Computer Science Paper 13
Oct / Nov 2016·2210·11 questions
Mock exam: 105 min, official timing
Question paper
Question 1
Question 2
Question 3
Question 4
Question 5
Question 6
Question 7
Question 8
Question 9
Question 10
Question 11
Mark scheme
Question 1
In any order: – Fetch – Decode – Execute [3]
Question 2
– Hacking – Virus – Cookies – Cracking – Pharming [5]
Question 3
[5]
Question 4
4(a)[2]
Any two from:
– Easy to make a mistake – Can be slow if not trained – Dirt/food can get into keys [2]
4(b)[4]
Any two with identification and explanation from:
– Fewer typing errors may be made … – … because one button is pressed to order an item – Speed up the time to enter an order … – … because fewer buttons are pressed to complete the order – May require less training … – … because it is easier to identify an order item from its image rather than typing it – Can stop dirt/food damage … – … normally has a protective layer // because there are no keys for dirt/food to get into [4]
4(c)[4]
1 mark for security measure, 1 mark for description. Any two from:
– Encryption – If the data is accessed or stolen it will be meaningless – Biometric device – Can help prevents unauthorised access to the system (only award once) – Firewall – Can alert to show unauthorised access attempt on the system – Can help prevent unauthorised access to the system (only award once) – Can help protect against viruses and malware entering the system – Anti-spyware – Can stop the keys being logged that, when analysed, would reveal the password to the data [4]
Question 5
5(a)[5]
1 mark per correct section. [5]
5(b)[4]
4 marks for 8 correct values 3 marks for 6 correct values 2 marks for 4 correct values 1 mark for 2 correct values A B C Working space X 0 0 0 0 0 0 1 0 0 1 0 1 0 1 1 0 1 0 0 1 1 0 1 1 1 1 0 1 1 1 1 0 [4]
A B C X
5(c)[1]
Register Z [1]
5(d)(i)[1]
(byte) 5 [1]
5(d)(ii)[1]
(column) 4 [1]
5(d)(iii)[1]
corrected byte is: 1 0 0 1 1 1 1 1 [1]
5(d)(iv)[1]
that gives the value: 1 5 9 (follow through applies) [1]
5(d)(v)[2]
Any two from:
– The byte would be transmitted without having 5 consecutive 1’s – The fault condition would not be recognised [2]
Question 6
Any two from:
High level language – easier/faster to write code as uses English-like statements – easier to modify as uses English-like statements – easier to debug as uses English-like statements – portable language code Any two from:
Low level language – can work directly on memory locations – can be executed faster – translated program requires less memory [4]
Question 7
Any four from:
– reaches maximum brightness quickly – colours are vivid – good colour definition/contrast can be achieved – screens can be thinner/thin – more reliable as LED’s are long lasting – consume very little/less energy [4]
Question 8
[4] It is more difficult to debug the code since one error can produce many other associated errors The speed of execution of program loops is slower. It produces fast, executable code that runs directly on the processor It is easier to debug the code since an error is displayed as soon as it is found. Compiler Interpreter
Question 9
Any six from:
– infrared / motion / pressure (sensor) // sensor detects movement/pressure – signals/data sent (continuously) to microprocessor – converted from analogue to digital (using ADC) – microprocessor compares value with those stored in memory – if sensor value does not match the stored value(s) … – … signal sent to switch on the light – … signal sent to keep the light on – … light remains on for a period of time (30 seconds) – if sensor value matches the stored value(s) … – … light will remain off – … will turn off after period of time (30 seconds) – works in a continues loop [6]
Question 10
10(a)(i)[2]
2 marks for 3 correct binary conversions, 1 mark for 2 correct binary conversions [2]
0 0 0 1 1 0 1 0 1 1 1 1
10(a)(ii)[3]
1 mark for each correct hex value converted 1 A F [3]
10(b)[3]
2 marks for working + 1 mark for correct answer Working – 1200 × 8 = 9600 (bytes) – 9600/1024 or 9600/1000 – 9.4 or 9.6 kilobytes [3]
10(c)[2]
Any one from:
MAC address – Media Access Control (address) – unique number that identifies a device (connected to the Internet) – address is made up of manufacturer id + serial number of device – address is allocated by the manufacturer Any one from:
IP address – Internet Protocol (address) – location/address of a device on the Internet – address is unique for given Internet session – address is supplied when a device connects to the Internet – address is allocated by the network [2]
10(d)[2]
– record (layer) – handshake (layer) [2]
Question 11
Any six from:
– Help stop the misuse of computers – The use of computers needs to be governed – Help keep users safer when using computers – Provides rules for using computers – Help stop intellectual property theft – Helps prevent the misuse of personal information – Reference to laws (relevant example) – Reference to security issues (relevant example) NOTE: Answer must refer to the importance of ethics and be more than a description of ethics. [6]