LinuxQuestions.org
Register a domain and help support LQ
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Software
User Name
Password
Linux - Software This forum is for Software issues.
Having a problem installing a new program? Want to know which application is best for the job? Post your question in this forum.

Notices

Reply
 
Search this Thread
Old 08-13-2004, 10:48 AM   #1
furryspider
Member
 
Registered: Feb 2004
Location: by the Bavarian Sea
Distribution: Slackware 14.1
Posts: 56

Rep: Reputation: 15
Can't mount 2 usb-storages after one another on same port?


Hi,

I'm on Slack10, using at times a 128MB USB-RAM-Stick as well as a digital camera. Both I can access through /dev/sda1.

However, whenever I mount either of the storage devices, and unmount them after the data transfer, I cannot mount the other one anymore. When trying to, mount tells me that /dev/sda1 isn't a valid block device. I am able to mount the SAME storage device again, though.
E. g.:
Mount Camera, copy contents, unmount camera
then:
a) mount usb-ramstick => not a valid block device
b) mount camera again => no problem

I noticed that two processes become active whenever I mount a usb storage device, and stay active even after I unmount the device. The processes are:
usb-storage-0
scsi_eh_1

Does anybody know what's going on?

Thanks,
FurrySpider
 
Old 08-13-2004, 02:06 PM   #2
Dark_Helmet
Senior Member
 
Registered: Jan 2003
Posts: 2,786

Rep: Reputation: 369Reputation: 369Reputation: 369Reputation: 369
I don't have a definitive answer, but a guess...

The system might save device information when you mount it, meaning that it associates /dev/sda1 with a particular USB device identifier. If you plug in another device that no longer matches, the system might then be forced to associate it with a different device: /dev/sdb1 for instance.

Give that a shot; try to mount the second device using /dev/sdb1. Like I said, it's a guess, and the worst thing that could happen is the system tells you "/dev/sdb1 is not a valid block device"
 
Old 08-14-2004, 02:24 PM   #3
furryspider
Member
 
Registered: Feb 2004
Location: by the Bavarian Sea
Distribution: Slackware 14.1
Posts: 56

Original Poster
Rep: Reputation: 15
Spot on Dark_Helmet! It works like you said!
I was actually trying to find the place where the system would store that 'device information', so I could go and tamper with it. I just didn't, and still don't have a clue where that might be.

Anyway, following your directions I don't have to bother anymore. Thanks!
 
Old 08-14-2004, 03:03 PM   #4
Dark_Helmet
Senior Member
 
Registered: Jan 2003
Posts: 2,786

Rep: Reputation: 369Reputation: 369Reputation: 369Reputation: 369
Glad I could help!

And the "device information" I referred to earlier is probably stored in RAM somewhere. It might be part of the USB modules loaded for the device, stored in some special kernel memory, or any number of other places. Since you could plug in either device after a reboot and access it as /dev/sda1, that suggested the information was lost on reboot, and that implies RAM...

Anyway, useless trivia... the important part is, you're good to go
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
After plug in apacer ht202 usb mass storage into usb port. Nothing appear. tellmeimhong Linux - Hardware 3 02-04-2006 02:32 AM
Using an USB port as a standard DB9 Serial Port Lsteele Linux - Newbie 1 10-22-2005 09:48 AM
USB drive mount double mount issue pazzport Ubuntu 3 10-10-2005 08:28 PM
linux locks up when usb mouse attached to usb port during startup. BGuy891653 Linux - Hardware 0 02-08-2004 05:26 PM
mount usb module then mount usb hard drive guanyu Linux - Hardware 1 10-08-2003 11:50 AM


All times are GMT -5. The time now is 06:56 AM.

Main Menu
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration