My cousin Steven Cristol should enter the lottery: he's already beaten seemingly impossible odds by enduring "seven mechanical hard drive failures in five computers," as he describes it.
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E.R. for Hard Drives (July 14, 2005)
One drive failure is unsurprising, but usually after several years of use. Two failures are improbable. Seven puts us into an episode of "The Twilight Zone."
Each brand-name drive failure set him back hours or weeks in his consulting work. His file backups were partial and infrequent.
An electrician could not help him. Banning the house cleaner from his home office - he found she was smashing her vacuum into his running computers - had no effect. The family suggested séances.
His woes ended three years ago with the installation of a belt-and-suspenders data backup system. Every bit written to his main drive is simultaneously copied, or mirrored, to a backup drive. He also regularly copies files to a magnetic tape system.
Creating perfect duplicates of his data allowed my cousin the peace of mind to know that even in a catastrophic failure, he could turn to the mirrored drive or critical files on it and be back to work in minutes.
Ever-increasing quantities of private and family data are kept on home computers. But until the last two years, there was a gap between the ever larger hard-disk drives that came with home computers and affordable methods to archive the gigabytes of documents, e-mail messages, home movies and MP3's. That gap has closed as consumer backup software has added features to write archives directly to external hard drives and higher-capacity DVD burners.
Which Files?
All mainstream operating systems comprise a mix of kinds of files. Some are needed by the system itself to manage its hardware and software tasks. Others are programs and their help files and plug-ins, documents you create with those programs and settings for how those programs work. Documents can vary greatly in size from a 500-byte e-mail message to a 10-gigabyte movie you transferred from a digital camcorder.
The most comprehensive way to duplicate a computer's data is to use software that can handle every kind of file, and store the state of those systems as a snapshot in time.
This is a trickier task than it sounds, as some files are hidden or have odd properties. Just dragging a hard-disk icon on the desktop onto a similar hard drive's icon won't work because of these arcane files and obscure aspects of how a hard disk and an operating system talk to each other. (Mac OS, up to version 9, had the unique ability to just copy a drive; it was lost with Apple's switch to Unix underpinnings.)
Picking and choosing which files to back up, like manually copying your document folder to a CD or DVD, allows you to preserve your most critical files - like spreadsheets, photos and word-processing documents.
If you use the pick-and-choose method and suffer a complete drive failure, you would have to reinstall your operating system and any applications you had separately installed, as well as all upgrades released since the time you purchased the system and software.
Which Hardware?
For businesses, streaming magnetic digital tape ruled the backup roost through the 1990's, while consumers were stuck with slow and occasionally unreliable diskettes and, later, Zip and Jaz cartridges.
Tape drives are expensive, and tapes run from start to finish: special software is necessary to fast-forward through up to 750 feet of tape to reach a particular file. A modern tape drive with the capacity of a home hard drive can cost several hundred dollars. Tapes that hold 25 to 100 gigabytes of data cost $25 to $50 each.
That's why external hard drives have emerged as the backup medium of choice: their current low price, high speed and high capacity pairs them neatly with a computer's internal hard drive.
Many users now purchase drives much larger than their internal disk in order to create cumulative archives of files as they change. Backup software creates snapshots so you can choose which version of a file to retrieve, or retrieve the entire data state of your computer at a given point in time.
A 200-gigabyte drive for Mac or Windows is $199 from LaCie USA (www.lacie.com); a terabyte drive (approximately a trillion bytes, or 1,000 gigabytes) costs $949.
Both CD and DVD burners are reliable and cost-effective choices for backup, with blank media costs plummeting. A CD burner can write about 700 megabytes to a single disc. DVD burners can put about 5 gigabytes on one disk, but newer dual-layer recorders can write up to 9 gigabytes. An external dual-layer DVD burner is as little as $119 from LaCie.
Some companies offer even simpler hard-drive backups, bundling software and hardware into a single one-button backup option. Install the software, attach the drive and hit a button on devices from Mirra, Seagate, Maxtor and others, and a backup is made with no intervention.
Software Options
The way to good data hygiene is to establish a routine and stick to it. Backup software makes it possible to schedule your archives - preferably at a time you are not also trying to use the computer.
Consumer backup software can write to hard drives and optical media, and often to any kind of media that can be mounted on the desktop.
Software from Microsoft (included in Windows XP) and Apple (included for .Mac online service subscribers) backs up and restores files on a schedule. More sophisticated software from EMC Dantz (Retrospect Desktop, $129, www.dantz.com) and Symantec's Norton division (Norton Ghost, $69.95, www.symantec.com/sabu/ghost/ghost_personal) offers full disk backup and restore; both packages include CD's that can be used to start up a computer with a failed operating system but a working hard drive to restore from a backup.
The best packages allow you to archive files as well as back them up; that is, to store multiple versions of the same file over time as it changes. But you can choose to store only the latest version of each file, too.
Restoring Data
There's often a paradox to restoring data: you need the backup software to restore your backed up files, but it's stored on your dead or damaged drive.
Unlike software you might purchase and download online, it's best to buy physical copies of backup software so that you are sure to have the factory-stamped CD's and other material handy in the event of catastrophe. Don't forget to have that serial number, too, for reinstallation or phone support. (Phone support is quite expensive, while slower e-mail or online support may be free.)
Backup software creates a file that is a catalog or index of the files it has written and when. It is prudent to store the catalog file or similar data on a separate hard drive or on removable media, or by setting up a backup script within your software to copy the catalog separately as a plain file after your main backup has completed.
To recover single files, you typically run the backup software or insert the media that you have used for storing your files and select the ones to retrieve - exercising care to not overwrite folders or directories that you do not want to change.
As with many things, the best time to make a backup is before you experience a crisis. My cousin learned his lesson, and since his dual regime was put into effect, he hasn't had to use archived files. The computers knew they were beaten.
