C2 Memory and Storage

Question 1

Why do computers need primary storage?

Answer 1

To store data and programs that are actively being used so the CPU can access them quickly.

Question 2

What are the two main types of primary storage?

Answer 2

RAM (Random Access Memory) and ROM (Read-Only Memory).

Question 3

What is the purpose of RAM in a computer system?

Answer 3

RAM temporarily stores data and programs that are currently in use. It is volatile, meaning data is lost when power is off.

Question 4

What is the purpose of ROM in a computer system?

Answer 4

ROM permanently stores important instructions like the bootstrap loader. It is non-volatile.

Question 5

What are key characteristics of RAM?

Answer 5

Volatile, fast, temporary, read/write access.

Question 6

What are key characteristics of ROM?

Answer 6

Non-volatile, permanent, read-only, contains essential startup instructions.

Question 7

Why might virtual memory be needed?

Answer 7

When RAM is full, virtual memory allows the system to use part of the secondary storage to simulate extra RAM.

Question 8

How does virtual memory work?

Answer 8

Data not actively being used is moved from RAM to a section of the hard drive (virtual memory), freeing up RAM for active processes.

Question 9

What happens when RAM is full?

Answer 9

The system transfers data between RAM and secondary storage (virtual memory), which can slow performance.

Question 10

What is cache memory?

Answer 10

A small, very fast type of memory closer to the CPU that stores frequently used instructions and data.

Question 11

What’s the difference between RAM and ROM?

Answer 11

RAM is temporary and volatile, used for current tasks. ROM is permanent and non-volatile, used for essential startup instructions.

Question 12

Why do computers need secondary storage?

Answer 12

To store data and programs permanently for long-term access.

Question 13

What are the three main types of secondary storage?

Answer 13

Optical (e.g., CD), Magnetic (e.g., HDD), Solid State (e.g., SSD, USB).

Question 14

What are the characteristics used to compare storage types?

Answer 14

Capacity, speed, portability, durability, reliability, cost.

Question 15

Give an advantage of optical storage.

Answer 15

Cheap, portable, good for media distribution.

Question 16

Give a disadvantage of optical storage.

Answer 16

Easily damaged, slow access speed, low capacity.

Question 17

Give an advantage of magnetic storage.

Answer 17

High capacity, cost-effective.

Question 18

Give a disadvantage of magnetic storage.

Answer 18

Not very portable, mechanical parts = risk of damage.

Question 19

Give an advantage of solid-state storage.

Answer 19

Fast access speed, durable (no moving parts), portable.

Question 20

Give a disadvantage of solid-state storage.

Answer 20

More expensive per GB than magnetic storage.

Question 21

Which storage type is most suitable for a portable media player?

Answer 21

Solid-state — it’s small, fast, and durable.

Question 22

How do you compare devices in context?

Answer 22

Use CAPACITY, SPEED, DURABILITY, RELIABILITY, COST, and match to scenario needs.

Question 23

What are the units of data storage from smallest to largest?

Answer 23

Bit, nibble, byte, kilobyte, megabyte, gigabyte, terabyte, petabyte.

Question 24

Why must data be stored in binary format?

Answer 24

Because computers use transistors that can be on/off, representing 1s and 0s.

Question 25

How do you convert between data units?

Answer 25

Multiply or divide by 1024 (e.g., 1024 bytes = 1 KB).

Question 26

What is data capacity?

Answer 26

The amount of data a device or medium can hold.

Question 27

What affects the required storage capacity?

Answer 27

File size, number of files, file types (e.g., image vs. text), resolution, bit depth.

Question 28

How do you calculate the file size of text?

Answer 28

Number of characters × bits per character.

Question 29

How do you calculate the file size of an image?

Answer 29

Resolution (width × height) × color depth + metadata.

Question 30

How do you calculate the file size of sound?

Answer 30

Sample rate × duration × bit depth.

Question 31

What is the binary range for 8 bits?

Answer 31

0 to 255.

Question 32

What is the hexadecimal range for 8 bits?

Answer 32

00 to FF.

Question 33

What is a binary shift?

Answer 33

Moving bits left (×2) or right (÷2), affecting the value.

Question 34

How do you convert denary to binary?

Answer 34

Divide by 2, write down remainders, reverse them.

Question 35

How do you convert binary to hex?

Answer 35

Split binary into 4-bit chunks, convert each to hex.

Question 36

What is the most significant bit (MSB)?

Answer 36

The leftmost bit — has the highest value.

Question 37

What is the least significant bit (LSB)?

Answer 37

The rightmost bit — has the lowest value.

Question 38

What does a left binary shift do?

Answer 38

Multiplies the value by 2 for each shift.

Question 39

What does a right binary shift do?

Answer 39

Divides the value by 2 for each shift.

Question 40

What is a character set?

Answer 40

A collection of characters that a computer can recognise and use.

Question 41

What is ASCII?

Answer 41

A character set that uses 7 or 8 bits to represent English characters.

Question 42

What is Unicode?

Answer 42

A character set that uses up to 32 bits to represent many languages and symbols.

Question 43

Why does more bits per character = more characters?

Answer 43

Because each extra bit doubles the number of possible values.

Question 44

How are characters stored in binary?

Answer 44

Each character is assigned a unique binary code from the character set.

Question 45

How are character sets logically ordered?

Answer 45

Characters have ascending binary values in alphabetical/numerical order.

Question 46

What is a pixel?

Answer 46

The smallest unit of a digital image, each with a specific colour.

Question 47

How is an image stored in binary?

Answer 47

Each pixel’s colour is represented with binary values; metadata is added.

Question 48

What is color depth?

Answer 48

The number of bits used to represent each pixel’s colour.

Question 49

What is resolution?

Answer 49

The number of pixels in an image (height × width).

Question 50

What does increasing resolution or colour depth do?

Answer 50

Increases image quality AND file size.

Question 51

What is metadata in an image file?

Answer 51

Extra info like dimensions, colour depth, file format.

Question 52

How is sound stored in binary?

Answer 52

By sampling the amplitude of the sound wave at intervals and storing each sample as binary.

Question 53

What is sample rate?

Answer 53

The number of sound samples per second, measured in Hertz (Hz).

Question 54

What is bit depth?

Answer 54

The number of bits used to store each sound sample.

Question 55

How do sample rate, duration, and bit depth affect file size?

Answer 55

Higher values = better quality and larger file size.

Question 56

Why is compression needed?

Answer 56

To reduce file size for storage or faster transmission.

Question 57

What is lossy compression?

Answer 57

Permanently removes some data, reducing quality but also file size.

Question 58

What is lossless compression?

Answer 58

Compresses data without any loss in quality; can be restored to original.

Question 59

When would you use lossy compression?

Answer 59

For images, audio, or video where perfect quality isn’t essential (e.g., streaming).

Question 60

When would you use lossless compression?

Answer 60

For text or data files where all information must be preserved (e.g., software files).

Question 61

What are the pros and cons of lossy?

Answer 61

Smaller files, faster transfer, lower quality.

Question 62

What are the pros and cons of lossless?

Answer 62

No quality loss, but less file size reduction.