2 - Memory and Storage

Question 1

What is Binary and why is it important?

Answer 1

Combination of 1s and 0s
Information to be processed by computers must be converted to Binary format.
Numbers, text, sound images and program instructions are stored here.

Question 2

What is 1 bit?

Answer 2

0/1

Question 3

What is 1 byte?

Answer 3

8 bits.
stores characters of text

Question 4

What is a nibble?

Answer 4

4 bits

Question 5

What is 1 kilobyte

Answer 5

1000 bytes

Question 6

What is 1 megabyte?

Answer 6

1000 kilobytes

Question 7

What is 1 gigabyte?

Answer 7

1000 megabytes

Question 8

What is 1 terabyte?

Answer 8

1000 gigabytes

Question 9

What is a petabyte?

Answer 9

1000 terabytes

Question 10

What is denary?

Answer 10

Base 10 number system with 10 digits from 0-9 (one we normally use)

Question 11

How to convert from denary to binary?

Answer 11

Write out binary code from 1- 128 (from right to left). Fill in numbers that can add to make your number.
e.g. write 128 64 32 16 8 4 2 1
to get the number 45
00101101

Question 12

What is the largest number that can be stored in 8 bits?

Answer 12

2^8 - 1= 255

Question 13

What is the largest number that can be stored in 16 bits?

Answer 13

2^16 - 1= 65535

Question 14

How can we tell a binary number is even or odd.

Answer 14

Even - 0 at the end
Odd - 1 at the end

Question 15

What is hexadecimal?

Answer 15

Base 16 number system from 0-15
0123456789ABCDEF

Question 16

How do we convert hexadecimal to Denary

Answer 16

• the left number by 16 and + the right e.g.
  2A –> 2 * 16= 32 + 10( which A has value of) = 42

Question 17

How do we convert denary to hexadecimal?

Answer 17

/ by 16
Use remainder as units
e.g. 18 –> 18/16 = 1 remainder 2
12 in hex

Question 18

How do you convert binary to hexadecimal

Answer 18

Split binary number into 2 fours.
e.g. 11100101 —> 1110 and 0101
Convert each side to denary using scale from 1-8 (right to left) and cover that to hex
8421
1110 –> 14 = E
0101 –> 5 = 5
E5

Question 19

How do you convert from Hex to Binary?

Answer 19

Split into 2
e.g. 3B –> 3/B
Convert each side to binary using scale 1-8 (right to left)
3 = 0011 B = 1011
00111011

Question 20

What are the advantages of hexadecimal?

Answer 20

Easier to remember than binary
Quciker to write as only takes one digit not 4 bits.
Less errors with fewer digits
Easier to convert between hex and binary

Question 21

What are the rules of binary addition?

Answer 21

0+0=0
1+0=1
0+1=1
1+1=0 carry 1
1+1+1=1 carry 1

Question 22

What is overflow error?

Answer 22

9th bit in the addition.

Question 23

What is a binary shift?

Answer 23

Move all bits a place either left or right and fill in gaps with 0.
Multiplies when moving left e.g. double, quadruples e.t.c
Divides when moving right e.g. halves, quartrs e.t.c
Note when bits are removed a loss of accuracy occyrs.

Question 24

Explain characters on a keyboard

Answer 24

Each character has a binary value. Uppercase is different to lowercase. Punctuation have their own code.
There are 98 unique characters on a keyboard.

Question 25

What is the ASCII set?

Answer 25

American standard code for Information Interchange. Contains 428 characer incoded into 7 bit binary codes. a-z 97-122 A-Z 65-90 0-9 48-58 Originally 7 bits but now 8 bits used for special characters. 8 bits = 2^8= 256 different characters

Question 26

What is Unicode?

Answer 26

16 bits 65536 32 bits 4294967296 combos

Question 27

What are bitmage image files and give examples of their format?

Answer 27

Contain pixels (picture elements) which are the smallest indetifiable area of an image. One colour with binary value. Changing value changes colour. Examples: BMP,JPG,GIF,PNG,TIFF

Question 28

Give an example of a vector file format?

Answer 28

SVG

Question 29

What are the different file types?

Answer 29

Bitmage image and Vector

Question 30

What is resolution?

Answer 30

Concentration of pixels in area. Image width* height in pixels e.g. 1920 x 1080 72 ppi - pixels per inch 300 dpi - dots per inch Phones normally run at 300+ ppi

Question 31

How many bits can show how many colours?

Answer 31

1 bit = 2 (black and white) 2 bits = 4 e.t.c

Question 32

How does higher bit depth affect an image?

Answer 32

Higher bit depth = greater range of colour and better quality image. Example - 8 bits per pixel = 2^8 = 256 colours

Question 33

What is metadata?

Answer 33

Data about data. Information toher than image data stored with a file including: colour depth in pixels, resolution, data and author.

Question 34

What are the types of sound signals?

Answer 34

Analogue sound signals - Continous Digital signals - Discrete

Question 35

How and why do get sound on our devices?

Answer 35

Sound digitzed by repeatedly measuring and recording soundwave. ADC (analogue to digital converter) convert inputs to digital signal (microphone) DAC( digital to audio converter) converts digital to outputs (speaker) In digital form, sound can be stored and processed on a computer

Question 36

What are hz?

Answer 36

Measure of samples per second?

Question 37

What is resolution in terms of sound?

Answer 37

Audio bit depth. More bits means a more accurate measurement of wave height. This increases file size.

Question 38

What happens when we increase the frequency of the sound wave?

Answer 38

Increase accuracy Increase file size

Question 39

How do we calculate the filze size of a sound file?

Answer 39

Sample rate * bit depth * duration measured in bits

Question 40

What is lossy compression and why is it useful?

Answer 40

Removes unecessary sounds and is useful for storing, downloading and streaming. Convert 1 min of sound to 1mb of mp3 file which would otherwise be a 10mb uncompressed WAV file. Reduces file size.

Question 41

Examples of lossy files and disadvantages

Answer 41

JPG,GIF,MP3 Permanently loses data and can result in digital artefacts which are small mistakes in images and videos.

Question 42

What is lossless compression?

Answer 42

Reduces file size without losing info. Examples include FLAC, ALAC, PNG and TIFF

Question 43

General advantages of compression

Answer 43

Fast Download time reduced Further data allowances Quicker transmission Reduced internet traffic with reduced packets Reduce space on disk and server

Question 44

What is buffering?

Answer 44

When download speed is slower than playback speed.

Question 45

Explain what each of the following file types are used for: JPEG, PNG, ZIP, GIF, MP4, MP3, FLAC/ALAC

Answer 45

JPEG - photos PNG - photos/images ZIP - documents GIF - images and animation MP4 - videos MP3 - Music FLAC/ALAc - lossless music free/apple