SLR 1.3 Storage Flashcards
What is a storage device?
Any medium (optical, magnetic, solid state and even paper which holds data or programs.
Which forms of storage are primary storage?
Any storage that the Central Processing Unit (CPU) can access directly - Random Access Memory (RAM), Read Only Memory (ROM) and cache memory are all primary storage.
Which forms of storage are secondary storage?
Any forms of storage that the Central Processing Unit (CPU) cannot access directly - Hard Disk Drive (HDD), Solid State Drive (SSD), USB drives, CDs, DVDs, and magnetic tape are all examples of secondary storage.
Which three technologies are used in secondary storage devices?
Optical, magnetic and solid state are the three technologies used in secondary storage devices.
Give two examples of optical secondary storage devices
Compact Discs (CDs), Digital Video Discs (DVDs), Blu-Ray discs.
Give two examples of magnetic secondary storage devices
Hard Disk Drives (HDD), magnetic tape, floppy disks (**old technology**)
Give two examples of solid state storage
USB drives (also known as USB sticks, memory sticks…), Solid State Drives (SSDs)
How does magnetic storage hold data?
Tiny magnetic particles can be aligned ‘north-south’ or ‘south-north’. Write-heads can be used to change the alignment of the particles in a certain area (set a single bit as one or zero). Read-heads can pass over the top of the particles and detect their alignment (‘read’ the bit as one or zero)
How does optical storage hold data?
The surface of an optical disc is etched with dips called ‘pits’ and the non-etched sections are called ‘lands’. Pits and lands cause a laser beam to be scattered or deflected by different amounts. Pits represent zeros and lands represent ones in binary.
Which characteristics should be considered when choosing what type of secondary storage could be used for a given scenario?
Cost, reliability, durability, portability, capacity, speed of data access
In the context of choosing secondary storage types what is cost?
The cost per unit (per CD, per USB stick etc.) of the secondary storage device
In the context of choosing secondary storage types what is reliability?
How likely the device is to continue to function as expected.
In the context of choosing secondary storage types what is durability?
How rugged or robust the device is.
In the context of choosing secondary storage types what is portability?
How compact and lightweight the device is (how easily carried).
In the context of choosing secondary storage types what is capacity?
How much data can be stored on the device
In the context of choosing secondary storage types what is speed of data access?
How fast the data held on the device can be accessed!
How is the total capacity needed on a device calculated?
Multiply the size of each file type by the number of that type of file and then add up the totals for all the different file types.
What is cloud storage?
Storage held on a computer in a remote location and accessed via the internet.
Describe the features of optical storage
-Low capacity compared to other types of storage -Slow to access data -Thin, lightweight so portable in some circumstances -Very cheap (especially to mass produce)
Give example of uses of optical storage
-CD (can be read only or read and write) -DVD (can be read only or read and write) -Blu-Ray (read and write)
Describe the features of magnetic storage
-High storage capacity -Quick to access data -Has moving parts will eventually fail
Give example of uses of magnetic storage
-Hard disk drive -tape (used for backup)
Describe the features of solid state storage
-Medium storage capacity compared to other types -Very quick to access data -No moving parts so highly reliable -Silent -Low power -Limited number of read/write cycles -Expensive compared to other types of storage
Give example of uses of solid state storage
-SSD -USB sticks -SD cards,
