Data Storage

Question 1

what is meant be primary storage

Answer 1

directly accessible by the CPU

Question 2

secondary storage definition

Answer 2

not directly accessed by CPU - more permanent data storage

Question 3

what is RAM used for

Answer 3

• temporarily store instructions + data whilst computer in operation
• copied from hard disk into main memory

Question 4

is RAM volatile or non-volatile and why does it mean

Answer 4

Volatile - gets wiped as soon as power switched off

Question 5

is ROM volatile or non-volatile and why does it mean

Answer 5

Non-volatile - Data permanently retained without power

Question 6

what does ROM stand for

Answer 6

Read Only Memory

Question 7

can ROM be overwritten

Answer 7

NO: read-only
- cannot be changed after being set by manufacturer

Question 8

what is ROM memory used for

Answer 8

• computer start up instructions
• embedded systems

Question 9

what storage types does secondary storage include

Answer 9

• Hard drives
• USB flash drives
• CDs

Question 10

is secondary storage volatile or non-volatile

Answer 10

non-volatile

Question 11

what is secondary storage best for

Answer 11

longer term storage of files + data - will remain when power off

Question 12

what type of storage media would you use in a laptop or tablet device. and why?

Answer 12

Solid State Drives (SSDs):
- require very little power
- create little heat - lack of moving parts –> small + reliable
- portable

Question 13

what are the adv of SSDs over HDDs

Answer 13

• 100x faster
• do not require expensive cooling equipment

Question 14

where are SSDs used

Answer 14

• laptops
• tablets
• smartphones
• desktop + larger computer systems

Question 15

what are the adv of HDDs

Answer 15

• cheaper

Question 16

where are HDDs often used

Answer 16

Desktop computers

Question 17

what are USBs best used for

Answer 17

regular backup of small files - more durable

Question 18

what are CDs and DVDs used for

Answer 18

for music + video storage in short + medium term - 10-25 yrs

Question 19

describe the operation of SSDs

Answer 19

• uses NAND or NOR gates in electrical circuits to store data
• these use transistors as control gates and floating gates to control flow of current
• current flowing = 1, no current = 0

Question 20

how do optical drives work (CDs / Blu-ray)

Answer 20

• uses laser to reflect light off the surface of the disk
• one long spiral track contains pit and lands
• when laser beam hits curved start or end of pit –> light refracted and 1 recorded
• where light reflected back directly from flat pit / land = 0 recorded

Question 21

describe the operation of a HDD

Answer 21

• data stored on magnetic patters , divided into tracks and sectors
• Data is read and written
  using electromagnets
• iron particle on disk magnetised to be either north or south = 0 or 1

Question 22

what are the moving parts in a HDD

Answer 22

• drive read/write head moves into position - movement takes time
• drive spindle rotates disk

Question 23

what are the disadvantages of moving parts

Answer 23

• easily damaged + issues if dropped
• overheating

Question 24

what is virtual memory

Answer 24

small section in hard disk used when not enough space in RAM for all programs + data currently working on

Question 25

describe the process when data needs to be moved into the virtual memory. Example using Windows, Word, Word document

Answer 25

- Windows, Word, Word document opened and **loaded into RAM** from the **hard disk** - **fills up RAM** - if Excel required, **CPU** must first **transfer pages of data** that compromise Word **out of RAM into virtual memory** - to free up space - RAM is **divided into fixed sized pages** (4KiB) - file currently in **RAM** may be help in **several non-contiguous** pages

Question 26

what saves the number and location of each page

Answer 26

page table

Question 27

what is cloud storage

Answer 27

**remote file storage** - accessed remotely in comparison to storing data locally - often include ***major 3rd party** - Google, Microsoft

Question 28

what is needed for cloud storage

Answer 28

Physical servers + storage

Question 29

Adv of cloud storage compared to local storages

Answer 29

- **No need to purchase** local storage devices / **employ maintenance staff** - online storage can **shrink or grow** as you need it - **greater fault tolerance** - all hardware + backup issues handled **externally** - **Remote access** to files from **any Internet connected device** - anywhere in world - enables **file sharing + collaboration** - **more environmentally friendly**

Question 30

Disadvantages of cloud compared to local storage

Answer 30

- may need **annual subscription** - **Backup + restore may be slower** depending on **internet connection speed** - **security of data managed by 3rd party** - outside of user's control - **need internet connection** - **your responsible for security breaches** over data - even though you have no control over security

Question 31

what does NIC stand for

Answer 31

Network Interface Cards

Question 32

what are NICs used for

Answer 32

NICs are **physical component** required to connect to any **network enable device** - e.g. home computers, smartphones, printers

Question 33

what are NICs

Answer 33

a physical component needed to operate with **wireless connection** or **wired connection using Ethernet cable**

Question 34

what is a MAC address

Answer 34

- used to identify device with **unique hexadecimal identification number** - assigned to every **network interface card** used in networked devices

Question 35

will MAC address change

Answer 35

NO - **IP address** may change - **MAC address** is **set by the manufacturer** and is **static** - same forever

Question 36

hat do the first 3 bytes represent in a MAC address

Answer 36

unique manufacture's code

Question 37

hat do the last 3 bytes represent in a MAC address

Answer 37

unique serial code