1.2 – Memory and storage

Question 1

What is the purpose of primary storage?

Answer 1

Primary storage is the computer’s workspace for actively running programs providing fast access to data and instructions currently in use by the CPU without it computers would be slower as CPU would need to constantly retrieve data from slower secondary storage

Question 2

What is RAM and its function?

Answer 2

Random Access Memory holds data and instructions the computer is currently working with such as the operating system running applications and open documents - RAM is volatile losing its contents when power is off

Question 3

What is ROM and its function?

Answer 3

Read-Only Memory stores essential firmware for booting and operating the computer - ROM is non-volatile and cannot be written to during normal operation

Question 4

What is virtual memory?

Answer 4

Virtual memory is part of secondary storage used as extra RAM when physical RAM is full - operating system swaps data not currently needed from RAM to virtual memory allowing more programs to run

Question 5

Why is secondary storage needed?

Answer 5

Secondary storage provides non-volatile long-term data storage so that data/files are retained when the computer is switched off

Question 6

Name three types of secondary storage.

Answer 6

Solid-state - Optical - Magnetic

Question 7

What is solid-state storage and its advantages?

Answer 7

Uses electrical circuits to persistently store data with no moving parts providing high read/write speeds suitable for portable devices

Question 8

What is optical storage and its uses?

Answer 8

Optical disks like CDs DVDs Blu-rays store data read by a laser - cheap per disk but low capacity and slower making them unsuitable for large-scale storage

Question 9

What is magnetic storage and its uses?

Answer 9

Uses tiny magnetised regions to store data often with moving parts - cheap and suitable for large backups but not portable

Question 10

Compare hard-disk drives

Answer 10

solid-state drives and optical disks for capacity

Question 11

Why do computers use binary?

Answer 11

Computers use binary because it has two states 0 and 1 mapping directly to electronic components like transistors making it simple to design hardware

Question 12

What is a bit nibble and byte?

Answer 12

Bit is 1 binary digit - nibble is 4 bits - byte is 8 bits

Question 13

What are KB MB GB TB PB?

Answer 13

Kilobyte 1000 bytes - Megabyte 1000 KB - Gigabyte 1000 MB - Terabyte 1000 GB - Petabyte 1000 TB

Question 14

How is the size of sound files calculated?

Answer 14

Sample rate × duration in seconds × bit depth

Question 15

How is the size of image files calculated?

Answer 15

Colour depth × image height in pixels × image width in pixels

Question 16

How is the size of text files calculated?

Answer 16

Bits per character × number of characters

Question 17

What is decimal (base 10)?

Answer 17

Number system humans use counting with digits 0 to 9 each digit having place value based on powers of 10

Question 18

What is binary (base 2)?

Answer 18

Number system with digits 0 and 1 each digit having place value based on powers of 2

Question 19

What are the most significant and least significant bits?

Answer 19

Most significant bit is leftmost 1 with highest value - least significant bit is rightmost bit with lowest value

Question 20

How do you convert binary to decimal?

Answer 20

Add together the place values for every binary 1 using powers of 2

Question 21

How do you convert decimal to binary?

Answer 21

Use place value headers starting from the highest power of 2 placing 1 if value ≤ number subtracting and continuing until number is 0

Question 22

What are the rules for binary addition?

Answer 22

0+0=0 - 1+0=1 - 1+1=0 carry 1 - overflow error occurs if result exceeds available bits

Question 23

What is hexadecimal (base 16)?

Answer 23

Uses digits 0-9 and letters A-F representing decimal 0-15 each hex digit represents 4 bits

Question 24

What is a binary shift and why is it used?

Answer 24

Moving bits left or right losing bits at end zeros added at opposite end - left shift multiplies by 2 for each place - right shift divides by 2 for each place - used in graphics bitmasking compression encryption

Question 25

What is character encoding?

Answer 25

Process of converting letters numbers symbols into binary codes for computer processing

Question 26

What is ASCII and Unicode?

Answer 26

ASCII uses 8 bits per character for standard characters - Unicode uses 8 to 32 bits allowing more characters from other languages and emojis

Question 27

How do you calculate text file size with character encoding?

Answer 27

Bits per character × number of characters

Question 28

What is a digital image pixel?

Answer 28

Smallest point in an image storing a colour value in binary

Question 29

What is colour depth?

Answer 29

Number of bits assigned to a pixel determining how many colours it can represent

Question 30

What is image resolution?

Answer 30

Number of pixels in an image found by multiplying image width by height

Question 31

What is image metadata?

Answer 31

Data about an image such as file format resolution colour depth and device used

Question 32

How do you calculate image file size?

Answer 32

Colour depth × image height × image width

Question 33

How do resolution and colour depth affect image quality and file size?

Answer 33

Higher resolution and higher colour depth increase quality and file size

Question 34

What is analogue and digital sound?

Answer 34

Analogue sound is continuous wave - digital sound samples the wave at points stored as binary

Question 35

What is sampling rate and bit depth in sound?

Answer 35

Sampling rate is number of samples per second in hertz - bit depth is number of bits used per sample

Question 36

How do you calculate sound file size?

Answer 36

Sample rate × duration × bit depth and divide by 8 for bytes

Question 37

How do sampling rate and bit depth affect sound quality and file size?

Answer 37

Higher sampling rate and bit depth increase playback quality and file size

Question 38

What is data compression?

Answer 38

Process of reducing file size without losing information or with minimal loss to save storage space and speed up transmission

Question 39

What is lossy compression?

Answer 39

Reduces file size losing some information quality slightly reduced irreversible used for images audio video

Question 40

What is lossless compression?

Answer 40

Reduces file size without losing information reversible uses algorithms to compress repeated patterns smaller reduction compared to lossy

Question 41

How do you convert binary to hexadecimal?

Answer 41

Divide by 16. The remainder is second digit. e.g 42 / 16 = 2r10 = 2A

Question 42

What is a nibble?

Answer 42

A nibble is 4 binary bits or half a byte

Question 43

After splitting binary into nibbles

Answer 43

what is the next step to convert to hex?

Question 44

How do you convert a decimal number to hexadecimal?

Answer 44

Convert the decimal number to its corresponding hex digit (0-9 or A-F)

Question 45

How do you form the final hexadecimal number after converting each nibble?

Answer 45

Concatenate all hexadecimal digits from each nibble to get the final hex representation

Question 46

Example: Convert 10110010 to hexadecimal

Question 47

How do you convert hexadecimal to binary?

Answer 47

Convert each hexadecimal digit to decimal - Convert decimal to 4-bit binary nibble - Combine all nibbles to form full binary number

Question 48

Example: Convert B2 to binary