XPJoe said:
My PC needed to have Windows XP SP2 re-loaded recently. Since then, I can't
use any USB storage devices (zip, flash drives or cameras) - all USB drives
are no longer recognized. The only drives shown in Disk Manager are the CD
and DVD drives.
How can I remedy this? Thanks.
The bottom two pictures here, show the section of Device Manager
associated with USB entries. If you'd mentioned your computer
make and model number, it might be easier to figure out what
entries would make sense there. But for a first check,
see if there are any marks on the entries, that indicate
the entry has a problem. Open the device entry if so,
and see if an error number or error text is present.
http://www.usbman.com/Guides/checking_for_usb_2.htm
For example, I have a VIA chipset, and this is what my USB
section looks like. This is with no USB flash stick plugged in.
USB Root Hub 5.1.2600.5512
USB Root Hub 5.1.2600.5512
USB Root Hub 5.1.2600.5512
USB Root Hub 5.1.2600.5512
USB Root Hub 5.1.2600.5512
VIA Rev 5 or later USB Universal Host Controller 5.1.2600.5512
VIA Rev 5 or later USB Universal Host Controller 5.1.2600.5512
VIA Rev 5 or later USB Universal Host Controller 5.1.2600.5512
VIA Rev 5 or later USB Universal Host Controller 5.1.2600.5512
VIA USB Enhanced Host Controller 5.1.2600.0
When the USB flash is plugged in, it adds this entry. (I used
a copy of Everest free version, and its report tool, so I could copy and
paste the text here.)
USB Mass Storage Device 5.1.2600.0
Note that, in the ten items shown in that list above, those
are not "ports". Those entries correspond to logic blocks
inside the Southbridge (or a separate USB card). One low
speed logic block controls two ports in a stack. One
high speed (enhanced) logic block, can control a larger
number of ports. A port is "bound" to either a low speed
or a high speed logic block.
Those are some rough rules of thumb - there are a few
exceptions. For example, some of the latest Intel Southbridge
chips, have two Enhanced entries, because they included an extra
USB2 logic block to share the data transfer load. That helps
improve performance with USB storage devices.
If you want another tool to play with, try UVCView. Originally,
this tool was hosted on the Microsoft web site, but has since
been removed. There are two places you can still find a copy.
Watch how the display cnanges (or not), when the USB flash
is plugged in. The response really shouldn't be that much
different, than what happens in Device Manager. The MD5sum
quoted below, is the sum for a copy downloaded from Microsoft
when it was available.
*******
ftp://ftp.efo.ru/pub/ftdichip/Utilities/UVCView.x86.exe
http://www.users.on.net/~fzabkar/USB_IDs/UVCView.x86.exe
File size is 167,232 bytes.
MD5sum is 93244d84d79314898e62d21cecc4ca5e
This is a picture of what the UVCView info looks similar to.
http://www.die.de/blog/content/binary/usbview.png
Some information on the parameters seen in UVCView.
http://www.beyondlogic.org/usbnutshell/usb5.htm
*******
HTH,
Paul
