1.2 Memory and Storage

Question 1

What is Primary storage?

Answer 1

Holds the data and instructions which the CPU needs access to while a computer is running.
–> CPU can access data quicker from
primary than secondary

Question 2

Examples of primary storages:

Answer 2

RAM
ROM
Cache & registers

Question 3

RAM

Answer 3

Holds the operating system, programs and data while the computer is running
.Volatile (content lost)
.Read and write
.Large compared to ROM

Question 4

ROM

Answer 4

Holds the first instructions for when the comp is turned on (bootstrap)
.Non-volatile (content remains)
.Read only
.Small compared to RAM

Question 5

Why is virtually memory needed?

Answer 5

When there is not enough physical RAM to store the open program

Question 6

Where is virtual memory held?

Answer 6

On the hard disk

Question 7

Virtual memory uses

Answer 7

Programs transferred out to VM from RAM when not being executed.

Program transferred back to RAM from VM when they’re needed.

Question 8

Why is secondary storage needed?

Answer 8

Because ROM is read only and RAM is volatile;
.storage of programs & data that can change
.backup of data file
.archive of data files

Question 9

What are the 3 types of secondary storage

Answer 9

• Optical (CD-R, Blue ray)
• Magnetic (Hard Disk Drive, Tape)
• Solid State (SDD, memory sticks)

Question 10

How do Optical storage work

Answer 10

Shining a laser at the media and processing the reflection of the media which can be determined by the pits and lands

Question 11

Optical Storage stats

Answer 11

Capacity= Low
Accessibility= Slow
Portability= Thin, light weight
Cost= Cheap
Reliability= Prone to scratches

Question 12

How does magnetic storage work?

Answer 12

Using the North and South pole of a magnet to store as 1 and 0

Question 13

Magnetic storage stats

Answer 13

Capacity= High
Accessibility= Quick
Portability= Fragile
cost = Cheap
Reliability= Moving parts (drive head) will
eventually fail

Question 14

How does Solid State storage work?

Answer 14

Flow of electricity forcing electrons into floating gates between 2 oxide layers causing a change in charge in the floating gate (can be measured in 1 and 0)

Question 15

Solid State pros and cons

Answer 15

Capacity= Medium
Accessibility= Very quick
Portability= portable
Cost= Expensive
Reliability= No moving parts
- no noise
- low power
- no need to defragment
- limited numbers of read/write cycles