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hardware breaks down another part can assume it tasks. Enterprises often

include the legacy information systems. Legacy information systems are

those which have existed for long time, and enterprise is heavily

dependent on them. Replacing legacy systems with new ones has always

been a challenge for enterprise.

To meet their large-scale needs, enterprises use a variety of

hardware types e.g. Redundant Array of Inexpensive Disks (RAID),

Network Attached Storage (NAS), Storage Area Networks (SAN),

Enterprises Storage Systems (ESS), Blade servers, thin clients, etc.

REDUNDANT ARRAY OF INEXPENSIVE DISKS (RAID)

RAID is a group of two or more integrated hard disks. In this hard

disk system, several small disks are connected to form a single large hard

disk. RAID is more expensive for large computer but is more reliable than

traditional hard disks. RAID duplicates data, instructions and information

to improve data reliability. RAID implements this duplication on different

levels. Following is common RAID levels.

RAID 0: Splits data evenly across two or more disks.

RAID 1: Also called Mirroring. Creates an exact copy (or mirror)

of a set of data on two or more disks.

RAID 5: Use stripping technique (data, instructions, and

information split across disks in the array)

Note that these levels are not hierarchal and therefore a higher level

of RAID is not necessarily better than lower RAID level.

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