As many are aware, external drives tend to spin up even when they aren't necessarily needed. For example, on Mac OS X, they start whizzing away whenever you try to save something locally, even if you've made no indication that you wish to save that something to the external drive. If you are like me, and only use your external drive(s) to mirror the hard drive(s) in your machine during the wee hours of the morning, you likely find this spin-up process very annoying, not least because it always takes a few machine-immobilizing seconds.
After having been irritated by this nonsense one too many times, I set out to solve the "problem." My first thought was to crontab a couple of shell scripts to run just before and after SuperDuper! did its thing; the shell scripts would mount and unmount the drive. Soon after I started whipping up the scripts, I noticed that SuperDuper! had the native ability to launch scripts before and after a scheduled backup — no crontab needed. Nice.
With this little bit of fortuitous knowledge bouncing around in my head, I decided to go a step further and see what would happen if a scheduled backup began while my external drive was unmounted and no scripts were defined. I'll tell you what happened — SuperDuper! didn't miss a beat. It mounted the drive, did its backup thing, and then unmounted the drive. Very nice.
Now, did I half-expect it to do that? Yes, because it's so obvious. But, let's be honest, how often do you expect something to work a certain way (because it's the only logical way to do it) and it doesn't? Yeah, all the time.
Knock on wood, that particular problem hasn't reared its ugly head since I wrote about it. ↩