With the external SCSII zip drive I had, it had to be turned on when the Mac computer booted else the computer (Mac OS) would not see it (same as other SCSII devices.) That was both good & bad. Since I didn't always need to have it turned on. I'm not sure if it works the same way with Windows. If not, then arguably you could flip the zip drive powerboard power switch on & off as you needed to use it.