RAID (Redundant Array of Inexpensive Disks) is a method whereby information is spread across several disks, using techniques such as disk striping (RAID Level 0) and disk mirroring (RAID level 1) to achieve redundancy, lower latency and/or higher bandwidth for reading and/or writing, and data recoverability.

RAID is the linking together of two hard drives, either for performance (RAID 0) or security (RAID 1). Most computer users do not need to use RAID. If you are unsure of what RAID is, have a quick read below to see if you think it will benefit you.

RAID 0: Striping

RAID level 0 refers to striping data across multiple disks without any redundant information.
Striping can be used to enhance performance in either a request rate intensive or transfer rate intensive environment. Unfortunately. striping reduces the level of data availability since a disk failure will cause the entire array to be inaccessible.

Advantages:

High performance
No cost penalty - all storage is usable

Disadvantages:

Significantly reduced data availability - all data is lost if one hard drive fails.

RAID 1: Shadowing/Mirroring/Duplexing

RAID level 1 refers to maintaining duplicate sets of all data on separate disk drives. Of the RAID levels, level 1 provides the highest data availability since two complete copies of all information are maintained. If one of your hard drives fail, you will have an exact copy of all your data on your other hard drive, meaning that you can carry on working as normal without having to restore lost files. You could see it as having a permanent automatic back-up of all your data. Even if one hard drive fails, you can then use the other hard drive to create a new RAID array and so in theory (unless you have an electrical surge, or both hard drives fail simultaneously) you can never be caught out when you turn on your computer one day to find that your hard drive has failed, because you always have a backup.

Advantages:

Excellent data availability
Higher read performance than a single disk

Disadvantages:

Expensive - requires two hard drives (if you order 2 x 160Gb, you will only have 160GB total storage space and not 320GB)

Summary

RAID 0 requires two hard drives. Data is written to both hard drives (part of the data on one hard drive, and part of the data on the other) to give faster write times and also faster read times. Hard drives act as one drive - e.g. one large 320GB hard drive consisting of 2 x 160GB hard drives. However, if one hard drive fails, the array will be broken and all data will be lost.

RAID 1 requires two hard drives. Data is written to both hard drives simultaneously (files are written in full to each hard drive) and therefore you will have an automatic back-up should your hard drive ever fail. However, this security comes at a cost - two hard drives are required and you can only fill one hard drive, (as the other will be automatically filled as you go along) but for some people the added security is well worth the extra cost.

TABLE OF CONTENTS:

• CPU Comparison: AMD Athlon or Intel Pentium? What is the difference?
• Digital TV cards and TV/Radio Tuners for Media Centre PCs
• DVI, Sound Cards, Network Cards, Wireless Adapters
• FDD, Case, Power Supply Unit
• Firewire, Monitor, Keyboard, Mouse
• Front Side Bus(FSB), Hyperthreading Technology (HT)
• Optical drives: CD, DVD, CD-RW, DVD Writers and Graphic Cards
• Hard disks: RAID Arrays and Striping
• RAM, Motherboards
• Windows Operating Systems: Comparison Tables
• Most common PC applications: Anti-virus, MS Office Suite