Vertical HD safety


Crotchety UI Nitpicker
I'm a little pressed for desk space at the moment, so I took the vertical stand that came with my external FireWire HD enclosure and stood it up. But I'm worried that this might not be a good idea.

Are all hard drives safe to operate vertically? Because the one I'm using was taken from my old iMac and put in a FireWire enclosure, so I have no way of knowing if it was ever intended for vertical operation. (The drive actually isn't the one that came with my iMac, by the way; I had it replaced one time with a 30GB Quantum Fireball....whatever that is.)

So far it seems to be working fine (I'm doing a large copy operation as I write this). But still, I'm a little uneasy about it. Is it perfectly reasonable to use it vertically, or am I inviting disaster?