First 566 words of the document:
Selection and use of storage requirements, media and devices
Why is data stored?
Storage of data is an essential part of ICT. Data is likely to be used again in the future and
entering it again every time it is needed is very time-consuming.
Storage media may be used when purchasing software or when transferring data from one
computer to another. Data is also stored as a backup in case the original data is damages. For
example by hardware failure or virus
Data is also archived, this mean removing data that is not used frequently from the main
backing storage of the computer (usually a hard disk) to a medium that can be stored away
from the computer, but accessed if the data is needed.
Common storage devices:
These devices all store data for later use. When the computer is off all data that is stored in the main
memory is lost but data stored in these devices is not lost:
Magnetic Storage devices
1. Hard disk the most common storage device, sometimes called a hard disk.
Generally housed within the box containing the processor (an internal hard disk).
Internal hard disk can hold many gigabytes of data; it is used to store the operating
system as well as data files. Hard disk can be divided into folders that make it easier
for the user to store work and find work ( folders can be divided into sub folders)
2. External hard disk- increasingly common for a computer to have an external hard
disk which connects to the computer Via a USB port. Can be used as a backup in case
of internal hard disk failure. Can also be used to increase the capacity of a computer
if the internal disk is getting full. Small and relatively portable can be disconnect and
connect to a different computer. This allows it to transfer data from one computer to
3. Floppy disk- Removable 31/2 floppy disk consistence of a small, flexible plastic,
magnetic disk inside a hard plastic disk. The usefulness of the disk has decreased as
the size of files has grown. The capacity of the disk is small normally 1.44MB data
transfer is also slow. It was mainly used to keep back up of small files like text files ,
letter or small documents or for transferring small files between two or more
computers. Floppy disks are still very cheap but flash memory has become and more
convenient way of storing files or taking them to another computer
4. Magnetic tape- is used for backing up entire networks due to their high capacity
(e.g. 120 GB). It's a serial medium this means that the data has to be read in the order
it is taped. It is sometimes used for archiving large volumes of data.
1. CD-ROMS (Compact Disk-Read -Only Memory) small plastic optical disks. Like
floppy disk they can also be moved from computer to computer. Store large
quantities of data (650 MB or 0.65 GB) permanently. Data on this device is less
prone to damage than on a floppy disk as the data-storage method uses laser
rather than magnetic technology. Data can be read but not written. Commercial
Other pages in this set
Here's a taster:
CD-ROM & many computing magazines are sold with
CD-ROM that hold free sample software.
2. CD-RS (Compact Disk-Recordable) - are written compact disks. Using a special
writable CD drive, up to 650 MB of data can be recorded onto a blank disk. This data
cannot be altered but it can be read by another PC with a slandered CD-ROM drive,
this mean CD-RS is suitable for achieving data that can be removed from the
computer's hard drive, but is available when needed.…read more