LinuxQuestions.org
Go Job Hunting at the LQ Job Marketplace
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Hardware
User Name
Password
Linux - Hardware This forum is for Hardware issues.
Having trouble installing a piece of hardware? Want to know if that peripheral is compatible with Linux?

Notices

Reply
 
Search this Thread
Old 10-24-2010, 10:17 PM   #1
crosstalk
Member
 
Registered: Jul 2010
Distribution: Gentoo, Debian, Mint, Xubuntu
Posts: 150

Rep: Reputation: 35
Stupidly ran "cat /dev/urandom > /dev/mem", worried I broke firmware


Well, I was playing around with /dev/mem, and just to see if I could write to memory with it, I ran
Code:
cat /dev/urandom > /dev/mem
When I rebooted, I found that X11 didn't recognize either my synaptics touchpad or my desktop background.

Is it possible I overwrote some important firmware, or did I just nuke a couple of important files (which I can repair)?

I am running Gentoo Linux.

Thank you for any help.

EDIT: On the third boot, it recognized my mouse correctly. I am currently running "emerge -e world". I feel stupid -- I should've realized that overwriting kernel memory could mess with filesystems.

Last edited by crosstalk; 10-24-2010 at 11:09 PM. Reason: More info
 
Old 10-25-2010, 06:09 PM   #2
bulls_i3
LQ Newbie
 
Registered: Jan 2010
Posts: 20

Rep: Reputation: 2
/dev is not a real part of the filesystem, but just contains pointers to your devices.

AFAIK, rebooting should fix the problem, since nothing was actually "written".

(Although, you could have corrupted your memory in such a way that caused the kernel to do something unexpected, e.g. overwrite some important files, in which case a "write" did happen. But I think a scenario like that is extremely unlikely. I think you'd get weird behaviour and probably crashes before that happens.)

Try booting into a non-X11 runlevel, and see if you can find any problems. It seems like your currently problem might be X11 specific.
 
Old 10-25-2010, 06:27 PM   #3
crosstalk
Member
 
Registered: Jul 2010
Distribution: Gentoo, Debian, Mint, Xubuntu
Posts: 150

Original Poster
Rep: Reputation: 35
That was what I wanted to hear.

Since it didn't work after I rebooted, I knew that it had either messed with some files or with the firmware for the touchpad (if the touchpad has firmware). I just wanted to make sure it couldn't be the latter (which would be harder to fix).

Until I start X, everything seems to run fine. It has been running all day (9.5 hours) doing an "emerge -e world" (which reinstalls everything, for non-Gentoo folk) (it's a 1.6 GHz Pentium M-based laptop).

Thank you.

(I'll add [solved] after I can test it.)

EDIT: Plus or minus, almost everything seems to work.

Last edited by crosstalk; 10-26-2010 at 08:47 AM.
 
  


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
Startup Hang after "Using /etc/random-seed to initialize /dev/urandom" DotMatrix Slackware 5 02-26-2010 01:34 AM
Android permission to open("/dev/mem",...) eseitelbach Linux - Software 0 11-04-2009 10:05 AM
What would happen if I where to cat /dev/mem > /dev/null Joey.Dale Linux - General 11 07-26-2009 01:46 PM
"Bad address" reading /dev/mem chvince Linux - General 1 12-03-2008 07:06 PM
What is adsp0? and why cat /dev/urandom >/dev/adsp0 give me "no such device"? haimeltjnfg Linux - Hardware 2 05-09-2004 11:54 PM


All times are GMT -5. The time now is 11:50 PM.

Main Menu
Advertisement
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