disappearing device files

[Steve Kleene <skdeb@syrano.acb.uc.edu>]

When I tested gnome on my recent etch install, I noticed that it mounted my
USB flash drive on /dev/sdc1.  So when I run from a command line under fvwm
(most of the time), I also mount the flash on sdc1.  So that I wouldn't have
to remember the drive name, I did the following:

  cd /dev; ln -s /dev sdc1 flash

I've done this for years, and it works fine.  Now, though, every time I boot,
the /dev/flash link disappears.  And recently, /dev/sdc1 disappeared too.
Now if I recreate sdc1 with mknod, it functions fine, but it disappears after
any reboot.  There are plenty of other symbolic links that came with the
system (e.g. cdrom -> hda), and they don't disappear.

What's going on?  Are device files checked against some official registry and
deleted if they're unrecognized?

Thanks.