[ltp] External hard drive failing?

[Stefan Monnier]

> I have a Verbatim external USB 3.0 hard drive.
[...]
> The ports are USB 2.0.

If this is really a "hard drive" (with actual rotating disks inside
rather than, say, flash memory), then a common problem is that those
disks can occasionally (often during spin-up) require an amount of power
that's beyond the max power delivered by USB-2.0 (~2.5W).

For this reason, many USB-2.0 enclosures provided 2 USB connectors (one
for data and one for extra power) or some other way to provide
additional power.

USB-3.0 pushed that limit to 4.5W which largely solved the problem, so
your enclosure probably expects all the power to come from the one port.

Of course, a USB-2.0 port is allowed to provide more than 2.5W, and
disks don't always eat up more than that, so in practice a single
USB-2.0 port often works fine, tho it might depend on luck (and it
might work unreliably, and depend on factors such as the current
machine load, ambient temperature, the age of the captain, ...).

> This is a USB only hard drive.  Not an SATA in an enclosure.  I will try
> cleaning the contacts.

I've never heard of any USB-only HDDs.  AFAIK they are always some kind
of SATA drive inside some SATA<->USB enclosure.  Some of those
enclosures are not designed to be easily opened, admittedly, but I've
never heard of ones where you can't get the underlying SATA drive out
with a bit of determination.


        Stefan