All Definitions & Functions

Question 1

Character set

Answer 1

The set of characters that can be represented by a specific computer system

Question 2

Images

Answer 2

Pixel-picture element

Question 3

Colour depth

Answer 3

The number of possible colours a pixel might be

Question 4

Resolution

Answer 4

The number of pixels per unit area

Question 5

Meta data

Answer 5

Data about the file

Question 6

Bit depth

Answer 6

The number of bits available per sample that can be used to store the amplitude measurement

Question 7

Bitmap

Answer 7

A type of digital image where colors are stored for each pixel in a grid

Question 8

True colour

Answer 8

24 bits per pixel - used in all modern cameras etc.

Question 9

Sampling interval

Answer 9

The time between samples

Question 10

Fetch Decode Execute Cycle

Answer 10

Instructions are fetched from RAM, decoded using the CPU’s instruction and executed. The cycle then repeats

Question 11

ALU (Arithmetic Logic Unit)

Answer 11

Carries out arithmetic operations and logical operations

Question 12

CU (Control Unit)

Answer 12

Decodes and execute the instructions

Question 13

Cache

Answer 13

Very (very) fast memory with a very fast read/write speed - holds recently/frequently used instructions that have been fetched from RAM

Question 14

Register

Answer 14

A super duper small memory circuit

Question 15

ACC (Accumulator)

Answer 15

Temporary store of results from the ALU

Question 16

PC (Program Counter)

Answer 16

Increments once every FDE, stores the address of the location of the next instruction

Question 17

MAR (Memory Address Register)

Answer 17

Stores the address of the location of the current instruction/data in memory

Question 18

MDR (Memory Data Register)

Answer 18

Stores the data/instruction that has just been fetched from memory

Question 19

Clock speed

Answer 19

A measure of how many FDE cycles are completed every second

Question 20

Cache size

Answer 20

If the cache is larger, then more recently/frequently used instructions can be stored in it

Question 21

Number of cores

Answer 21

If the number of cores is increased then the system may be capable of parallel processing

Question 22

RAM (Random Access Memory)

Answer 22

Holds the machine instructions of all running programs and their data

Can be rewritten or deleted - volatile

Data will be lost if the machine is powered off

Question 23

ROM (Read-Only Memory)

Answer 23

Holds any machine instructions and data required at start-up, before the OS (operating system) is launched from the hard disk

Contents cannot be changed - non-volatile

Question 24

Virtual Memory

Answer 24

Part of the hard drive that is used as an extension to the RAM when the RAM is full (or nearly full)

More programs can run at the same time, increasing the amount of data used which slows the computer’s performance

Question 25

Secondary storage

Answer 25

The hard drive or any storage that preserves its contents when the power is turned off

Question 26

Storage type : Magnetic

Answer 26

e.g. Hard Disk Drive, Tape Drive Largest capacity, usually the lowest R/W speed, lowest portability and durability (due to moving parts), cheapest

Question 27

Storage type : Optical

Answer 27

e.g. Blu-ray, DVD ROM, CD ROM Lowest capacity, medium reliability (approx 10 years)

Question 28

Storage type : Solid state

Answer 28

e.g. Solid State Drive, SD Card, USB Memory Stick Fastest R/W speed, best portability and durability (due to no moving parts), USBs are typically used for reliability, most expensive

Question 29

Compression

Answer 29

Making the size of a file smaller To save on storage space, costs and time for uploads/downloads

Question 30

Lossy compression

Answer 30

When the file is decompressed - data has been lost Not suitable : Text files and code Suitable : Images, videos, sound Creates smaller compressed files than lossless compression

Question 31

Lossless compression

Answer 31

When the file is decompressed 0 - no data has been lost Suitable : Text files and code

Question 32

LAN (Local Area Network)

Answer 32

A network of connected computers in a limited geographical area where the equipment used is typically owned by the organisation

Question 33

WAN (Wide Area Network)

Answer 33

A network of connected networks in a large geographical area where the equipment used is typically rented by the organisation

Question 34

Bandwidth

Answer 34

The amount of data that can be transferred through a specific connection in a given amount of time, measured in bits per second

Question 35

Amount of traffic

Answer 35

Number of devices attached As the amount of network traffic increases then the share of the available bandwidth decreases