Secondary Storage

Question 1

examples of optical discs

Answer 1

CDs, DVDs and Blu-ray discs

Question 2

storage of CDs, DVDs and Blu rays

Answer 2

CDs - 700MB
DVDs - 4.7GB
Blu rays - 25GB

Question 3

forms of optical disks

Answer 3

• read only (CD ROM, DVD ROM)
• write once (CD-R, DVD-R)
• re writable (CD-RW, DVD-RW)

Question 4

why is optical disks use declining?

Answer 4

• internet speeds have increased, streaming and downloading services (netflix, itunes)
• phones and tablets don’t have optical drives
• DVD-Rs and DVD-RWs can’t compete with flash storage devices due to their low capacity per disc and slow read/write times

Question 5

advantages of optical discs

Answer 5

• cheap
• portable
• won’t be damaged by water or shocks

Question 6

properties of magnetic tape

Answer 6

• much greater storage capacity than HDDs
• low cost per GB
• used by large organisations in archive libraries to tore huge amounts of data
• comes in plastic cassettes, need special tape-drive for read/writing

Question 7

how are magnetic tapes read/written?

Answer 7

sequentially, so it’s read/written from the start to end, or until it’s stopped by the computer. This means the tape is very slow when finding specific data stored on it, but has fast read/write speed once it’s in correct place to begin reading/writing