5.3.1 Other storage media
Points: (Full course)
|Candidates are expected to be able
- identify a range of storage devices
or media additional to those listed in
5.1.3 i.e. DVD, CD-R, CD-RW
and Zip drives;
- describe situations when each of the
devices/media above may be used;
- describe the comparative advantages
and disadvantages of using storage media identified above and
Magnetic Storage media:
Jaz drives are similar
to floppy drives because the individual disks are removable and portable but they
hold much larger amounts of data (typically between 100 MB and 2 GB).
- Advantages: Portable media, relatively cheap, good for archiving
- Disadvantages: Not a compact as USB flash-drives, can be damaged,
slow data transfer compared to modern alternatives.
Other Optical Storage media:
Digital Versatile/Video Disc
- DVD drives
are now replacing CD drives in computers due to the huge memory capacity of the disk and the high quality of
stored images. A DVD single sided, single layer DVD can store up to
4.7 GB of
data, the equivalent of 26 CD-ROMS. This means full-motion
films with sound tracks and subtitles in multiple languages can easily be stored on one
- Advantages: a film stored on a DVD has significant advantages over magnetic VHS
video tape because the digital images and sound tracks are of a
higher quality and do not deteriorate with constant use. The user can also move to any part of the film
immediately (random access). DVD-RW drives (writable drives) are
relatively cheap now and will soon replace VHS tapes as a way of recording films.
- Disadvantages: easily damaged by being scratched.
Recordable Compact Disk media
- CD-R - these CDs are initially blank
but you can use a special read/write CD drive unit to store programs and data onto the
disc but they can only be
written to once.
- Advantages: Very cheap way to store data. Not damaged by
magnetic fields or water.
- Disadvantages: The data cannot be edited once it has been
written to the CD-R. Easily damaged by being scratched.
- CD-RW - these are similar to the ‘R’ type above but
read, write and delete files from the disc many times, just like a hard disk.
- Advantages: As for CD-R plus the ability to re-write and erase
data so they can be used again.
- Disadvantages: Easily damaged by being scratched.
- Both CD-ROMs and CD-Rs can be referred to as WORM devices. This stands for
Write Once Read Many times.
1 CD-ROM (650 MB) = 451 Floppy
disks (1.44 MB)
1 DVD (4.7 GB) = 7
Other ways data can be stored:
Magnetic strips - a strip of magnetic tape built into a plastic cards
can store a small amount of data. Phone cards, debit cards and library cards can be written
to so changes in the data can be stored.
Smart cards - a processing microchip built into a plastic card can
store data as well as processing information. The SIM card used in a
mobile phone stores phone numbers and names as well as allowing providing a menu of
options and allowing you to connect to your service provider.
cards - there are used in a wide range of applications to store data.
Typical examples include Compact FlashTM and
SmartmediaTM memory cards which are used in
digital cameras. They can have capacities of over 1 GB and a memory card
reader or floppy disk adapter can be used to transfer the data to a computer.
(Read Only Memory)
- chips are used to store the permanent
operating system data (the BIOS). In some types of computer, such
as a pocket book, they may be used to store major programs such
as a word processor. They are however more difficult to replace
when a new version is released. They are also used to store the
permanent programming inside a domestic device such as a
television or washing machine.