[geeks] Little Falls 2 System Power Consumpion Question

[Micah R Ledbetter]

On Dec 13, 2008, at 8:11 PM, Patrick Giagnocavo wrote:
> You are very lucky you didn't fry the motor on the hard drive.  I have
> seen cases in my own experience where under-powering drives results in
> them being screwed out and requiring a new PCB (basically the hard  
> drive
> motherboard).

Really? I thought that people slightly underpowered laptop hard drives  
all the time -- I don't remember the numbers off the top of my head,  
but doesn't USB provide less than the maximum power that 2.5" IDE  
disks can suck? IIRC 2.5" IDE disks can require up to 5.5v, according  
the its spec, and USB doesn't have to provide more than 4.5v,  
according to its spec (the numbers could be wrong, I can't remember  
very well). Some laptop drives never thirst for their potential  
maximum power draw, so there is never a problem, but some do.

I ran into this problem once, where any time I had heavy read or write  
access on an external bus-powered USB drive, it would fail and the OS  
would see that the disk had been detached without first ejecting it. I  
tried the drive in two different enclosures, and the behavior  
persisted. IIRC, Firewire provides a little bit more, and so I'm going  
to get a bus-powered Firewire<->laptop IDE enclosure whenever I get  
around to it.

  - Micah