ICT: Computer Systems — Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs — examination boards hold copyright in their own papers. Use these alongside the official past papers available free from your board.

Related: Computer Systems revision notes

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Section A

1. State the role of each of the following: the processor, main memory, read-only memory, and backing storage. [4]

2. Distinguish between an input device, an output device and a storage device, giving an example of each. [3]

Section B

3. Explain the difference between primary and secondary storage, and explain why a computer needs both. [5]

4. A business is choosing between magnetic, optical and solid state storage for backing up 5 TB of data weekly.

(a) Recommend a medium and justify it with two reasons. [4] (b) Explain why backups should also be stored off-site. [2]

5. Explain four threats to data security and describe one measure to counter each. [12]

6. Explain the difference between a wired and a wireless network, giving one advantage of each, and explain the role of a router. [6]

Section C

7. Distinguish between a health risk and a safety risk of using computers, giving one example of each with its prevention. [4]

8. Explain two examples of microprocessor-controlled devices used in the home, and one advantage and one disadvantage of each. [8]

9. Explain two examples of microprocessor-controlled devices used in transport, and one advantage and one disadvantage of each. [8]

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Answers

1. The processor — fetches, decodes and executes instructions, performing the calculations and logical comparisons a program requires [1]. Main memory (RAM) — holds the programs and data currently in use, so the processor can access them quickly; volatile [1]. Read-only memory (ROM) — holds the boot instructions needed to start the computer; non-volatile and normally unwritable [1]. Backing storage — holds programs and files permanently, even with the power off, for use when needed [1].

2. Input — sends data into the system, e.g. a keyboard or scanner [1]. Output — presents processed data to the user, e.g. a monitor or printer [1]. Storage — retains data for later use, e.g. a hard disk [1].

3. Primary storage is directly accessible by the processor and holds what is in use now; it is fast but small and mostly volatile [1] [1]. Secondary storage is not directly accessible by the CPU and holds programs and files permanently; it is much larger and non-volatile but far slower [1] [1]. Both are needed because RAM is too small and too expensive to hold everything and loses its contents when the power goes off, while secondary storage is far too slow for the processor to work from directly [1].

4. (a) Magnetic hard disks or tape [1]. They offer the lowest cost per terabyte, which matters at 5 TB per week [1]; capacity is ample and write speeds are adequate for an overnight backup, and tape in particular has a long archival life [1]; optical discs would require an impractical number of discs and SSDs would be far more expensive per terabyte [1]. (b) If the backup is stored in the same building, a fire, flood or theft would destroy the original data and the backup together [1], so an off-site or cloud copy is essential for recovery from a site-wide disaster [1].

5. Any four, 3 marks each: Malware (viruses, ransomware) — programs that damage data or hold it to ransom [1] [1]; countered by anti-malware software kept up to date, and regular offline backups so encrypted data can be restored [1]. Phishing — fraudulent emails or sites that trick users into revealing credentials [1] [1]; countered by staff training to recognise suspicious messages and by two-factor authentication, so a stolen password alone is insufficient [1]. Hacking / unauthorised access — an outsider gains entry to the network [1] [1]; countered by a firewall, strong password policy and access rights limiting each user to what they need [1]. Data interception — data read while being transmitted [1] [1]; countered by encryption, so intercepted data is unreadable without the key [1]. Accidental loss or hardware failure [1] [1]; countered by a regular, tested backup routine and RAID redundancy [1]. Insider misuse [1] [1]; countered by access levels, audit logs and physical security [1].

6. A wired network connects devices by cable; a wireless network connects them by radio [1]. Wired advantage: faster, more reliable and more secure, since the signal cannot be intercepted from outside the building [1]. Wireless advantage: devices can move freely and no cabling is needed, so it is cheaper to install and more flexible [1]. A router connects the local network to another network, usually the internet [1]; it examines the destination address of each data packet and forwards it along the best route [1], and typically also provides the firewall, DHCP addressing and wireless access point functions [1].

7. A health risk is a long-term physical effect of computer use [1], e.g. RSI, prevented by a wrist rest, correct posture and regular breaks [1]. A safety risk is an immediate danger [1], e.g. electrocution, prevented by not overloading sockets and keeping drinks away from equipment [1].

8. Any two, 4 marks each: washing machine — a microprocessor controls the wash cycle, water temperature and spin speed; advantage: consistent, programmable washes without constant supervision; disadvantage: a fault in the control chip can disable the whole machine [2] [2]. Central heating system — a microprocessor-controlled thermostat regulates temperature automatically to a programmed schedule; advantage: energy savings and consistent comfort without manual adjustment; disadvantage: depends on correct sensor placement and a power supply, so a sensor fault or power cut disables the automation [2] [2]. Cooker/oven — microprocessor control of cooking time and temperature; advantage: precise, repeatable results; disadvantage: less flexible than manual control if a recipe needs an unusual setting [2] [2].

9. Any two, 4 marks each: engine management system — a microprocessor controls fuel injection and ignition timing; advantage: better fuel efficiency and lower emissions than manual carburettor tuning; disadvantage: specialist equipment is needed to diagnose and repair a fault [2] [2]. anti-lock braking system (ABS) — a microprocessor monitors wheel speed and releases braking pressure to prevent a wheel locking; advantage: shorter, more controlled stopping distances on slippery surfaces; disadvantage: added cost and complexity compared with a simple mechanical braking system [2] [2]. satellite navigation system — a microprocessor calculates position and route from GPS signals; advantage: real-time route guidance and traffic updates; disadvantage: unreliable without a clear satellite signal or up-to-date map data [2] [2].

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Where marks are usually lost

• Saying RAM is a type of secondary storage.
• Recommending a storage medium without justifying it against the stated requirement.
• Naming a security threat without a matching countermeasure.
• Confusing a router with a switch.