1.2 Memory and Storage

Question 1

ROM

Answer 1

Read Only Memory

Question 2

RAM

Answer 2

Random Access Memory

Question 3

What is RAM?

Answer 3

Main memory, primary memory, primary storage

Question 4

How is RAM used?

Answer 4

Can be written and read to. Much faster than a hard drive.

Question 5

What does the RAM store?

Answer 5

The OS (or part in use), the software currently in use and the data which the software is using

Question 6

Is RAM volatile?

Answer 6

RAM is volatile, which means that it loses data when power is turned off

Question 7

RAM when the computer is turned on

Answer 7

When the computer is first turned on, no data is stored in RAM

Question 8

The OS and RAM

Answer 8

The computer first loads the OS from the hard drive into RAM.

Question 9

Programs and data in RAM

Answer 9

When applications are loaded, they are copied into RAM from the hard drive. Documents and files that are used with those programs are also opened by copying them into RAM.
RAM starts to fill up as all these programs, documents and files are copied.

Question 10

Virtual memory

Answer 10

Is part of the hard drive and used as an extension to RAM

Question 11

Advantages of virtual memory

Answer 11

Uses cheap secondary storage on the hard drive, prevents error messages saying, ‘out of memory’ - the programs and files will still open

Question 12

Disadvantages of Virtual Memory

Answer 12

It is very slow to access as to access data, the existing data in RAM needs to be copied to the virtual memory, then data in virtual memory needs to be copied to RAM

Question 13

Characters -

Answer 13

simply letters, numbers and symbols

Question 14

Character set

Answer 14

all the set of all characters (letters, numbers, symbols) that a computer can understand.

Question 15

ASCII

Answer 15

uses 7-bits which could store 27 = 128 characters. ASCII was later upgraded to 8-bits which could store 28 = 256 characters.

Question 16

Unicode (16-bit and later 32-bit)

Answer 16

was brought in to allow other languages, with all their various letters and symbols to be able to be represented in a computer system.

Question 17

Resolution -

Answer 17

the number of bits per area of an image. Higher resolution = better quality (clearer).

Question 18

Colour depth (bit-depth) –

Answer 18

number of bits per pixel. Higher bit depth = more colours

Question 19

Sample rate/sampling frequency -

Answer 19

The number of samples of the sound taken per second.

Question 20

Bit depth or “sample size” -

Answer 20

The number of frequencies/pitches that can be represented. The higher the sampling frequency/sample rate and bit-depth/sample size the better the file will represent the original analogue sound.

Question 21

Bit rate:

Answer 21

The amount of data per second that is required to stream/play the sound back again.

Question 22

Metadata:

Answer 22

Data about data. For example, an image file might contain metadata that gives the resolution and colour depth.

Question 23

Binary shifts -

Answer 23

Binary shifts or “bit-shifts” moves binary numbers to the left or right. A shift of 1 space left will double the number. 1 shift right will halve it.

Question 24

Units of storage:

Answer 24

• Bit = 1 or 0 (smallest unit of data).
• Nibble = 4 bits
• Byte = 8 bits
• KiloByte = 1024 Bytes
• MegaByte = 1024 x 1024 (roughly 1 million) Bytes
• GigaByte = 1024 x 1024 x 1024 (roughly 1 billion) Bytes
• TeraByte = 1024 x 1024 x 1024 x 1024 (roughly 1 trillion) Bytes