secondary storage Flashcards
what are the three types of secondary storage?
magnetic, solid state and optical
what is secondary storage?
it is a non-volatile long term storage of data, files, software- where data is stored when not in use
why do we need secondary storage?
- to access it again later
- use software
- interact with the computer
what would happen without secondary storage?
- software would need to be installed each time it is used
- couldn’t save any files or data
characteristics of secondary storage?
- capacity (how much data able to store)
- speed (how fast data is accessed)
- portability (how easy can move from one place to another)
- durability (how well does it last)
- reliability (is performance consistent)
- cost (how much does it cost per kb, mb..)
magnetic examples:
- hard disk drive
- floppy disk
- tape drive
optical examples:
- CD
- DVD
- Blue Ray
solid state examples:
- SD card
- USB drive
- SSD (solid state drive)
description of magnetic storage
a read/write heads move across a platter and they change how magnetised that part of the medium is. The platter consists of data tracks and sectors.
how fast does a magnetic storage platter spin?
between 5400-15000 rpm
magnetic characteristics
- not durable
- reliable
- good capacity
- cheap
solid state description
similar to ROM, however it also allows us to write to it (EEPROM)- this is made of transistors (switches)- state of the switches determine if it is on or off (I/O) is stored
- it is not volatile
solid state characteristics
- portable
- good capacity
- good speed
- expensive
optical description
a laser light creates marks in a pattern on the disk ( these marks are called ‘pits’ or ‘lands’) - a laser light detects where the marks are and translates this into a readable format
optical capacity
700MB- 25GB
