Practical Technology

It’s not especially easy to deploy, but Windows 7 supports simple software RAID. Here’s how to do it, using low-cost storage you already own: a bunch of USB flash drives. (I’d say I created a RAID array of USB drives simply to demonstrate the technique, but really… one reason to do this is because, well, I could. We techies can be so easily amused.)

There’s no such thing as enough disk room or a safe-enough hard drive. The moment you think you have enough hard disk space, you find yourself collecting high-definition videos or your hard disk starts whining and clicking. One solution to both problems is to use an ancient computing technique that dates back to when a big hard drive was 5 MBs and came in a casing as large as a washing machine: redundant arrays of inexpensive disks (RAID).

RAID has several benefits. The first is that RAID has the potential to deliver vastly increased data transfer rates. In theory, the input/output transmission rate of a RAID system can be more than ten times greater than a ordinary hard drive.

RAID pulls this trick off by “striping” data across the array’s disks. In English, this means that a file can be distributed across the array so that it can be read or written much more quickly. For example, With RAID, the system will place a file on the media so that while the first part of the file is being read from disk on one array, the second portion is already being picked up from disk two.

By enabling parallel data transfers, data throughput can be multiplied by the number of drives in the array. For example, a four disk RAID could have four times the throughput of an equal-sized single drive. A RAID that’s designed for speed and nothing but speed is called RAID Level 0.

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