Tape
Magnetic tape data storage, more commonly known as
tape, has been around since the early days of computer
systems. Magnetic tape for data storage was initially wound
on 10.5-inch (27 cm) reels, and tape cartridges and cassettes were available for smaller computer systems as early
as the mid-1970s.
A tape drive provides sequential access storage, unlike a
disk drive, which provides random access storage. A disk
drive can move to any position on the disk in a few milliseconds, but a tape drive must physically wind tape between
reels to read any one particular piece of data. Coupled with
the fact that the costs of disk storage have decreased much
faster than that of tape storage, it means that tape has
fallen out of favour as a data storage mechanism.
the reflected beam’s
phase is shifted in
relation to the incoming beam, causing
destructive interference and reducing
the reflected beam’s
intensity.
This pattern of
changing intensity of
the reflected beam
is converted into
binary data. DVDs
use light of 650 nm
wavelength (red),
as opposed to 780
nm (far-red, commonly called infrared) for CD. The