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Unformatted text preview: d out as a standard interface for connecting devices to
small computer systems. But the advantages of a common interface soon became
apparent in all sizes of systems, and newer versions of SCSI have much higher datatransfer rates and are used in high-end systems.
What is Data Backup?
Data backup is the process of creating a copy of the data from an on-line storage device
to a secondary storage backup device such as, magnetic tape, floppy disk, zip disk, disk
pack or WORM disk, (not necessarily but usually for off-line storage of the data) so that
if by accident the data on the on-line storage device gets corrupted or lost, it can be
retrieved from the backup device and stored back on the on-line storage device.
Why Backup Data?
Taking periodic backup of on-line data and keeping them on off-line secondary storage
devices is an important and necessary practice for computer users because the data on an
on-line storage device, such as a hard disk, can be damaged or lost in any one or more of
the following ways:
1. A disk crash.
2. A virus attack.
3. A hardware malfunction.
4. An unintended accidental deletion of useful files.
5. A natural disaster like fire or earthquake damaging the computer system.
The amount of time it would take you to re-create all of your files if you lost them is far
greater than the few minutes it will take you to back them up. Hence protecting valuable
data with regular backups is a must for all computer centres and all computer users.
Types of Backup The two basic types of backup are full backup and incremental backup. They are
1. Full Backup. In this case, all the data on the on-line secondary storage device is
copied on the backup device at the time of backup. That is, the backup procedure creates
a copy of every file from the on-line secondary storage device on to the backup device,
whether the file has been changed or not. Depending on the volume of data being backed
up and the backup device used, full backups can take anywhere from a few minutes to a
few hours to complete.
2. Incremental Backup. Sin...
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This document was uploaded on 04/07/2014.
- Spring '14