1.2 Memory and storage

Question 1

What is primary storage ?

Answer 1

Memory that the CPU can read/write to quickly

Question 2

What is volatile ?

Answer 2

Power is required to for the component to retain it’s data

Question 3

What is non-volatile ?

Answer 3

The component retains data even without power

Question 4

What is RAM ?

Answer 4

The computers main memory

Question 5

What is the purpose of RAM ?

Answer 5

Holds data and programs that are currently in use

Question 6

Is RAM volatile or non-volatile ?

Answer 6

Volatile

Question 7

What are 2 examples of primary storage ?

Answer 7

RAM and ROM

Question 8

What is the purpose of ROM ?

Answer 8

Stores the BIOS / the instructions needed to boot up the computer

Question 9

Is ROM volatile or non-volatile ?

Answer 9

Non-volatile

Question 10

What is the purpose of virtual memory ?

Answer 10

When RAM is full, some data is moved to virtual memory as a temporary storage and when that data is needed it is moved back to RAM

Question 11

Why does virtual memory cause the computer to slow down ?

Answer 11

Because data is transferred from virtual memory back to RAM instead of the data already being on RAM making it slower

Question 12

What is secondary storage ?

Answer 12

Where data and programs are stored when they are not being used

Question 13

What are 3 types of secondary storage ?

Answer 13

Solid state
Optical
Magnetic

Question 14

What are 4 features of magnetic storage ?

Answer 14

Moving parts - unreliable / less durable
Can be noisy
Large amounts of capacity
Cheap

Question 15

What are 4 features of optical storage ?

Answer 15

Disks are easily starched - unreliable / not durable
Cheap
Low capacity
Slow speeds

Question 16

What are 4 features of solid state storage ?

Answer 16

No moving parts - reliable and durable
Expensive
Good capacity
Fast speeds

Question 17

What type of data can computers only understand ?

Answer 17

Binary

Question 18

How does binary data work ?

Answer 18

Represented by 1s (show electricity is flowing)
and 0s (shows electricity isn’t flowing)

Question 19

What are the 8 units of data size ?

Answer 19

Bit
Nibble
Byte
Kilobyte
Megabyte
Gigabyte
Terabyte
Petabyte

Question 20

What is a bit ?

Answer 20

A single binary digit (1 or 0)

Question 21

How many bits are in a nibble ?

Answer 21

4

Question 22

How many bits are in a byte ?

Answer 22

8

Question 23

How do you calculate sound file size ?

Answer 23

Sample rate x duration x bit depth

Question 24

How do you calculate text file size ?

Answer 24

Bits per character x number of characters

Question 25

How do you calculate image file size ?

Answer 25

Image width x image height x colour depth

Question 26

What is an overflow error ?

Answer 26

When binary arithmetic gives out a result which is more bits than the cpu was expecting

Question 27

How do you go from hexadecimal to denary ?

Answer 27

Put number in hexadecimal place value table Multiply the values in each column Add the results

Question 28

How do you go from denary to hexadecimal ?

Answer 28

Divide by 16 to get answer and remainder Convert answer and remainder to hexadecimal The answer is 1st digit Remainder is 2nd digit

Question 29

How do you go from binary to hexadecimal ?

Answer 29

Split the binary number into 4 bits each Put 1 of the 4bit numbers in 2 tables that have 8,4,2,1 Same as normal binary to denary Convert your 2 4bit numbers into hexadecimal

Question 30

How do you go from hexadecimal to binary ?

Answer 30

Convert each hexadecimal digit into 4 bit binary Put the 2 4bit numbers together

Question 31

What are binary shifts ?

Answer 31

Move every bit in a binary number left or right a certain amount of times and fill in any gaps on the ends with a 0

Question 32

What happens if it is a left shift ?

Answer 32

The number is multiplied (Every place shifted left number is doubled so 2 shifts is 2 squared = 4)

Question 33

What happens if it is a right shift ?

Answer 33

The number is divided (Every place shifted right number is halved)

Question 34

How are characters represented in binary ?

Answer 34

With character sets

Question 35

What is a character set ?

Answer 35

Collections of characters that a computer recognises from the binary representation

Question 36

What are the 2 types of character sets ?

Answer 36

ASCII and unicode

Question 37

What are 3 features of ASCII ?

Answer 37

Each character is given 7 bit binary code 128 different characters possible Numbers and letters are ordered (A,B,C / 1,2,3)

Question 38

What are 3 features of unicode ?

Answer 38

Converts lots of different languages More characters possible than ASCII Fist 128 characters are same as ASCII

Question 39

What is a bitmap ?

Answer 39

An image made up of lots of tiny dots called pixels

Question 40

What is special about each individual pixel ?

Answer 40

Each pixel has a specific colour represented by a specific code

Question 41

How do you calculate total number of colours ?

Answer 41

2 to power of n (n = colour depth)

Question 42

What is metadata ?

Answer 42

Additional information about the image such as height, width and date q

Question 43

What affect does a greater colour depth and resolution have on the size and quality of the image ?

Answer 43

Bigger size and better quality

Question 44

What is sampling ?

Answer 44

Converting an analogue sound wave into binary data

Question 45

What is sample rate and what is it measured in ?

Answer 45

Number of samples taken per second and measured in hertz

Question 46

How do you sample sound ? (2 steps)

Answer 46

Amplitude of sound wave is measured at set intervals Sound is then recreated digitally but may have lost some accuracy

Question 47

What is bit depth ?

Answer 47

Number of bits available to store each sample

Question 48

What is data compression ?

Answer 48

Making files smaller whilst trying to stay as true to the original as possible

Question 49

What is 1 benefit of data compression ?

Answer 49

Compressed files use less storage

Question 50

What are 2 types of compression ?

Answer 50

Lossy and lossless

Question 51

What is lossy compression ?

Answer 51

When data is permanently removed from the file

Question 52

What is lossless compression ?

Answer 52

Temporarily removes data from a file but restores it to original when opened

Question 53

What are 2 benefits of lossy compression ?

Answer 53

Big reduction size Commonly used

Question 54

What are 2 benefits of lossless compression ?

Answer 54

No reduction in quality Files can be turned back to original

Question 55

What are 2 drawbacks of lossy compression ?

Answer 55

Permanently loses data Reduction in quality

Question 56

What are 2 drawbacks of lossless compression ?

Answer 56

Take up more storage than lossy Small reduction size