Only one Generic USB SD Reader per computer?


J

John H Meyers

Since a bunch of SD cards takes far less space (and costs less)
than an equivalent bunch of equal capacity flash drives,
I've decided to buy a bunch of cards and a couple of generic
card readers, the latter in a matched pair,
so that I can copy one card to another.

This sounded like a great idea, until I tried to plug in the
second, identical card reader (via a hub), after having successfully
installed and tested the first one (which Windows immediately
accepted and installed, all by itself, as soon as plugged in).

Every time that one of these card readers is already plugged in
and then a second is inserted, up comes this:

[System Settings Change]
Windows 2000 has finished installing new devices.
You must restart your computer
before the new settings will take effect.
Do you want to restart your computer now?

After any number of restarts, I have finally learned
that this is fruitless -- the same thing repeats *forever*,
regardless of how many times a reboot is performed, and
I can never get both card readers working at the same time.

Although *either*one* of my twin card readers can be
plugged in and used, one at a time, if one of them
is already plugged in and recognized, plugging in
the second reader always barfs out the above message,
never gets assigned a drive letter, and won't
simultaneously light up with a card inserted.

The "Unplug or Eject Hardware" wizard
identifies the refused device as "Stop Mass Storage Device"
rather than as "Stop USB Mass Storage Device - Drive (G:),"
as all successfully "mounted" drives would normally say.

However, if I borrow a friend's different-brand card reader,
then one of mine can co-exist with that one, even though
both install as "removable drive" and act exactly the same
in all other respects.

Having plugged in one of mine and one borrowed non-twin reader,
plus even an assortment of Lexar "Jump" drives for good measure,
here's what my Win2K/SP4 Device Manager now says:

Disk drives
[my hard drive here]
Generic USB SD Reader USB Device [the one I borrowed]
Multi Flash Reader USB Device [have two, only one works at a time]
LEXAR JUMPDRIVE SECURE USB Device [three at same time are okay!]

Other devices [yellow "?"]
Mass Storage Device [yellow "?" with yellow "!"]
(this is the second "Multi Flash Reader" just like above)

Storage volumes
Generic volume
Generic volume
...

Universal Serial Bus controllers
Generic USB Hub
Intel(r) 82801AA USB Universal Host Controller
USB Mass Storage Device
USB Mass Storage Device
...
USB Root Hub

Bottom line:

So what's the deal? Is Windows 2000 incapable of using TWO
identical "Multi Flash Reader USB Devices" at the same time,
unless they are made by different manufacturers?
(this pair is by www.dane-elec.com, model SG361A)

Is it Windows' fault? (uses Windows generic drivers),
the manufacturer's fault? Or is there any way around it?

Thanks!

--
 
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U

Uwe Sieber

I bed they have all identical USB hardware serial numbers.
This is a heavy violation of the USB specs and make the
device attached as second one not beeing detected.

I've put together some information and the solution:
http://www.uwe-sieber.de/usbtrouble_e.html#identical_drives


Greetings from Germany

Uwe

Since a bunch of SD cards takes far less space (and costs less)
than an equivalent bunch of equal capacity flash drives,
I've decided to buy a bunch of cards and a couple of generic
card readers, the latter in a matched pair,
so that I can copy one card to another.

This sounded like a great idea, until I tried to plug in the
second, identical card reader (via a hub), after having successfully
installed and tested the first one (which Windows immediately
accepted and installed, all by itself, as soon as plugged in).

Every time that one of these card readers is already plugged in
and then a second is inserted, up comes this:

[System Settings Change]
Windows 2000 has finished installing new devices.
You must restart your computer
before the new settings will take effect.
Do you want to restart your computer now?

After any number of restarts, I have finally learned
that this is fruitless -- the same thing repeats *forever*,
regardless of how many times a reboot is performed, and
I can never get both card readers working at the same time.

Although *either*one* of my twin card readers can be
plugged in and used, one at a time, if one of them
is already plugged in and recognized, plugging in
the second reader always barfs out the above message,
never gets assigned a drive letter, and won't
simultaneously light up with a card inserted.

The "Unplug or Eject Hardware" wizard
identifies the refused device as "Stop Mass Storage Device"
rather than as "Stop USB Mass Storage Device - Drive (G:),"
as all successfully "mounted" drives would normally say.

However, if I borrow a friend's different-brand card reader,
then one of mine can co-exist with that one, even though
both install as "removable drive" and act exactly the same
in all other respects.

Having plugged in one of mine and one borrowed non-twin reader,
plus even an assortment of Lexar "Jump" drives for good measure,
here's what my Win2K/SP4 Device Manager now says:

Disk drives
[my hard drive here]
Generic USB SD Reader USB Device [the one I borrowed]
Multi Flash Reader USB Device [have two, only one works at a time]
LEXAR JUMPDRIVE SECURE USB Device [three at same time are okay!]

Other devices [yellow "?"]
Mass Storage Device [yellow "?" with yellow "!"]
(this is the second "Multi Flash Reader" just like above)

Storage volumes
Generic volume
Generic volume
...

Universal Serial Bus controllers
Generic USB Hub
Intel(r) 82801AA USB Universal Host Controller
USB Mass Storage Device
USB Mass Storage Device
...
USB Root Hub

Bottom line:

So what's the deal? Is Windows 2000 incapable of using TWO
identical "Multi Flash Reader USB Devices" at the same time,
unless they are made by different manufacturers?
(this pair is by www.dane-elec.com, model SG361A)

Is it Windows' fault? (uses Windows generic drivers),
the manufacturer's fault? Or is there any way around it?

Thanks!
 
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J

John H Meyers

I bet they have all identical USB hardware serial numbers.
This is a heavy violation of the USB specs and make the
device attached as second one not beeing detected.

I've put together some information and the solution:
http://www.uwe-sieber.de/usbtrouble_e.html#identical_drives

Thought I'd report on the results (under Win2K):

The "ListUsbDrives" program worked great!

The "GlobalDisableSerNumGen" key did not help,
no matter which way it was set.

However, the "IgnoreHWSerNum" keys worked,
using the info returned by your program.

Your program shows much other information as well,
and I was a bit surprised that in its "Volume" info line for USB sticks,
I find the serial number (MAC) of my Network Interface Card,
rather than of my USB sticks! (should it be otherwise?)

The "Volume" info has no relevance to solving the problem, however
(the real USB serial appears in another listed line, anyway);
just thought I'd mention in case this has any value for you.

I've tried the same USB sticks on a WinXP system
(where Device Manager shows much more info about USB devices,
yet I couldn't find the identical info shown by your program),
and on WinXP they don't cause any problem by having the same serial,
but your program and info certainly save the day for Win2K!

Thanks again for the vital info and great program!

--
 

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