Dear PropellerHeads: I was customizing a new computer on the Web the other day and they had hard disks with RAID. Is that worth getting?

A: Almost definitely. I myself have a RAID system at home and will never buy another computer without it. I am that satisfied.

RAID, short for Redundant Array of Independent Disks, is a system of multiple hard disks that provides increased speed or redundancy (or both) over a single hard disk.

Historically, RAID has been reserved for servers, but more and more we are seeing them in desktops as hard drive prices continue to plummet. I'm now seeing 2TB (that's 2000 GB) drives going for under $100. That's just plain criminal. I remember putting down that kind of coin for only 100MB!

You probably saw two different RAID configurations available: RAID 0 and RAID 1. What's the difference?

RAID 0 improves speed by putting different parts of a file onto different disks. This concept is called striping. If you have a RAID system with two hard drives, it should read and write files just about twice as fast as a single drive. If you don't think that is significant, just imagine if you could cut your commute time in half!

The hard disk is probably the slowest thing in your computer. So making that bottleneck twice as fast is going to have a noticeable effect.

RAID 1 essentially makes a copy of everything you save to your hard disk to another disk. The actual word we PropellerHeads prefer is mirroring, as one disk is the mirror image of the other. This arrangement is the ultimate in reliability because if your main hard disk fails for any reason, the spare automatically steps in to save the day.

RAID also comes in more elaborate configurations that mix these two basic forms. However, these are still pretty much only suitable for servers as they require more hard disks than can probably fit into your computer.

So, which of the two RAID setups is best for you? I'll answer that question with a question: How good are you about backing up your data?

If you are the Homer Simpson of the computing world, do yourself a favor and get a RAID 1 configuration. Although it is not the ideal backup system, it is a lot better than nothing. And not having to remember to do backups will be a huge benefit for you.

But if you are like me and want your computer to cruise along faster

see RAID, C6

from C5

than anybody else's, get RAID 0. The downside of twice the speed is that you also have double the chance of a hard drive failure. A RAID 0 system is entirely knocked out if any one of its hard disks fail. However, as you religiously back up your data, you can sleep easy. Well, at least I can sleep easy.

Unfortunately, not all computer manufacturers are playing fair when it comes to offering RAID systems. HP only charges you $10 more for two 1TB drives instead of a single 2TB drive. At the other end of the spectrum is Dell. They'll scorch you an extra $200 for two 750GB drives in place of a single 1.5TB drive. R u serious?! Most other vendors fall between these extremes.

So the question "is it worth it" may depend upon which manufacturer you get your computer from. But in general, regardless if your goal is speed or redundancy, it is well worth the little extra you have to pay to get it.

When the PropellerHeads at Data Directions aren't busy with their IT projects, they love to answer questions on business or consumer technology. Email them to questions@askthepropellerheads.com or contact us at Data Directions Inc., 8510 Bell Creek Road, Mechanicsville, VA 23116. Visit our website at www.askthepropellerheads.com.