9618/11 May/June 2023

Define each image term:

• Pixel:

• Colour depth:

• Pixel: Smallest part of the image

• Colour depth: Number of bits per pixel

Identify two other items that could be in a bitmap file header.

1. File type

2. Compression type

Why might RLE not reduce the file size of a bitmap?

• RLE stores colour and count of repeats

• If image has no long sequences of same colour, count is often 1

• Adds more data instead of reducing size
  Example: Red 1, Green 1, Blue 1

Define data integrity and give one implementation method.

• Definition: Ensures data is consistent and accurate

• Example: Enforcing Referential integrity / cascading update or delete / validation rules

Match each normal form to its definition:

• 1NF:

• 2NF:

• 3NF:

• 1NF: No repeating groups

• 2NF: All fields fully dependent on entire primary key

• 3NF: No partial dependencies

How does the OS manage peripheral hardware?

• Installs device drivers

• Sends/receives data from peripherals

• Manages data flow using buffers

• Handles device interrupts

• Allows communication between CPU and input/output device

Identify two other key management tasks of the OS.

• Memory management

• File management

• Security management

• Process management

• Error handling

How does defragmentation improve computer performance (RRF)

• Rearranges blocks of files to be contiguous

• Reduces read time by limiting disk head movement

• Faster access to files / reduced seek time

Difference between kibibyte and kilobyte.

• Kibibyte = 1024 bytes

• Kilobyte = 1000 bytes

Describe the contents of the ROM in the central computer.

• Stores the bootstrap/start-up instructions for the system

• May include firmware for CCTV

• May include parts of the operating system (e.g. kernel)

Give two advantages of using DRAM instead of SRAM.

• DRAM is cheaper per unit

• DRAM has higher storage density
  (Also valid: DRAM has simpler design / fewer transistors)

Give two reasons why magnetic storage is more appropriate than solid-state storage for CCTV

1. Magnetic storage is more durable for frequent read/write operations

   • CCTV system runs continuously

2. Magnetic storage is cheaper per storage unit

   • Video files are large, so high capacity is needed

How is AI used in a CCTV system to identify and track a person?

• Uses image recognition to detect human features

• Matches patterns/shapes to a person

• Starts recording when a person is identified

• Identifies movement direction

• Activates other cameras based on movement

Complete the description of IPv4 and IPv6 addresses.

• IPv4:

• IPv6:

• IPv4: 4 groups, 8 bits each, separated by full stops

• IPv6: 8 groups, 16 bits each, groups of zeros can be shortened using double colon or ::

Describe two benefits of subnetting a network.

• Reduces network traffic

  • Data stays within subnet, doesn’t travel far

• Improves security

  • Devices can be restricted from accessing all parts of the network
    (Other valid: Easier maintenance – can isolate one subnet while others stay active)

:Describe the functions of the following logic gates:

• NAND:

• NOR:

• NAND: Outputs 0 only if both inputs are 1

• NOR: Outputs 1 only if both inputs are 0

Explain how a computer handles a keyboard interrupt.

• Interrupt flag is raised in interrupt register

• At the end of current F-E cycle, system checks priority

• If higher priority, contents of registers are saved to stack

• ISR (Interrupt Service Routine) for keyboard is called

• Keyboard input is processed

• Register contents restored from stack

• Control returns to previously running process