Computersight -

If you take a look at how fast an hard disk can access data and transfer it you will not be too much impressed when you compare it to the RAM memory or any other non disk memory. It’s not the hard disk fault, they have to spin and since they have some moving mechanical parts, they must be slow compared to anything that only has electricity moving around it.

However computer top class people came up with something that we all must consider brilliant. How about putting several hard disks working together to have better results?

RAID was born then.

RAID stands for Redundant Array of Inexpensive Disks and it’s a way to have much faster transfer times with normal hard disks that you ever could with just one. Basically you put several hard disks working together and you get the speed combination of them all. If you hard disk supports 150 MB per second of data transfer, with RAID and two hard disks you could get 300 MB per second. That’s two times more. The ratio is not a perfect double but it’s close to that. Now if you put four hard disks the transfer time will be even faster and the more disk you add, the faster the system will be.

RAID can be many things and not only hard disks working together. The RAID we saw above was the RAID 0 and the most used one. RAID 1 is making another hard disk working like if it was the mirror of the first disk. If the first disk gets damaged, the second one will be used instead of the first because it’s a perfect copy. This is the fastest backup tool available. And not the most expensive. More people do not use it because the system is not yet in the mass market nor in the mass media. You only read about it sometimes. Too bad.

There are more than 6 types of RAID. There is the RAID 0, RAID 1, RAID 2, RAID 3… and each one has it’s own unique feature. The only ones you should care about is the 0 and the 1.

RAID 0 seems to be the perfect solution for speed and storage capacity but it has some great disadvantages too:

1. It’s two times more expensive than a computer hard disk solo.
2. If one hard disk gets damage, the whole system crashes because half of the files re on each disk, one cannot live without the other.
3. This technology is not yet mastered because it’s almost not used in the personal home computing market.
4. Access time is still the same, you can have faster file transfer speed, but the time to find the right byte to be transferred is still the same.

Before you attempt to make your own RAID system please take note of the disadvantages above. Data failure is the number one reason why this system is not mass implemented yet. RAID 0 with just two disks double the chances of getting disk damage and four disks means four times more chances to get disk damage.