- Deletes any data already on the disk
- Divides the disk into the tracks and sectors – one sector holds 512 bytes of data.
- Set a root directory which lists the files on the disk and which sectors the data for each file is kept in.
- Finds any bad or damaged sectors on the disk that cannot be used.
Hard Disks
The hard disks used with PC’s consist of one more disk platters permanently sealed inside a casing. Hard disks typically have a capacity of between 10Gb and 30Gb. (1Gb = 1,000Mb).
CD-ROM
Compact disk only read memory drives are now supplied with most PC systems. Up to 650Mb of data can be stored in these disks. CD-ROMs use a laser beam to read the data from the rotating disk surface. The light reflected back is interpreted as data.
Writeable CDs
Writeable CDs are now available in two different formats – CD-R (CD Recordable) and CD-RW (CD-Rewritable). Recordable CDs and only be written on once whereas Writeable CDs can be written on many times. They are useful backup devices.
DVD
DVD-ROMs are becoming more popular than video types. They have more advantages than the CD-ROM.
- They are much faster
- They have a much higher capacity
- They can also play standard CD-ROMs and audio CDs
- They can hold up to 135 minutes of high quality video and CD quality sound.
Zip Disks
Zip disks are quite cheap (under £10) and more reliable than a floppy disk. The older types hold 100Mb of data whereas the newer ones hold 250Mb.
A zip drive is often an option on a Pc, together with a CD-ROM or DVD drive and a floppy drive. Or you can by any of these externally. They are faster than floppy disks; they are still much slower than hard disks.
Jaz Disks
Jaz disks are bigger versions of Zip disks. They hold 1Gb of data, and like zip disks, can be used on PC’s and macs. Because they hold so much data, they are ideal for multimedia applications, where graphics, animations, video and sound are used.
DAT (Digital Audio Tape)
DAT is used almost exclusively for backups and for archiving old data that needs to be kept but which will probably never be used.
Look at to find out more information about storage devices, arrange the following storage media:
- In order of speed starting with the fastest.
- In order of storage capacity starting with the largest.
a.
- Hard disk
- DVD
- CD-ROM
- Jaz disk
- Zip Disk
- Floppy disk
b.
- Hard disks
- DVD
- Jaz disks
- CR-ROM
- Zip disks
- Floppy Disks