Pushing beyond the frontier

This might be because of my typically russian trait of thinking "what if?" about the most unusual things but here's something thats been torturing me lately.

You know the usb enclosures for laptop hard drives. They normally have 2 usb tails (an extra one to draw more power). Well they are both proper usb plugs, not just with power pins. So the question is - what would happen if you plugged one hard drive into two pcs simultaneously? I am not willing to risk my hdd, and i am not suggesting that someone else should. I am sure no damage would occur to the pcs, and the hdd should physically be fine, but there's probably a chance of losing data if you try to write to the hdd.

If someone knows (through theory of how it all works) what would happen. Or if anyone is willing to try (you would be doing it at your own risk - try to use the pc you don't care about and back up any data on hdd - and only do it if you are prepared to lose it all and are not going to go after me afterwards). Or if you would like to speculate - post your thoughts/experiences here.

I was thinking of sending an email to Billy, after all he can afford to blow a couple hundred pcs if it all goes wrong, but something tells me he ain't gonna bother.

P.S. Disclaimer - once again, any experiments you do are at your own risk.

youl find most arent 2 usb plugs but one data and power plug and the other just power if anyything atall mine works fine with just the one plug but if try and use only the other plug it just spins up and wont be recognised with windows

I just tested each plug on its own and i think you are right... I thought it used to run on either plug but i might have been wrong. Ah well, never mind, this question will remain unanswered.

i think when u see these advertised they claim that it might need the second plug and comes with it just to make you feel as if they have done some reasearch and are covering all options
i think its part of the usb standard to be able to deilver so much voltage and milliamps so very few motherboards will not power up the drive with ne plug unless maybe you have tons of stuff being powered from it maybe

Theres definately times when it doesnt work with just the one cable and needs 2.