Re: USB external drive problem

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"R. McCarty" <PcEngWork-NoSpam_@xxxxxxxxxxxxxx> wrote in message
news:%232is$xOdJHA.1336@xxxxxxxxxxxxxxxxxxxxxxx
What you describe is a fairly common issue. On systems where only a
single Enhanced Controller/Hub is available using any USB drive isn't
going to be transfer data very quickly ( ~20.0 Mbs ). Depending on the
number of USB 2.0 devices transfers can be exceedingly slow.


Most PCs only have a single Enhanced Controller/Hub because that is all that
is required. The USB2 system in High speed mode contains bus arbitration to
ensure that things keep moving along nicely. Even without bus arbitration
complex system manage OK. Ethernet is an example of an unarbitrated system
that even has data collisions. It would seem to be a huge bottleneck but in
practice operates quite well. USB2, by the way, operates at 480 Mbs. And
it certainly has nothing to do with delayed write errors which are caused by
something else.

This sounds illogical, but try turning the PC off for 15-30 minutes with
the power cord removed from the Power Supply. Once re-booted, try
your external drive again. *You might want to remove all the other USB
2.0 devices so the external has exclusive access to the controller/hub.


*Very bad* advice for delayed write errors. The delayed write means that
data in the write cache has not been writen back before the device is
disconnected. Unplugging the machine will cause exactly the same problem
but will avoid the error message being displayed.

"Rick Savery" <ricksavery@xxxxxxxxxxx> wrote in message
news:YxMal.189442$AL7.155812@xxxxxxxxxxxxxxxx
Hi

I have a problem with an external bus-powered hard drive. It experienced
a 'delayed write error' and then became invisible to Windows Explorer
and, after re-booting and plugging the drive in again, it show up in
Device Manager as an 'Unknown Device'.

The only way I can access it - at a reduced speed - is to disable the SiS
Enhanced Host Controller. However, this then means that I cannot access
USB 2 devices, like my TV tuner.

I have installed Windows XP SP3, which apparently includes a Hotfix for
just such an issue as this, but with no joy.

It has happened before, and I had to re-format my Laptop's hard drive and
re-install everything, and I really don't want to do that again.

I would appreciate any help or advice you can give

Thanks

Rick



PS I have posted this to a number of newsgroups so apologies if you see
this more than once.






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