[not sure if this is the right forum for this, but i suspect others on this list might be interested so ... there you go.] as part of a device driver course i may very well be teaching in the near future (still waiting to hear), i'm thinking of adding a sizable section on how udev works (after i figure all that out, of course.) currently, the canonical udev document is this one: http://reactivated.net/writing_udev_rules.html but as good as that doc is, it's obvious that it's getting a bit dated. for example, it refers to separate udev-related utilities such as udevinfo, udevtrigger and so on when, these days, there's just "udevadm" with the appropriate subcommand, so that's something that could be tidied up. other picky things to be updated include claiming that the default udev rules file is /etc/udev/rules.d/50-udev.rules when -- at least on my ubuntu system -- it's /lib/udev/rules.d/50-udev-default.rules. again, not serious, just something that could be corrected. (mind you, i don't know if the udev file and directory structure differs drastically on other distros, something i'll look into.) and sometimes the documentation is not clear on some issues. for instance, are the only two possible entries for the udev.conf file udev_root udev_log the man page for "udev" suggests that, i just wasn't sure whether there were any other possibilities. finally, i was checking the default udev rules file on my ubuntu system and, right at the top, i read: SUBSYSTEM=="block", SYMLINK{unique}+="block/%M:%m" SUBSYSTEM!="block", SYMLINK{unique}+="char/%M:%m" AFAICT, there is nothing in the udev man page that explains the "SYMLINK{unique}" notation. it's easy enough to see how it creates that set of symlinks based on major and minor numbers, but what's with the "unique"? oh, and for this udev tutorial, i want to come up with some real, hands-on examples, so that people can see what's happening with events when they do stuff like insert USB keys and so on. anyway, this will undoubtedly take more than a few days but feel free to use this as a thread to go through the current document, check it against your system, post differences or updates, and i'll collect them all and eventually write up an updated version and post it somewhere. rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================