1.2 Memory and Storage

Question 1

Primary Storage

Answer 1

Memory that the CPU can access very quickly

Question 2

Need for primary storage

Answer 2

For data it needs to access quickly

Question 3

Examples of things stored in primary storage

Answer 3

Operating System
BIOS
Boot up instructions

Question 4

Types of primary storage

Answer 4

ROM
RAM

Question 5

Purpose of ROM in a computer system

Answer 5

Non - volatile
Contains BIOS for the boot process

Question 6

Purpose of RAM in a computer system

Answer 6

Volatile
Operating system is copied into RAM from secondary storage when computer boots up
CPU can access quickly - stores data, files, and programs that are being used

Question 7

ROM full form

Answer 7

Read-only memory

Question 8

RAM full form

Answer 8

Random access memory

Question 9

Volatile memory

Answer 9

Temporary
Needs power to retain data

Question 10

Non - volatile memory

Answer 10

Permanent
Retains. data when there is no power

Question 11

BIOS

Answer 11

Basic Input Output System
Instructions a computer needs to properly boot up

Question 12

Virtual Memory

Answer 12

When RAM gets full, the computer moves less recently used data into a section of secondary storage (virtual memory)

For the CPU to read data in virtual memory, it needs to be swapped back into RAM

Question 13

When is virtual memory needed?

Answer 13

When too many applications are running at once

Question 14

Disadvantage of Virtual Memory

Answer 14

Makes a computer slow to respond when switching between applications (swapping them in and out of RAM)

Question 15

Secondary Storage

Answer 15

Where data is stored when not in use

Question 16

Need for secondary storage

Answer 16

To store files and programs

Question 17

Common types of secondary storage

Answer 17

Optical
Magnetic
SSD
HDD

Question 18

Hard Disk Drives (HDDs)

Answer 18

Stack of magnetised metal disks that spin
Have a read-write head which can read + write data

Question 19

Solid State Drives (SSDs)

Answer 19

No moving parts = silent
Use a type of flash memory
Higher read-write speed than HDDs

Question 20

Advantages of HDDs

Answer 20

Cheap
High capacity
Longer read-write life than SSDs

Question 21

Advantages of SSDs

Answer 21

Faster
Don’t need to be defragmented (slows them down!)
Shock - proof
Silent

Question 22

Optical Storage

Answer 22

Uses light to store data

Question 23

Examples of optical discs

Answer 23

CD
DVD
Blu-ray

Question 24

Types of Optical Discs

Answer 24

Read only (e.g. CD-ROM)
Write once (e.g. CD-R)
Rewritable (e.g. CD-RW)

Question 25

Why use of optical discs is declining

Answer 25

Streaming services have become popular e.g. Netflix Modern devices e.g. phones don't have optical drives

Question 26

Disadvantages of Optical Storage

Answer 26

Low capacity Slow read/write speed Poor reliability Scratches

Question 27

Advantages of Optical Storage

Answer 27

Cheap Portable Not affected by water or shock

Question 28

Advantages of Magnetic Tapes

Answer 28

Large capacity Cheap Fast rad/write speed

Question 29

Where are magnetic tapes used?

Answer 29

In archives of large organisations

Question 30

Disadvantages of Magnetic Tape

Answer 30

Read/write sequentially -> difficult to find a specific piece of data on it

Question 31

Bit

Answer 31

Single binary digit (1 or 0)

Question 32

Nibble

Answer 32

4 bits

Question 33

Byte (B)

Answer 33

8 bits

Question 34

Kilobyte (KB)

Answer 34

1000 Bytes

Question 35

Megabyte (MB)

Answer 35

1000 Kilobytes

Question 36

Gigabyte (GB)

Answer 36

1000 Megabytes

Question 37

Terabyte (TB)

Answer 37

1000 GIgabytes

Question 38

Petabyte (PB)

Answer 38

1000 Terabytes

Question 39

Why does data need to be converted to binary so that the computer can read it?

Answer 39

Computers only process binary digits Binary digits represent the flow of electricty

Question 40

How do computers process alphanumerical character?

Answer 40

Character sets

Question 41

Character Set

Answer 41

A collection of characters that a computer recognises due to their binary representation More number of bits per character = more characters

Question 42

What happens when you press a key on your keyboard?

Answer 42

Sends a binary signal to the computer telling it which key was pressed The computer uses the character set to translate it into binary

Question 43

Examples of Character Sets

Answer 43

ASCII Unicode

Question 44

ASCII

Answer 44

7-bit binary code -> 128 characters

Question 45

Unicode

Answer 45

Covers all major symbols and languages Uses multiple bytes First 128 codes are the same as ASCII

Question 46

How are images stored?

Answer 46

Made up of pixels

Question 47

Types of images

Answer 47

Bitmap Vector

Question 48

What is the colour of each pixel represented by?

Answer 48

Binary

Question 49

Colour Depth

Answer 49

The number of bits used for each pixel

Question 50

How to work out the total number of colours

Answer 50

2*n(number of bits per pixel)

Question 51

Image Resolution

Answer 51

Number of pixels in the image

Question 52

How to work out image resolution

Answer 52

Width x Height

Question 53

How does colour depth and resolution effect the quality of the image?

Answer 53

Higher resolution and higher colour depth = better quality of image

Question 54

How to work out file size

Answer 54

Image resolution x colour depth Width x height x colour depth

Question 55

Metadata

Answer 55

Data about data Information stored in an image which helps the computer recreate the image on screen

Question 56

Examples of things stored in metadata

Answer 56

File format Height Width Colour Depth Resolution

Question 57

Sampling

Answer 57

The process of converting from analogue to digital

Question 58

How can analogue sound be converted into digital data?

Answer 58

Analogue to digital converters

Question 59

Sample Rate

Answer 59

How many samples are taken in a second In Hz

Question 60

Bit depth

Answer 60

Number of bits available for each sample

Question 61

How to calculate file size

Answer 61

Sample Rate x Bit Depth x Length

Question 62

How does sample rate + bit depth effect the playback quality

Answer 62

Higher sample rate = better quality Higher bit depth -> the digital file also picks quieter sounds = better quality

Question 63

How does sample rate + bit depth effect file size

Answer 63

Higher bit depth + sample rate = higher file size

Question 64

Data Compression

Answer 64

To make file sizes smaller

Question 65

Uses of Data Compression

Answer 65

Takes up less storage Streaming + downloading files from the Internet is quicker as less bandwidth is used Web pages download quicker Email services have restrictions on file size

Question 66

Types of Compression

Answer 66

Lossy Lossless

Question 67

Lossy Compression

Answer 67

Permanently removes data from the file

Question 68

Lossless Compression

Answer 68

Temporarily removes data from the file to store it, and restores it when it is opened

Question 69

Advantages of Lossy

Answer 69

High file size reduction Use up less bandwidth -> can be streamed and downloaded quickly Commonly used

Question 70

Disadvantages of Lossy

Answer 70

Loses data -> file cannot be reverted back to the original Cannot be used on text files Highly reduce quality of image

Question 71

Examples of Lossy file types

Answer 71

MP3 AAC JPEG

Question 72

Advantages of Lossless Compression

Answer 72

Data is only removed temporariliy -> when opened there is no reduction in quality Can be used for text files

Question 73

Disadvantages of Lossless Compression

Answer 73

Only slight reduction in file size

Question 74

Examples of Lossless file types

Answer 74

FLAC TIFF PNG