2. DEFINITION OF STORAGE DEVICES
• A storage device is any type of computing hardware that is used for storing, porting
or extracting data files and objects. storage can store or hold information both
temporarily and permanently. They may be internal or external to a computer, server
or computing device in general.
3. MAGNETIC MEDIA AND MAGNETIC
STORAGE DEVICES
• Magnetic storage is one of the most affordable ways to store large amounts of data.
Magnetic storage uses the two types of magnetic polarities to represent the binary
information consisting of 1s and 0s. Commonly used devices that use magnetic storage
include
• - magnetic tape
• -floppy disks
• - hard disc drives
4. MAGNETIC TAPE
• It is one of the oldest forms of computer data storage.
• It is a thin strip of magnetic coated plastic which is wrapped onto a
reel.
• Data is stored on the magnetic tape in form of 1s and 0s which are
binary numbers.
• Data is written to read in sequence which is also called serial access.
• This type of media has very slow data access rate. because it is so slow
it is useless for real-time applications that is where data being stored is
constantly being updated.
5. USES OF MAGNETIC TAPE
• Used where large amounts of data need to be backed up.
• Used where speed of reading or writing data is not a priority. For
example, it is used to hold data in batch processing applications
such as clearing bank cheques and producing payslips. It is used
here because speed is not important.
• It is used for backups of computer networks in schools and
businesses.
6. ADVANTAGES AND DISADVANTAGES OF
MAGNETIC TAPE
advantages
• Less expensive than a hard disc
drive which is of equivalent
capacity.
• Very robust.
• Very large storage capacities
disadvantages
• Very slow access and transfer
of data
• Needs another tape to update
data
7. FLOPPY DISCS
• This is also an old method of data storage where data is stored on a thin plastic disc.
• Data on a floppy disk is read or written by a floppy disk drive which rotates the disk.
• As the disk rotates, a read or write head is used to add or read data. This is done using direct
access methods. Even though they use direct data access, their data transfer rates are very
slow.
• The disk of the plastic is protected by a retractable metal sleeve and a hard plastic casing. A
small notch provides write protection.
• Maximum storage on a floppy disk is about 1.44 MB which is about 700 pages or writing.
they do not have the capacity to store large modern files therefore making them useless and
computers no longer have floppy disk drives installed in them.
8. USES OF FLOPPY DISKS
• They can be used where very small files need to be
transferred for example small word processing
documents.
9. ADVANTAGES AND
DISADVANTAGES
advantages
• Very cheap to buy
• Can be write protected easily
which protects against
accidentally copying over files.
• They are easily portable
disadvantages
• Very low storage capacity
compared to other media
• Very few modern computers
have floppy disks.
• Not robust
• Slow data transfer rate.
10. HARD-DISK DRIVE
•We have two types of hard disk drive that is :
•Portable
•Fixed hard disk drive
11. FIXED HARD DISK DRIVES
• They are used on all computers and are the main method of storing data. They are
capable of very fast direct access of files and have very large storage capacity.
• The disc surface Is coated with magnetic film which is where data is stored.
• They have read or write heads which allow data to be written or read from the disk.
• Hard disks are used to store operating systems, software applications and all other
files.
• Typical storage space is 250 GB to 4 terabytes
12. USES OF FIXED HARD DISC DRIVES
• Used to store the operating system and application software
• Used for storing files and documents.
• Real time systems and online systems use hard disc drives to store data
• Used in file servers on computer networks to store files.
13. ADVANTAGES AND
DISADVANTAGES
advantages
• Saves data to disc and reads back
from it quickly.
• Huge capacities.
• Very easy to update and delete files
disadvantages
• Can be damaged easily when
computer is not shut down properly.
• Not portable as they are meant to be
in the computer and not removed
14. PORTABLE HARD
DISC DRIVE
• They are used to store large files, same
as a fixed hard disc drive.
• They can be used as portable backup
systems.
• They are used to transfer data, files
and software between computers.
They work in a similar way to
fixed hard disc drives but are
connected to the computer
externally.
They use direct data access
methods which makes
reading and writing of data
very fast.
They are designed to be
portable.
They come with protective
casing since they are not
15. ADVANTAGES AND
DISADVANTAGES
advantages
• Fast read and write times.
• Huge capacities.
• Small and light which makes them very
portable.
• Can plug into almost any computer
disadvantages
• Easy to misplace due to their small size.
• More expensive than other forms of
storage.
• If the device is dropped, it can still be
damaged.
16. OPTICAL STORAGE DEVICES
• Optical media is all media that uses light source to read or write data onto a disc.
• It stores data on a disc as a number of data dots that can be read using lights.
• Each dot represents 1s and 0s.
• Data is read by shining the laser beam onto the surface of the disc.
• Some optical discs allow users to read as well as write data to the disc.
• This works by using a laser beam to burn the dots onto the surface of the disc and then
reading them again.
