John, Comments in-line On 23/09/05, John R. McPherson <jrm21(a)cs.waikato.ac.nz> wrote:
On Fri, Sep 23, 2005 at 10:54:29AM +1200, Ian McDonald wrote:
Hi there,
Questions: 1) How are major and minor device numbers assigned? e.g. a webpage will say type "mknod /dev/video0 c 81 0". I understand the syntax but why 81 and 0 for the major and minor numbers?
Listed in /usr/src/linux/Documentation/devices.txt
Thanks.
2) How do these devices you create interact with udev? Permissions and other things seem to disappear after a reboot. Should I be using udev instead of mknod?
Yes. most distros these days seem to put /dev on a "tmpfs" memory-only mount, so it gets regenerated by udev each boot. You shouldn't need to use mknod manually; udev makes device files for all the detected devices attached to your system if you have kernel support for them.
OK.
What type of webcams are you having problems with?
A firewire one from OrangeMicro (iBot) and a Dick Smith one which is ov51x based. (NB I haven't tried your code yet mentioned in Wiki as trying to get it working with Video4Linux at present)
URLs to articles would be appreciated or just people's comments. I promise to Wiki what I find out as I have been doing for most of my discoveries...
There are a few articles linked to from www.wlug.org.nz/UDev
Cool. I will add some general comments.
John
Ian