1.2 Memory and Storage

Question 1

Why do computers need primary storage?

Answer 1

To allow fast access to the Cpu

Question 2

What is RAM?

Answer 2

Random access memory-Temporary volatile storage of instructions and data

Question 3

What is ROM?

Answer 3

Read only memory-Non volatile memory that contains information for a computers start up

Question 4

What is the difference between Ram and Rom?

Answer 4

Ram is volatile-Rom is non volatile
Ram is read and write-Rom is read only
Ram is temporary-Rom is permenant

Question 5

What is Virtual memory and why is it needed?

Answer 5

When Ram is full instructions are transferred to the Virtual memory

Question 6

What is the need for secondary storage?

Answer 6

Rom is read only and Ram is volatile so secondary storage is needed for:
The storage for data when the computer is switched off
Semi perminant storage of data
Back up of data files

Question 7

What is optical storage and the advantages and disadvantages?

Answer 7

Optical storage is CD,DVD and Blu Ray
It is very cheap,lightweight and portable however is slow to access and has low storage.

Question 8

What is magnetic storage and the advantages and disadvantages?

Answer 8

Magnetic storage is Hard disk drives and magnetic tape
It has a high storage,cheap and quick access however it has moving parts and are not durable

Question 9

What is solid state and the advantages and disadvantages?

Answer 9

Solid State is SSDs and USBs
It have good storage,quick access,robust and reliable however it is expensive

Question 10

State all the units of data storage in order and their values

Answer 10

Unit Symbol Binary Value
Bit b 0 or 1
nibble 4 bits
Byte B 8 bits
Kilobyte KB 1000 B
Megabyte MB 1000 KB
Gigabyte GB 1000 MB
Terabyte TB 1000 GB
Petabyte PB 1000 TB

Question 11

How do you calculate sound file size?

Answer 11

sample rate x duration x bit depth

Question 12

How do you calculate text file size?

Answer 12

bits per character x number per characters

Question 13

How do you calculate image file size?

Answer 13

colour depth x image height x image width

Question 14

What is 0100 1000 in Denary?

Answer 14

72

Question 15

What is 201 in Binary?

Answer 15

1100 1000

Question 16

What is 0110 1011 in Hex?

Answer 16

6B

Question 17

What is D5 in Denary?

Answer 17

213

Question 18

What happens when you do a binary shipt 2 places to the left?

Answer 18

You times by 4

Question 19

When you move 0110 2 places to the right it becomes 0001 Why?

Answer 19

There is an overflow error

Question 20

What are the different character sets?

Answer 20

ASCII and Unicode

Question 21

If A is represented as 0001 in Ascii what is B?

Answer 21

0010

Question 22

What is the difference between ASCII and extended ASCII?

Answer 22

ASCII is an eariler version with 7 bits however extended ASCII is a later version which is 8 bits and codes for other languages aswell

Question 23

How are images represented and what affects the file size?

Answer 23

Images are represented through bitmaps made up of different coloured pixels and the more pixels or colours the larger the file size.

Question 24

What is metadata?

Answer 24

Meta data is data abut data eg and image meta data would be the height, width or time taken

Question 25

How is sound represented and stored in digital form?

Answer 25

Sound is sampled and the sample rate is measured and converted into Binary

Question 26

How does the sample rate,duration and bit depth effect the sound quality and file size?

Answer 26

The higher the Bit depth and sample rate the better the quality howvere the longer the duration.higher the sample rate and higher the bit depth the bigger the file size.

Question 27

What is Lossy compression?

Answer 27

Compression that can be used on images or sound to significantly decrease the amount of storage needed however some of the data is lost

Question 28

What is Lossless compression?

Answer 28

Compression that is used on documents to slightly reduce the file size as it doesnt lose any data but encodes it differently

Question 29

What is the difference between Lossy and Lossless compression?

Answer 29

Lossy permenantly losses data however in lossless it can be changed back to its original form. Lossy is a lot more effient than lossless