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level: Secondary storage (NEED)

Questions and Answers List

level questions: Secondary storage (NEED)

QuestionAnswer
· Explain the need for secondary storage within a computer systemMain memory is volatile and is lost without a power supply
Rank an SSD, HDD, and an optical disk for typical capacity Include valuesHDD: High, 500GB to 5000GB SSD: Relativly low, under 1000GB Optical disk: Very low, highest is about 25GB
Rank an SSD, HDD, and an optical disk for read write speeds Include values Include reasons whySSD: Very high, around 500MB/s, has no moving parts HDD: Good speed, about 100MB/s, has some moving parts Optical disk: Relavitvly low, around 30MB/s, comprised of one main moving part
Rank an SSD, HDD, and an optical disk for power consumptionHDD: High Optical disk: High SSD: Low
How does an optical disk operate?o Uses a laser, guided by a lens, to read and write o A rotational mechanism will spin the disk o To write power lens engravees disk with pits and labds correspinding to 1s and 0s o Reading: Done by photodiodes detect the light reflected from the disk by a less powerful lens, this will be different due to the grooves reflecting light differently, and interpret this as 1s or 0s
In a HDD what is a block addressAddress of a block
What is the commonest form of read write secondary storageMagnetic disk drive AKA HDD
Whats another name for a magnetic disk driveHDD
What are the parts of a HDD ??? o Platter rotation o Read/write head o Actuating arm o Spindle o Motor o Platter Correct: Circular platter Read/write head Actuating arm
In a HDD what is trackOne of the rings on a platter of a hard disk
In a HDD what is a sectorSubdivision of a track
In a HDD what is a blockWhole sector of track
Name ways in which HHDs can be kept the same size but their capacity increasedAdding more platters Decreasing the width of tracks
State the principles of operation for HDDso Theres a number of circular platters which are made from magnetic material, above each is an arm which is a read/ write head o Read/write head changes the polarity of parts of the platter o The actuating arm allows the read/write head to access all portions of the platter o Data is written into sectors
What is seek timetime to move the read/write head to the track
What is latency in the context of a HDDtime to rotate the actuating arm to the sector
How does an SSD work?o SSD is formed of multiple blocks o These blocks are formed of lots of pages o These consist of memory cells which are formed of floating gate transistors which store information by trapping electrical charge o The writing of information is dictated by the controller
Rank an SSD, HDD, and an optical disk for latencyHDD: High SSD: very low Optical disk: High
Rank an SSD, HDD, and an optical disk for portability Include an explanationHDD: Bad, bulky and heavy and easily damaged by movement SSD: Good, lightweight and rarly damaged by movement Optical disk: Okay, small and lightweight but can be damaged by scratches and dirt
Give some examples of what each secondary storage could be suitable forHDD: Desktops, PCs, and servers SSD: Laptops, tablets and phones Optical disk: Sharing and distributing small volumes of data
Explain how information is recorded and read from a CD-ROMs
Define an optical deviceUse of a laser light to read from or write data to an optical disk
What are the parts of an optical deviceo Laser o Lens o Photodiodes o Rotational mechanism
Describe the pattern in which inforamtion is stored on an optical device and explain why it is done like thisIn a spiral from the centre So that users can directly access the files they’re interested in, without having to open any others.
Picture an SSD...
Labeled HDD.
Picture an optical drive.
Give the components of an SSDNAND (flash) memory Floating gate transistor Controller
For an optical disk: 1. What are the engraved parts of a disk 2. What are the non engraved parts of the diskPits Lands