SST 2020 Computing P1 Solution

1 2020 SEC 4 COMPUTING PRELIM EXAM MARKING SCHEME Qn 1 Marking Scheme / Answer Marks (a) Roles arithmetic logic unit • address bus • control unit • data bus • process register • RAM • ROM • Description • Data storage space that is extremely fast but small. It is physically located inside the processor and cannot be changed without changing the processor. • Transports required memory location from processor to memory; uni-directional • Where data and instructions are stored temporarily so that they can be quickly accessed by the processor when needed. • Part of the processor that follows instructions and decides when data should be stored, received or transmitted by different parts of the computer. Qn 2 Marking Scheme / Answer (a) American Standard Code for Information Interchange (b) 716 = 1112 C16 = 11002 (7C)16 = 11111002 (c) 10111002 = 26 + 24 + 23 + 22 = 64 + 16 + 8 + 4 = 9210 (d) 109 / 16 = 6 R 13 13 / 16 = 0 R 13 (109)10 = 6D16 (e) IPv4 uses 4 bytes IPv6 uses 16 bytes Qn 3 Marking Scheme / Answer (a) - Positive: Technology has provided better videos, simulations and collaboration tools for lessons to be more engaging and relevant. - Positive: Open sharing of information has made education accessible to all, even learners from disadvantaged backgrounds. - Negative: Students’ attention spans are getter shorter as they are more distracted by technology and social media.

2 - Negative: Students are more prone to gaming and internet addiction. - Negative: Students are more prone to cyberbullying (b) Similarity: Both are computer programs that copy themselves and sends copies of themselves to other programs or computers. Difference: A worm does not need to attach itself to an existing program while a virus does. Qn 4 Marking Scheme / Answer (a) Access Control / Authorisation Authentication Understanding of Private Policies Biometrics ✓ Cloud Services ✓ Encryption ✓ Firewalls ✓ Passwords ✓ Social Networking sites ✓ (b) 2FA stands for two-factor authentication. It is a form of authentication that uses evidence from something the user knows And something the user owns. Qn 5 Marking Scheme / Answer Inputs: - Name of Runner, - Gender of Runner (Girl or Boy) - Timing of Runner Processes: - For each gender compare the timing of students and find the name of student with minimum timing, and the respective timing itself. - Store all data in array/list - Sort data into each gender Qn 6 Marking Scheme / Answer (a) - Shared resources: a network allows a group of computers to make use of shared resources such as printers or files. - Shared internet access: depending on the network’s configuration, every user who logs on to the network may have access to the internet. - Shared software: Software can be stored on the central server of a network and deployed to other computers over a network. - Shared storage: Data files can be stored on a central server for ease of access