1.2 Memory And Storage Part 2

Question 1

Denary/decimal/base10:

Answer 1

Standard number system, 10 digits

Question 2

Binary:

Answer 2

2 digits 0/1. Computers use this system as computers are made up of switches that can be turned on and off

Question 3

Overflow:

Answer 3

During binary arithmetic you could get a result that requires more bits than the CPU is expecting - this is called overflow

Question 4

Binary shift:

Answer 4

Moves every bit in a binary number left or right a certain number of places. Gaps at beginning or end filled with 0s

Question 5

Hexadecimal:

Answer 5

Base 16, uses 16 digits, 0-F(0-15) Large numbers can be written simply using Hex instead of binary

Question 6

Alphanumeric characters:

Answer 6

Used to make words and strings. Include uppercase and lowercase letters, digits 0-9 and symbols

Question 7

Character set:

Answer 7

Collections of characters that a computer recognises from their binary representation

Question 8

ASCII+ Extended

Answer 8

Most commonly used character set in English. ASCII uses 7 bits, extended ascii uses 8 bits. 2^7 = 128, extended is 256

Question 9

Unicode:

Answer 9

Uses 16 bits. Covers every possible character or symbol in all major languages.

Question 10

Pixel:

Answer 10

Smallest identifiable area of an image. Each pixel is a single colour and is given a binary value which represents a colour

Question 11

Colour depth:

Answer 11

Number of bits used for each pixel e.g. 2^2 = 4 colours

Question 12

Resolution:

Answer 12

No. of pixels in an image. Often given as Widthxheight

Question 13

Metadata:

Answer 13

Data stored in an image file about the picture

Question 14

Analogue:

Answer 14

Sound recorded by a microphone as an analogue signal. They are pieces of continually changing data

Question 15

Digital:

Answer 15

Analogue signals need to be converted into digital data so that computers can read and store sound files

Question 16

Hertz:

Answer 16

Frequency(Hz). Freq of 1Hz means something happens once per second

Question 17

Sound sampling:

Answer 17

Converting an analogue signal into a digital signal, called sound sampling. The amplitude of the wave is sampled at regular intervals

Question 18

Sample rate/frequency:

Answer 18

How many samples you take in a second. Hz, common sample rate is 44,100Hz

Question 19

Bit depth:

Answer 19

Number of bits available for each sample.

Question 20

File size:

Answer 20

File size(bits) = sample rate(Hz) x Bit Depth x Duration(s)

Question 21

Data compression:

Answer 21

Make files smaller. Try to make compressed file as close to the original as possible

Question 22

Lossy compression:

Answer 22

Removes data from the file. Reduces the number of bits in the file so file size lower. Cannot be returned to original.

Question 23

Lossless compression:

Answer 23

Uses an algorithm to find groups of repeating data. When data is uncompressed it is restored exactly as it was in the original.

Question 24

Bit depth in audio:

Answer 24

The accuracy of the sample’s representation of the original analogue signal