Secondary Storage Flashcards
What are the 3 tiers of storage?
Primary-registers, cache, ROM, RAM, fast storage and mostly volatile
Secondary-non-volatile storage, Hard disk drives, solid state drives, CDs and SD cards. Much slower and where applications are stored when not in use
Tertiary storage-non volatile, stores data in the long term for example archives and back ups. A example is a magnetic tape library controlled by a robotic arm to access tapes
Describe a HDD
Traditional internal storage in PCs and laptops
Has a magnetic disk made of a stack of smaller ones, that spin at a speed of 5400-15000rpm.
Stored in areas called sectors within the circular track. Read/write heads on a moving arm are used to access sectors on the disk
HDDs are long lasting and reliable
What is a SSD or solid state drive?
They are storage devices with no moving parts and fulfill the same purpose of a HDD as internal storage
They are far faster reading and writing than HDD, so faster booting up and opening programs or files
What is a hybrid drive
They use A SSD for the OS and programs but then a HDD for data
Advantages of a HDD
Cheaper
HDD typically has higher capacity
Longer life span than a SSD tu can only read or write a certain amount of times before they start to deteriorate
Advantages of a SSD
They are far faster
They do not need defragmenting
They are more shock proof as they don’t have moving parts
SSDs are silent while HDDs make some noise
What is an optical disk
A form of secondary storage that can be used like a memory stick
How much data can a CD hold
700mb
How much data can a DVD hold
4.7 Gb
How much data can a Blu-ray hold
25Gb
Why are Optical drives becoming less relevant?
As internet speeds are improving all over the world streaming and download services are taking over and have removed the need for optical disk drives
They also were unreliable and had slow read and write speeds
What were the advantages of optical discs
They are very cheap
They are water proof
And are resistant to shocks
Why are magnetic tapes used
They are used for archiving
Why are magnetic tapes used?
Much greater storage capacity, and very low cost per gigabyte
Popular with large organisations to archive libraries to store huge amounts of data
What 2 unique feature does magnetic tape have
It comes in plastic cassettes that require a special drive for reading and writing
It can only be read from beginning to end or until stopped by computer, slow when finding specific data but fast when it’s in the correct place
