BVSS Prelim P1 MS

2024 Sec 4 Express Computing P1 Marking Scheme Qn Answers Marks 1 (a) 203 1 (b) 1 mark for each point • Divide 298 repeatedly by 16 and record the respective remainder, until the quotient is 0 • For remainder 0 – 9, the hexadecimal digit is the same. For remainder 10 – 15, the hexadecimal digit is A to F respectively. The hexadecimal number is the remainder read from bottom up • 298 = 12A Alternate solution: • Convert to binary - Divide 298 repeatedly by 2 and record the respective remainder until the quotient is 0 - The binary number is the remainder read from bottom up • From the rightmost, group 4 bits into 1 hexadecimal digit. Find the denary equivalent of each group of 4 bits. For 0 – 9, the hexadecimal digit is the same. For 10 – 15, the hexadecimal digit is A to F respectively. • 298 = 1 0010 1010 = 12A 3 (c) • Manufacturer's identity number • Device's serial number 1 1 (d) • 3116 = 0011 0001 The last 8 bits of the device in (c) is not 0111 0001. • Hence, the device is (c) is not the unauthorised device Alternative solution: • 0111 0001 = 7116 The hexadecimal is not 31. • Hence, the device in (c) is not the unauthorised device 1 1 2 MID SMALL VLOOKUP SUMIF COUNTBLANK 1 1 1 1 1

3 4 4 (a) Trojan horse [any one] • a computer program that pretends to be a harmless or useful application • once a trojan horse is run, it does something harmful such as giving intruders unauthorised access to the computer Worm • a computer program that runs automatically and attempts to spread by sending copies of itself to other computers Pharming • the interception of requests sent to a legitimate website and redirection to a fake website to steal personal data 1 1 1

(b) Positive [any one] • better videos, simulations and collaboration tools makes lessons more engaging • sharing of information on the Internet makes education accessible to all • enables improved communication between learners and teachers Negative [any one] • leads to learners' shorter attention span • heavy investment in materials and infrastructure • need to retrain and pick up new skills 1 1 (c) The crime of copying, distributing and/or using proprietary software in a manner that is not permitted by its licence 1 5 (a) Valid stores a Boolean that indicates if Value is a valid binary or not. If Value contains only '0' and/or '1', Valid is True. Otherwise, Valid is False [must be in the context of the question] 1 1 (b) (i) Main program Check() Success() Data Result Output Valid Count Value returned Total Value returned 13111 TRUE 0 FALSE FALSE 1 FALSE Error 1 mark for main program 1 mark for Check() 2

(b) (ii) Main program Check() Success() Data Result Output Valid Count Value returned Total Value returned 10011 TRUE 0 1 2