Dan Butler's
TNPC Newsletter

Avoiding Disk Defragmenter Disasters

by Lee Hudspeth

We've been promoting the frequent use of Disk Defragmenter tools for many years, typically as part of a routine system upkeep process, or when doing system setups and exercising the drive(s) and operating system. Until recently none of us had been burned while running Defrag. A short time ago while on a field call, the tables turned, and things got ugly. Here's what happened, and what we can all learn from the fiasco.

The history: an old (circa 1995) third-party video driver launched its proprietary screen saver at about 75% completion on the defrag. Win95 displayed the highly undesirable, white, chunky, system modal (meaning: you can't switch out to any other application) message box "Windows cannot read from drive C:". This eventually cascaded to an explicit Defrag error message, then another "Windows cannot read from drive C:" message box, a three-finger salute, and a thoroughly unreadable drive. Long story short: the drive had crashed, as confirmed by the PC manufacturer's diagnostic software. We'll never know if the crash was software induced or not, so we don't blame Defrag per se, but in retrospect we sure wish we had deactivated that screen saver first.

We were also in trouble because we had neglected to make a bootable diskette with real mode drivers for the CD-ROM drive (we did have a plain vanilla bootable diskette), so we couldn't immediately start installing a replacement drive and rebuilding the operating system. Fortunately, we downloaded the drivers from Hitachi's Web site on a PC down the hall and were back in business with just a few minutes delay; even more fortunate, the crashed drive had no data on it, just applications.

Things to remember: (1) We didn't violate this rule this time, but it's worth repeating... Backup all data prior to running Defrag. This means even if you're letting System Agent run Defrag in the background, make sure you've got your data backup scheduled to precede Defrag. (2) Never work on a system, no matter how trivial you think the work will be, without reboot- verifying the boot diskette and its real-mode CD-ROM device drivers. (3) Run Defrag only when no other applications are running (so you might want to always do this manually instead of via System Agent).