Microsoft Windows Home Server is the answer to a couple of questions -- one of them yours, and one of them Microsoft's.

The Windows Home Server Console shows what's been backed up.
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The question for you is, do you have a home network that connects several PCs, but no backups of all the important data on those PCs? The odds are you do. If so, Windows Home Server may be just the solution you need. This extremely smart server application will back up all those PCs as safely as you want, provide easy access to the files you want to share on your network (like music and media files), and even give you remote access to your files and computers across the Internet.

That may all sound too good to be true, but believe it. Windows Home Server is a great application. It does have what you might consider a downside: you have to dedicate a PC to running it. But while you might think of laying out for another computer as a problem, to Microsoft that's an opportunity. In fact, Microsoft thinks there are perhaps as many as 40 million people just like you out there, which is its estimate of the market for its Window Home Server product.

And that's what makes it the answer to Microsoft's question. The company sells 90%-plus of all the operating system software in the world. Its potential growth is tied to the growth of PC hardware. So how does it sell you another PC -- not a replacement, but an additional computer? Same answer: Windows Home Server.

The 40 million number was cited by Steven VanRoekel, director of product planning for Microsoft's server solutions, in an interview during last spring's Windows Hardware Engineering Conference, where Bill Gates' keynote featured -- that's right -- Windows Home Server.

VanRoekel's planning is clearly aimed at putting computers -- and, coincidently, Microsoft OS software -- into the home, the same way DOS and Windows did: by building an ecosystem of OS, compatible hardware, and third-party application software. That ecosystem plan seems to be on target: by year's end there will be several models of Home Server appliances on the market, and there's a growing after-market of third-party software products and plug-ins.

But Windows Home Server is also available in an OEM edition for system builders that is perfect for do-it-yourselfers, as well. It's affordable -- you can buy it online for about $170. It has very modest hardware requirements. And while the installation isn't exactly hands-off, if you can install a hard disk, there's no reason you couldn't build your own Home Server.

You can see each backup's time, size, and status, including problems like this one, caused by corrupted data on the drive.
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Home Server does several things, but it's first and foremost a backup solution: installed on a home network, it can automatically back up all the hard disks on networked PCs running Windows. Through its console you can manage the backups, recover individual files in their current or previous versions, and manage users and their access to a set of shared folders that are also stored on the server.

Backing up, like flossing, is something everybody knows they should do more of, but most people don't do enough of. Mostly that's because backup is tedious, and backup solutions have historically been lame.

Backup has two goals, and most backup software has just enough smarts to know about one of them. Some backup packages copy everything: they do a full backup. Some even save an image of your drive. Other backup applications do incremental backups -- they save the files that changed today, and the files that changed yesterday, and the files that changed the days before that.

Incremental backup is good if you want to recover a file you saved last week and then unfortunately overwrote, but it's not very good for recovering an entire disk after a disaster. Full backup, conversely, is great for brute-force copy-it-all, but not good for file-at-a-time.