ACSBR 2019 P1 Solution

Prelim Examination 2019 1 Secondary 4 Express Computing 7155/01 PRELIMINARY EXAMINATION 2019 SECONDARY FOUR EXPRESS COMPUTING PAPER 1 7155/01 Marking Scheme Anglo-Chinese S chool (Barker Road)

Anglo-Chinese School (Barker Road) Prelim Examination 2019 2 Secondary 4 Express Computing 7155/01 1 (a) Convert 32 KB into bytes. …………………………………………………………………………………….. [1] (b) Convert 3 MiB into bytes. …………………………………………………………………………………….. [1] 2 Draw a line to match the role to its correct description. Roles arithmetic logic unit • address bus • data bus • control unit • memory • output • Description • Stores data, instructions and the result of processing for immediate use memory • Transports required memory location from processor to memory; uni-directional address bus • Intermediate or final results produced by the computer; usually in the form of processed data output • Part of the processor that processes data by performing basic mathematical and logical operations arithmetic logic unit [4] 3 Insert four of the following phrases in the correct space below. Metropolitan Area Network Internet protocol Router Wide Area Network Service Set Identifiers Network Interface Card (a) ……………………………………………...…. provides the hardware interface to enable the transfer of data between a device and a network. (b) ……………………………………………...….. is a 32-byte string that indicates a wireless access point (WAP) and all devices connected to it. (c) …………………………………………...…….. allows separate networks that use different network protocols to be connected together (d) ……………………………………………...…..: Network of computing devices typically spanning across two or more buildings within the same town or city. [4] 32×10!=32000 3 ×10242 =3 145 728 Network interface card Service Set Identifiers Router Metropolitan Area Network

Prelim Examination 2019 3 Secondary 4 Express Computing 7155/01 4 Your company is setting up a new office and you as the manager of the new office need to decide to install wireless or wired nework. Give one advantage and one disadvantage of a wireless network as compared to a wired network. Advantage……………………………………………………………………..……………… ...........…………………………………………………………………………..……………... ...........…………………………………………………………………………..……………... Disavantage……………………………………………………………………..……………. ...........…………………………………………………………………………..……………... ...........……………………………………………………………………………........... [4] Advantage • For wireless network, mobility of users is higher as users can move about freely within the range of the wireless network. For wired networks, mobility of users is lower as network connections are fixed at specific spots and users cannot move to other locations. • For wireless network, adding new devices to the network is easier as the router can be easily configured. For wired networks, it is more cumbersome to add new devices to the network as physical constraints and the running of cables need to be considered. • Wireless networks are more organised without cables. Wired networks tend to look more disorganised due to cables running across floors. Disadvantage • For wireless networks, cost is higher as wireless networking equipment is more expensive. For wired networks, cost is lower as equipment and cables are cheaper. • For wireless networks, transfer rate is generally slower and has lower bandwidth due to possible interference from radio waves or microwaves; varies according to user location in relation to network. For wired network, transfer rate is faster and has higher bandwidth as cables provide dedicated connection. • Wireless networks are less reliable due to potential interference from radio waves and microwaves or blockage from physical obstructions. Wired networks are more reliable as data transmission is unaffected by interference. • Wireless networks are less secure due to possible intrusion by hackers. Wired networks are more secure as the network is less susceptible to interception and hacking.

Prelim Examination 2019 4 Secondary 4 Express Computing 7155/01 5 The use of technology has impact our lives in many areas. Describe two advantages and two disadvantages of the impact of technology on healthcare. Advantage 1 ……………………………………………………………………..………….... ...........…………………………………………………………………………..…………...… ...........…………………………………………………………………………..…………...… Advantage 2 ……………………………………………………………………..………….... ...........…………………………………………………………………………..…………...… ...........…………………………………………………………………………..…………...… Disavantage 1 ……………………………………………………………………..…………. ...........…………………………………………………………………………..…………...… . ..........…………………………………………………………………………..…………...… Disavantage 2 ……………………………………………………………………..…………. ...........…………………………………………………………………………..…………...… ...........…………………………………………………………………………..……….. [4] Advantages • Video conferencing gives patients who are located in remote places or have limited mobility better access to healthcare. • Allow patients to securely transfer potentially sensitive medical information. • Use of robots to dispense medicine and other more menial tasks. • The rise of 3D-printing technology has also opened up new opportunities in the building and customisation of prosthetic limbs, hearing aids and dental fixtures. Disadvantage • Some patients find the use of robots and other technology in healthcare impersonal and mistrust the ability of machines to provide proper healthcare. • Other patients may misuse information from the Internet and make potentially dangerous decisions based on incorrect diagnoses

Prelim Examination 2019 5 Secondary 4 Express Computing 7155/01 6 It is an increasing trend in online transactions such as i-banking and e-shopping. This has led to an increase in pharming. (a) Describe what pharming is and how it works. ...…………………………………………………………………………..…………...... ...……………….…………………………………………………………..…………..... ....…………………………………………………………………………..……… [2] (b) One way to avoid being pharmed is to ensure that public key encryption is used when submitting credit card or other sensitive information via the Internet. Explain how public key encryption works. ...……………….…………………………………………………………..…………..... ...……………….…………………………………………………………..…………..... ...…………………………………………………………………………..………. [2] (c) Suggest another way to avoid being pharmed. ...…………………………………………………………………………..…………...... ...……………….…………………………………………………………..…………..... ...…………………………………………………………………………..………. [2] 7 Name two types of external storage that are commonly found in a computer system, list their corresponding example and describe each of them in terms of their advantage and disadvantage. Type 1…………………………………………………………………………..…………...… Example …………………………………………………………………………..…………... Description……………………………………………………………………..…………...… ...........…………………………………………………………………………..…………...… Type 2………………………………………………………………………..…………...…… Example …………………………………………………………………………..…………... Description……………………………………………………………………..…………...… ...........…………………………………………………………………………..………. [6] •The interception of requests sent from a computer to a legitimate website and redirection to a fake website •to steal personal data or credit card details •Encoded messages that can only be read by the intended recipient with a private key. •Look for the “https://” and a padlock icon appears next to its address on a web browser. Any one from the following: •Regularly check bank, debit/credit card and other statements •Regularly update web browsers and software •Make sure that two-factor authentication is enabled for all bank transactions. Type: Magnetic Example: hard disk Description: They have large storage capacity (Terabytes). However, they are vulnerable to drops and mechanical shocks. Type: Optical Example: Digital Versatile Disc (DVD) Description: They have large storage capacity (Gigabytes). However, they are vulnerable to scratches and fingerprints. Type: Solid Stat