memory& storage

Question 1

primary storage

Answer 1

Very quick because it is directly accessed by the CPU.
Typically smaller in storage size.
Sometimes called “main memory”
e.g. RAM ROM

Question 2

secondary storage

Answer 2

Slower as it isn’t directly accessed by the CPU.
Typically larger in storage size
Used for long term storage of data because it is non-Volatile.
Includes magnetic, optical and solid state storage
access time is slower than primary as it is not directly embedded on the motherboard or could even be external and therefore further away from the CPU.

Question 3

volatile and non-volatile

Answer 3

volatile- temporary, data is lost whenever the power is turned off.

non-volatile- saves the data even when not being powered. data can be stored long term and accessed when the computer is switched on.

Question 4

random access memory

Answer 4

volatile storage that stores all programs that are currently running. it also stores parts of the operating system to be accessed by the CPU.

RAM is made up of a large number of storage locations, each can be identified by a unique address.

Question 5

read only memory

Answer 5

non-volatile storage that cannot be changed.

ROM stores the boot program for when the computer is switched on. the boot program then loads up the operating system to take over managing the computer.

Question 6

virtual memory

Answer 6

when there is insufficient space in RAM for all programs the computer can use the hard disk drive as an extension RAM- this is called virtual memory.

If new data is needed to be stored in RAM then unused data in RAM is moved to the hard drive so the new data can be transferred into RAM.

Question 7

secondary storage characteristics

Answer 7

capacity-the maximum amount of data that can be stored

durability- strength of the device, to last without breaking.

portability- how easy data on the device can be read or edited.

access speed-speed that the data on the device can be read or edited.

cost-average price it costs to buy a storage device

reliability- the likelihood of the device continuing to perform well over time.

Question 8

magnetic storage

Answer 8

large capacity and cheaper cost per gigabyte than solid state.

not durable and not portable when powered on as it could damage the device.

slow access speed but faster than optical storage.

Question 9

optical storage

Answer 9

discs are thin and portable. also very cheap in bulk(e.g. CD, DVD, blu-ray)

low capacity

not durable- very fragile

optical disks have the slowest access speed

Question 10

American standard code for information interchange

Answer 10

it uses 8 bits which only gives 256 possible characters.
only enough for the english language but it cant be used for other language or all punctuation symbols

Question 11

unicode

Answer 11

16 bits, allows 65,536 possible characters.

requires more memory to store each character than ASCII as it uses extra byte.

Question 12

file size

Answer 12

file size= resolution x colour depth

Question 13

sample rate

Answer 13

amount of times per second the amplitude of the sound wave is measured.
it is measured in kilohertz

Question 14

bit depth

Answer 14

the number of bits available to represent each sample.
The higher the bit depth, the more bits are available to be used for each sample.

Question 15

calculating sound file size

Answer 15

sound file=sample rate x bit depth x duration

Question 16

lossy compression

Answer 16

can reduce the file size by a large amount as it will remove data that human can see or hear.
Removes the data permanently, so the file can never return to its original form.

Question 17

lossless compression

Answer 17

reduces file size with out permanently removing any data. because of this, the file is returned to its original form when decomposed

-reconstructs the data