Macbook Pro - USB Hard-drive Problem

I have a USB 2 80 GB portable (bus powered) hard drive which I am
using with my MacBook Pro 2.4Ghz.

I notice that the hard drive only works, when plugged into the USB
port on the right hand side. When plugged into the USB port on the
left hand side, the drive refuses to spin, and thus, refuses to mount.
However, the USB port on the left hand side is working, as my flash
drive, keyboard, and mouse all work without fail.

Any ideas?

Thanks

In article
,
Bosco836 wrote:

> I have a USB 2 80 GB portable (bus powered) hard drive which I am
> using with my MacBook Pro 2.4Ghz.
>
> I notice that the hard drive only works, when plugged into the USB
> port on the right hand side. When plugged into the USB port on the
> left hand side, the drive refuses to spin, and thus, refuses to mount.
> However, the USB port on the left hand side is working, as my flash
> drive, keyboard, and mouse all work without fail.

the problem is that the usb specification states that it can supply a
maximum of 5 volts at 500 milliamps. unfortunately, that is not enough
to spin up a hard drive, which generally wants about 1 amp or so.
that's why many usb bus powered drives have a dual usb cable.

apparently, one side of the macbook pro can supply a little more power
than the other and enough to spin up the drive. that's also not the
first time i've heard of that happening. usb only needs to officially
supply 500ma, so consider it lucky that it works at all.

for bus powered drives, firewire is the best way to go, as it can offer
about 10-15 watts of power, more than enough for a laptop drive (even
two can be connected). plus, firewire 400 is faster than usb. the
macbook pro also offers the option of firewire 800, although the
difference won't be that huge on a laptop drive versus fw400.