Secondary Storage Flashcards
When may virtual memory be needed?
When too many applications are open at once, or if a memory intensive application is being used.
What is virtual memory?
Data that is not frequently used moved to a location on secondary storage.
What is secondary storage?
Where all data is stored when not in use. It is also non-volatile.
What does HDD stand for?
Hard Disk Drive
What is a HDD made up of?
Magnetised metal disks spinning at 5400 to 15000 rpm
How is data on a HDD stored?
Magnetically in small areas known as sectors within circular tracks.
How is data read/written to a HDD?
With a read/write head on a moving arm to access sectors on the disks.
What does SSD stand for?
Solid State Drive
What do most SSDs use?
A type of flash memory
What are some examples of flash storage?
USB pen drives, memory cards
What are the advantages of HDDs over SSDs?
Cheaper, higher capacity, longer read/write life
What are the advantages of SSDs over HDDs?
Faster, don’t need defragmenting, more shock-proof, silent
What are some examples of optical disks?
CDs, DVDs and Blu-Ray
What is the capacity of a CD?
700MB
What is the capacity of a DVD?
4.7GB
What is the capacity of a Blu-Ray disk?
25GB
What are the advantages of optical disks?
Very cheap per GB, portable, won’t be damaged by water and shocks, however they are easily scratched.
What type of secondary storage typically gives the greatest capacity?
Magnetic tape
What type of secondary storage typically gives the smallest capacity?
Optical disk
What type of secondary storage typically is the cheapest?
Magnetic tape
What type of secondary storage typically is the most expensive?
SSDs
What type of secondary storage typically gives the greatest read/write speed?
SSDs
What type of secondary storage typically gives the slowest read/write speed?
Optical disks
