LinuxQuestions.org
Visit the LQ Articles and Editorials section
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 10-16-2003, 11:30 AM   #1
jkobrien
Member
 
Registered: Jun 2003
Location: Dublin, Ireland
Distribution: Slackware, LFS, Ubuntu, RedHat, Slamd64
Posts: 507

Rep: Reputation: 30
how are /dev files created?


Hi,

I'm running Slack 9.1 with a 2.4.22 based kernel, which I recompiled (possibly accounting for the following questions though everything else seems to work fine).

Two minor problems have me wondering about device files. How and when are these created? Is it as each device is detected during boot up? How can this process be modified? (alright, meddled with!)

For instance, if I reboot without a disk in my zip drive, I can't mount the disk because there is no /dev/hdd4 file. But if there is a disk in the drive when I boot, the /dev/hdd4 file is created and everything is fine.

A second example, the file /dev/sound/dsp has permissions crw-------, which causes an error message when starting X. This is easily remedied with chmod, but when I reboot it's gone back to crw-------.

Probably these are unrelated problems (presumably some configuration file somewhere) but I'd be glad of any pointers on /dev files or links to further reading.

Thanks in advance,

John
 
Old 10-16-2003, 12:54 PM   #2
acid_kewpie
Moderator
 
Registered: Jun 2001
Location: UK
Distribution: Gentoo, RHEL, Fedora, Centos
Posts: 43,414

Rep: Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966
these entries are most likely to be controlled on your system by devfs, which over the last couple of years has replaced the former flat file format (what a lot of F's!) which actually was an exhaustive list of device entires, which sucked ass. devfsd monitors the system and creates the devices at boot time or whenever a new device is detected on the system. like when i plug a usb digital camera in to the system, it will automatically create entries for it, /dev/sda and /dev/sda1. i'd assume that your zip drive is not fancy enough to be able to be recognised. is that hotplug? not sure... anyway that's what controls it, and you can control it by fiddling with /etc/devfsd.conf and reading the manpage of course
 
Old 10-16-2003, 12:56 PM   #3
acid_kewpie
Moderator
 
Registered: Jun 2001
Location: UK
Distribution: Gentoo, RHEL, Fedora, Centos
Posts: 43,414

Rep: Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966Reputation: 1966
your sound issue is quite possibly nothign to do with this though, and instead down to the PAM security modules. look at /etc/security/console.perms.
 
Old 10-17-2003, 06:42 AM   #4
jkobrien
Member
 
Registered: Jun 2003
Location: Dublin, Ireland
Distribution: Slackware, LFS, Ubuntu, RedHat, Slamd64
Posts: 507

Original Poster
Rep: Reputation: 30
Many thanks for the helpful responses. It seems that the zip problem is something I'll have to live with until the 2.6 kernel is released according to this guy but I was able to take care of the /dev/sound/dsp problem and learned something at the same time!

John
 
  


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
sata drive identified by module, but no /dev created! ttilt Linux - Hardware 0 09-17-2005 03:28 PM
/dev/hd* created after fstab is run? eurleif Debian 3 07-18-2005 10:10 AM
Can we access the newly created files after dd if=hda6_last_mon_backup of=/dev/hda6 murugesan Linux - Software 0 03-29-2004 08:42 AM
how are /dev entries created? quatsch Mandriva 3 03-10-2004 09:41 AM
No USB module loaded /dev/sda1 not created jfi Mandriva 7 02-29-2004 02:11 PM


All times are GMT -5. The time now is 07:32 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