Dante Profeta writes:
>I'm wondering about the behaviour of /dev/tty*
>

	I can't answer all of your questions, but I think I can answer
some.

>Why there are some ttys permissions with crw-rw-rw (generally owned by
>root, but some others owned by users), and some others with crw-------
>permissions (owned only by users)?

	What's happening here is that /bin/login (or something else)
is chowning the tty a user logs on to (or has an xterm on) to that user.
For instance, on the machine I'm currently logged into, there are the 
following entries (among others):

crw--w----  1 mynhier  tty       20,   6 Oct 24 02:39 /dev/ttyp6
crw-------  1 mynhier  tty       20,   8 Oct 24 09:40 /dev/ttyp8

They are both ttys that I own by way of xterms.  One of these xterms
I did a 'mesg n' in, which explains why group tty can't write to it.

>
>What is the 'c' bit? I've no docs about it.
>

	Well, you do have documentation on it, you just don't know where
to look.  Try the man pages for ls and mknod.  The SunOS man page (I'm 
currently logged on to a SunOS machine) for ls says:

     The mode printed under the -l option contains 10  characters
     interpreted as follows.  If the first character is:

          d  entry is a directory;
          b  entry is a block-type special file;
          c  entry is a character-type special file;

and other stuff.  Just for curiosity's sake, you might also want to do
something like 'ls -l /dev/*sd0a'.

Chad Mynhier <mynhier@cs.utk.edu>
Lab Engineer, CS Department
University of Tennessee, Knoxville