Auxiliary
Memory : The most common auxiliary memory devices
used in computer systems are magnetic disks and magnetic ‘tapes. Other
components used, but not as frequently, are magnetic drums, magnetic bubble
memory, and optical disks. Auxiliary memory devices must have a knowledge of
magnetic, jctranics
and electro mechanical systems There are followmg auxiliary memories.
Magnetic Disk: A magnetic
.Disk is a circular plate constructed of metal or plastic coated with
magnetized material. Both sides of the disk are used and several disks may be
stacked on one spindle with read/write heads available on each surface. Bits
are stored in magnetised surface in spots along concentric circles called
tracks. Tracks are commonly divided into sections called sectors. Disk that are
permanently attached and cannot removed by occasional user are called Hard
disk. A disk drive with removable disks are called a floppy disks.
Magnetic tapes: A magnetic
tape transport consists of electric, mechanical and electronic components to
provide the parts and control mechanism for a magnetic tape unit. The tape
itself is a strip of plastic coated with a magnetic recording medium. Bits are
recorded as magnetic spots on tape along several tracks. Seven or Nine bits are
recorded to form a character together with a parity bit R/W heads are mounted
one”in each track so that data can be recorded and read as a sequence of
characters.
Internal Hard Disk Drive
o
Internal
hard disk drive is the main auxiliary storage device that stores all of your data
magnetically, including operating system files and folders, documents, music
and video. You can think of the hard disc drive as a stack of disks mounted one
on top of the other and placed in a sturdy case. They spin at high speeds to
provide easy and fast access to stored data anywhere on a disk.
External Hard Disk Drive
o
External
hard disk drives are used when the internal drive does not have any free space
and you need to store more data. In addition, it is recommended that you always
back up all of your data and the external hard drives become very useful as
they can safely store large amounts of information. They can be connected by
either USB or Firewire connection to a computer and can even be connected with
each other in case you need several additional hard drives at the same time.
