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Gem
Premium
join:2005-09-10
kudos:4
Reviews:
·CableOne

1 edit

[XPPro] Windows can't see USB drive from one motherboard

Weird problem viewing our 32GB OCZ USB (FAT32) drive in windows from one of two i915 mohterboards.

We've got two windows XP Pro SP3 32bit i915 S775 computers. One is a laptop, the other is a desktop. Both have the same chipset (ICH6).

The laptop can see our OCZ USB drive and can open files and folders on that drive, but the desktop computer can't even see the OCZ USB drive. Meanwhile the desktop computer can view all our other USB drives.

UPDATE:

After moving the unviewable USB drive from the desktop to the laptop and back to the desktop, the USB self corrected. It is now viewable on both computers.

So, what caused the problem and how did it get "fixed" when it was moved from one computer to the other and back again?



Cudni
La Merma - Vigilado
Premium,MVM
join:2003-12-20
Someshire
kudos:13

Only guessing, that maybe there was some corruption (if unplugged prematurely) which windows corrected on one machine making it good again. Something like that

Cudni
--
"what we know we know the same, what we don't know, we don't know it differently."
Help yourself so God can help you.
Microsoft MVP, 2006 - 2012/13


bkjohnson
Premium
join:2002-05-22
Birmingham, AL
Reviews:
·Charter
reply to Gem

I wonder if this may have to do with USB serial numbers, or the lack thereof. In his "The new old thing blog" Raymond Chen of Microsoft says the following "You may have noticed that if you take a USB device and plug it into your computer, Windows recognizes it and configures it. Then if you unplug it and replug it into a different USB port, Windows gets a bout of amnesia and thinks that it's a completely different device instead of using the settings that applied when you plugged it in last time. Why is that?

The USB device people explained that this happens when the device lacks a USB serial number.

Serial numbers are optional on USB devices. If the device has one, then Windows recognizes the device no matter which USB port you plug it into. But if it doesn't have a serial number, then Windows treats each appearance on a different USB port as if it were a new device.

(I remember that one major manufacturer of USB devices didn't quite understand how serial numbers worked. They gave all of their devices serial numbers, that's great, but they all got the same serial number. Exciting things happened if you plugged two of their devices into a computer at the same time.)

But why does Windows treat it as a different device if it lacks a serial number and shows up on a different port? Why can't it just say, "Oh, there you are, over there on another port."

Because that creates random behavior once you plug in two such devices. Depending on the order in which the devices get enumerated by Plug and Play, the two sets of settings would get assigned seemingly randomly at each boot. Today the settings match up one way, but tomorrow when the devices are enumerated in the other order, the settings are swapped. (You get similarly baffling behavior if you plug in the devices in different order.)

In other words: Things suck because (1) things were already in bad shape—this would not have been a problem if the device had a proper serial number—and (2) once you're in this bad state, the alternative sucks more. The USB stack is just trying to make the best of a bad situation without making it any worse."


Gem
Premium
join:2005-09-10
kudos:4
Reviews:
·CableOne

That's a good thorough explanation. Thank you.

I have been guilty of having two USB flash drives plugged in at one and have not been consistent as to which ports they are plugged into during different computer sessions.

Plus, it is the nature of the devices that we move them from one computer to others and back again.



ZZZZZZZ
Premium
join:2001-05-27
PARADISE
kudos:1
reply to Gem

»www.nirsoft.net/utils/usb_devices_view.html

this portable app lets you control all your USB connections..........wouldn't use anything else and I've never had any problems with any of my devices.
--
Sarcasm is the body’s natural defense against stupidity.


Gem
Premium
join:2005-09-10
kudos:4

Okay, thanks. I'll try it.