what is RAID or RAID controler in computers?

Question

Is it for hard disk mirroring ? is it a software ?

Answer 1

Redundant Array of Independent Drives is also known as Redundant Array of Inexpensive Drives (or Disks), and in either respect it is referred to as RAID. RAID is an umbrella term for computer data storage schemes that divide and replicate data among multiple hard disk drives. RAID's various designs balance or accentuate two key design goals: increased data reliability and increased I/O (input/output) performance......
http://en.wikipedia.org/wiki/RAID
this iste has some good working examples of it, it confused the hell out of me when i was looking at it first but examples helped.
http://www.acnc.com/04_01_00.html

Answer 2

This question can have a really long answer, so I will try to summarize it as best as I can.

RAID is a collection of hard drives working together as one in various configurations. Typically RAID is referred to as a "Redundant Array of Inexpensive Disks", and therefore some people do not consider hard drives arranged in a non redundant form, RAID.

There are various configurations of RAID, one of which is basic mirroring of data from one hard drive to the other.

If you are interested in all the different RAIDs out there, you can check this link out:
http://www.acnc.com/raid.html

It provides you with nice descriptions and moving diagrams of how each RAID works. The most popular RAID configurations are : 0, 1, 5, and 10.

There are different types of controllers, some say they are RAID controllers, but actually they are more like normal controllers with drivers that do the raid in software. Typically the cheaper controllers are software based, the hardware based ones typically go for a few hundred dollars and up.

The hardware based controllers do the raiding on the card, and reduce the work the CPU would of had to do if it was a software based. These controllers are usually quite compatible with most operating systems as it shows the raid arrays as just a normal hard drive.

Now, if you just want raid, you can do it without any raid card through the operating system/software. I know for a fact that windows can raid on it's own.

Answer 3

RAID stands for 'Redundant Array of Inexpensive Disks'

There are two kinds of RAID (1 and 0).

I can't remember off the top of my head which is which, but basically you can have up to four hard drives in a computer, and you can set them to mirror for data protection - or for speed.

It requires a RAID controller card, and software to manipulate it (usually comes with the card).

Answer 4

RAID is used in servers and similar computers where data protection is essential. There is more than one type of RAID (RAID0 thru RAID5) which offer different levels of protection.

But all involve some type of "disk mirroring". The simplest (RAID0) uses two hard drives and keeps them both identical so that if one fails, you can switch to the other with no loss of data. The most complex (RAID5) uses multiple hard drive, and has a hash code saved on the drive before and after each drive so that if one fails, the code can be used to recreate the failed drive.

There are software packs that will let you implement RAID0 (disk mirroring) on a PC with no special hardware. But for any of the others (and it is recommended for RAID0) you have to have special hardware also.

Answer 5

RAID stands for "Redundant Array of Independent Drives" and is sometimes also referred to as "Redundant Array of Inexpensive Drives". There are several different types all of which come with different limitations and options.

RAID capabilities allow the operating system to take any number of different drives of the same size and show them (and use them) as one drive. Software and Hardware options for setting up a RAID controller both exist, and are implemented differently for the different options.

There are three key concepts in RAID: mirroring, the copying of data to more than one disk; striping, the splitting of data across more than one disk; and error correction, where redundant data is stored to allow problems to be detected and possibly fixed (known as fault tolerance). Different RAID levels use one or more of these techniques, depending on the system requirements.

You normally see RAID used on servers but you can also use them on workstations, as of Windows 2000.

Answer 6

It synchronizes two exact matching hard-drives together to increase access speeds. It's a hardware configuration that is controlled by software (RAID drivers).

Answer 7

redundant array of inexpensive disks