1.2.2 Secondary Storage Flashcards
Secondary storage
It is non-volatile storage - where all the data (OS, applications and user files) are stored when processor is not in use.
Why do you need secondary storage?
Because ROM is read only and RAM is volatile.
What is secondary storage needed for?
-Storage of programs and data when power is turned off
-Semi-permanent storage of data that can be changed
-Backup of data files
-Archive of data files
What are the common types of secondary storage?
-Optical storage
-Magnetic storage
-Solid state
Examples of optical storage:
-CD-R/RW
-DVD-R/RW
-Blu-ray
Examples of magnetic storage
-Hard disk drive
-Tape
What is solid state storage?
A type of non-volatile media that uses electronic circuits to store binary 0s and 1s.
What is magnetic storage?
A type of non-volatile media that uses magnets (polarity) to store binary 0s and 1s.
What is optical storage?
A type of non-volatile media that uses lasers to burn the surface of a disk, creating pits and lands suitable for storing binary 0s and 1s.
Examples of solid state
-SSD
-Memory sticks
-Flash memory cards
-USB flash drive
What are the advantages of HDDs compared to SSDs?
-They are cheaper
-HDDs have higher capacity than SSDs
-Have a longer read/write life than SSDs (SSDs can only be written a certain number of times before they begin to deteriorate)
What are the advantages of SSDs compared to HDDs?
-They are faster
-They don’t need defragmenting
-SDDs are more shock proof than HDDs
-HDDs make more noise, SDDs are silent
What three forms does optical storage come in?
-read-only (e.g. CD-ROM)
-write-once (e.g. CD-R)
-rewritable (e.g. CD-RW)
Why are optical discs declining?
DVD-Rs and DVD-RWs used to be popular for backing up data, but they have low capacity per disc, very slow read/write speeds and poor reliability compared to flash storage devices.
Advantages of solid state:
-Capacity - Medium/high storage
-Speed - Very fast read/write access
-Durability - No moving parts
-Portability - Small and no moving parts
-Noise - Silent
Disadvantages of solid state:
-Reliability - Limited read/write cycles
-Cost - Very high per gigabyte
Advantages of optical storage?
-Cost: They are very cheap (per GB).
-Portability: Small and no moving parts
-Durability: Won’t be damaged by water or shocks, no moving parts.
-Noise: Silent
Disadvantages of optical storage?
-Speed: Slow read/write speed
-Reliability/Durability: Not durable/reliable as discs are very fragile and can break or scratch easily
Advantages of Magnetic storage:
-Capacity - High storage
-Cost - Low per gigabyte
-Speed - Moderate read/write access
Disadvantages of Magnetic storage:
-Portability - Heavy & bulky making them less convenient for transport
-Durability - Moving parts can get damaged if dropped
-Reliability - Prone to mechanical failure
-Noise - Loud (spinning disks)
Average read/write speed from slowest to fastest:
Optical disc -> Memory Card -> Magnetic Tape -> HDD -> SSD
Average cost from cheapest to most expensive:
Magnetic Tape -> Optical disc -> HDD -> Memory Card -> SSD
Average capacity from lowest to highest:
Optical disc -> Memory Card -> SSD -> HDD -> Memory Tape
