This preview shows page 1. Sign up to view the full content.
Unformatted text preview: t is accented by all CD-ROM
We saw that CD-ROM disks are produced by manufacturers with expensive duplication
equipment This is economical only when a large number of copies of a master disk are
to be produced. Often users of computer systems would like to produce a few copies, or
a single copy of their own information in-house. This is possible by the use of WORM
WORM stands for write-once, read-many. WORM disks allow the users to create their
own CD-ROM disks by using a CD-recordable (CD-R) drive, which can be attached to a
computer as a regular peripheral device. WORM disks, which look like standard CDROM disks, are purchased blank and encoded using a CD-R drive. The information
recorded on a WORM disk by a CD-R drive can be read by any ordinary CD-ROM drive.
As the name implies, data can be written only once on a WORM disk, but can be read
many times. That is, as with a CD-ROM disk, once data have been etched on to the
surface of a WORM disk, they become permanent that can be read but never altered.
Moreover, writing on a WORM disk cannot be done in multiple sessions, and all the data
to be recorded have to be written on the disk surface in a single recording session. The
same laser beam technology as discussed before is used for recording and reading of data.
Because of their permanent recording nature and large storage capacity, WORM disks are
the preferred storage media for archival application, which now depend on microfilm,
magnetic, or paper file media. Data archiving enables old data to be recorded on a
secondary storage media (such as a WORM disk) so that they can be deleted from the online storage device (such as a hard disk), thus freeing space for new data. WORM disks
are also an ideal medium for making a permanent record of data. For example, many
banks use them for storing their daily transactions. The transactions are written to a
WORM disk in-house by the bank and become a permanent record that can be only read
but never altered.
Advantages and Limitatio...
View Full Document
- Spring '14