1 Data Representation

Question 1

Uses of the hexadeciaml system (4)

Answer 1

error codes

MAC addresses

IP address

HTML colour codes

Question 2

What do the hex values of the error codes refer to

Answer 2

memory location of error

Question 3

What is a MAC address

Answer 3

uniquely identifies each device on a network

Question 4

How is a MAC address usually formatted?

Answer 4

6 groups of 2 hexadecimals

EG: NN - DD - NN - DD - NN - DD

Question 5

First half of the MAC address identifies the?

Answer 5

manufacturer

Question 6

Second half of the MAC address identifies the?

Answer 6

Serial number of the device

Question 7

Define IP address

Answer 7

unique numerical identifier assigned to devices connected to the internet, identifying their location

Question 8

What is IPv6

Answer 8

128 bits broken into 16 bit chunks by a hexadecimal number

Question 9

Features of ASCII code (3)

Answer 9

Uses 7 bits to represent characters

limited to 128 characters it can represent

Can only represent the english language

Question 10

Features of unicode (3)

Answer 10

Uses 16 bits to represent characters

Able to represent 65,536 characters

Can represent all languages in the world

Question 11

Define sample resolution

Answer 11

number of bits used to record each measurement during sampling

Question 12

Define sample rate

Answer 12

number of measurements taken per second

Question 13

Define sampling

Answer 13

A task performed by the ADC to represent analouge sound wave into a digital format

Question 14

what will using higher sample rate and larger sample resolution do to the orignal source (2)

Answer 14

more faithful representatiojn

larger file size

Question 15

Define pixel

Answer 15

smallest identifiable piece of an image

Question 16

What is a digital image

Answer 16

a series of pixels that are converted
to binary, which is processed by a computer

Question 17

Define image resolution

Answer 17

the number of pixels in an image

Question 18

Define colour depth

Answer 18

number of bits used to represent each colour

Question 19

What will increasing image resolution and colour depth do to the file? (2)

Answer 19

Better detail, more colours represented (higher qualiy)

larger file size

Question 20

How to calculate file size of an image

Answer 20

image resolution x colour depth

Question 21

How to calculate file size of sound

Answer 21

sample rate x sample resolution x length of track

Question 22

Write different units of data storage from smallest largest

Answer 22

bit (1 bit)

nibble (4 bits)

byte (8 bits)

kibibyte (1024 bytes)

mebibyte (1024 kibibytes)

gibibyte (1024 mebibytes)

tebibyte (1024 gibibytes)

pebibyte (1024 tebibytes)

exbibyte (1024 pebibytes)

Question 23

Reasons for data compression (3)

Answer 23

To save storage space devices

reduced file size reduces costs

reduce time taken to stream

Question 24

What are the two types of file compression (2)

Answer 24

Lossless file compression

Lossy file compression

Question 25

Features of lossy file compression (3)

Answer 25

alogirthm eliminates unnecessary data from file original file cannot be reconstructed once it is compressed Compression results in some loss of detail

Question 26

Examples of lossy file compression (3)

Answer 26

MP3 - Used for playing music MP4 - Allows storage of multimedia files JPEG - lossy file compression algorithm used for images

Question 27

Features of lossless file compression (2)

Answer 27

compression algorithm is used, repeated patterns in the file are identified and indexed original uncompressed file can be reconstructed

Question 28

Example of lossless file compression

Answer 28

RLE

Question 29

Features of RLE

Answer 29

indentifies and indexes repeating patterns (string of adjacent, identical data)