Specimen (2024) Marking Scheme - Paper 1 CAIE Computer Science GCSE

Question 1(a) One mark per each correct four bits. 97 5C Answer Marks 4 1(b) 1(c) 1(d)(i) 1(d)(ii) 1(e) Any four from: 4 • used to identify a device • it is a unique (address) • it is a static address // it does not change • it is set by the manufacturer • the first part is the manufacturer ID / number / identifies the manufacturer • the second part is the serial number / ID. Any two from: 2 • colour codes // colour in HTML/CSS • error messages • locations in memory • memory dump // debugging • IP(v6) address • ASCII // Unicode • assembly language • URL. 1 The value becomes incorrect because the left most bits are lost. 1 One mark for method, e.g. conversion to binary then flipping and adding 1. 2 One mark for correct answer. 1 1 0 0 1 0 1 0 Question Answer Marks 2(a) Any four from: • it has a header • … that contains the destination address • … that contains the packet number • … that contains the originator’s address • it has a payload • it has a trailer. 4 2(b)(i) C 1 2(b)(ii) • lossy • lossless 2 2(b)(iii) Any four from: • parallel would allow fastest transmission • … of the large amount of data • data can be uploaded and downloaded … • … but this does not have to be at the same time • data is not required to travel a long distance • … therefore skewing is not a problem. 4 2(c)(i) Any four from: • multiple computers are used as bots • designed to deny people access to a website • a large number / numerous requests are sent (to a server) … • … all at the same time • the server is unable to respond / struggles to respond to all the requests • the server fails / times out as a result. 4 2(c)(ii) firewall OR proxy server 1