External USB hard drive hot plug requires reboot

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joneill809

I recently purchased 6 low end hard drive enclosures, "PT Brand"
PT-350U2-BL enclosures that were on special. All 6 are USB 2.0 IDE
interfaces. I installed 80 GB WD 7200 RPM drives in the enclosures,
all set to "master" as specified by the manufacturer.

All exhibit the same flaw: they are detected when first inserted into a
USB port, but if I attempt to stop the device, remove the cable and
reinsert the device, it will not be recognized. I cannot attach the
same device or another of the 6 devices. I can insert any other USB
device without a problem.

I can insert these drives once per boot cycle. The only way to fix
this behavior is to reboot the machine; after that I can plug any of
the six drives into a USB port and it will be recognized, but I cannot
plug any one of these devices in a second time. A few notes:

(*) This has been tested on two XP machines and a 2003 server. All
exhibit the same behavior.

(*) All systems have the latest service packs and hot fixes installed

(*) Three other models of external disk enclosures work without a
problem

(*) I am using the "Safely Remove Hardware" wizard to eject the drives

(*) The drives are not present in the disk manager following the second
insertion. There are no drive letter conflicts.

Granted these are cheap pieces of junk, but I am having trouble getting
a response from the vendor. I'd like to determine the cause of the
issue but my instincts tell me that this is purely a hardware design
flaw that I may not be able to work around (given the fact that all 6
exhibit the same behavior). Hopefully this is not the case.
 
I recently purchased 6 low end hard drive enclosures, "PT Brand"
PT-350U2-BL enclosures that were on special. All 6 are USB 2.0 IDE
interfaces. I installed 80 GB WD 7200 RPM drives in the enclosures,
all set to "master" as specified by the manufacturer.

All exhibit the same flaw: they are detected when first inserted into a
USB port, but if I attempt to stop the device, remove the cable and
reinsert the device, it will not be recognized. I cannot attach the
same device or another of the 6 devices. I can insert any other USB
device without a problem.

I can insert these drives once per boot cycle. The only way to fix
this behavior is to reboot the machine; after that I can plug any of
the six drives into a USB port and it will be recognized, but I cannot
plug any one of these devices in a second time. A few notes:

(*) This has been tested on two XP machines and a 2003 server. All
exhibit the same behavior.

(*) All systems have the latest service packs and hot fixes installed

(*) Three other models of external disk enclosures work without a
problem

(*) I am using the "Safely Remove Hardware" wizard to eject the drives

(*) The drives are not present in the disk manager following the second
insertion. There are no drive letter conflicts.

Granted these are cheap pieces of junk, but I am having trouble getting
a response from the vendor. I'd like to determine the cause of the
issue but my instincts tell me that this is purely a hardware design
flaw that I may not be able to work around (given the fact that all 6
exhibit the same behavior). Hopefully this is not the case.
Click to expand...

Note that Western Digital hard drives really have 3 jumper settings:
Single, Master and Slave. When used as a single drive, whilst even in
an USB enclosure, the drive is unjumpered as a Single. Open one of the
USB enclosures and test with the HD setting as "single", or unjumpered.
 
Thanks for the tip. Looks like that was it. It turned out that I had
used non-WD jumpers that were a bit shorter than the originals. All
the drives were set to dual channel master, so I used needle nosed
pliers to remove the jumpers and the plastic came off but the bits of
metal were still lodged in the back of the jumper housing. Bizarre -
that's a first for me. Just took me a day to cool off and use
someone's fresh perspective. Thanks for the recommendation - they're
hot plugging now.
 
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