not accept 'it is old/out of date' or 'it cannot store numbers'.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 one mark for each of:

• 5 × 1024^3 / 5 × 1024 × 1024 × 1024 / 5 × 2^30, for the number of bytes (1)
• A fully correct expression with × 8 to convert bytes to bits, in any order, e.g. 5 × 1024^3 × 8, 8 × 5 × 2^30 (1)

Accept 5 × 1 073 741 824 × 8.

Accept 5 × 2^33 or 42 949 672 960 as a fully correct expression (2 marks).

Do not accept 5 × 1000^3 × 8, which uses decimal multiples.

Do not accept ÷ 8, which converts bits to bytes.

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.

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

• Instructions can manipulate/control the hardware/memory/registers directly (1) so the driver can control the specific device it is written for (1)
• The code is written for one specific processor/architecture (1) so it works with the exact hardware it will control (1)
• The programmer controls exactly how memory/registers are used (1) so the code is efficient and needs little memory, which suits a device that has limited memory (1)
• Each instruction maps to one machine code instruction (1) so the driver code is small enough to fit in the memory of the device (1)

Extra detail, such as naming the device the driver controls, is not needed to earn the marks.

Do not accept 'it is closer to machine code' on its own: it must be developed to show how this helps the driver, e.g. it can control the hardware directly.

Do not accept 'it is faster/quicker' with no link to the hardware/device, e.g. the device responds quickly.

Do not accept 'it is easier to learn', 'it is easier to debug' or 'it takes less time to write'.

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.