Priority messages in Unix

[Anton Rang]

In article <539 at lakesys.UUCP> chad at lakesys.UUCP (Chad Gibbons) writes:
>  On most BSD-derivative systems no user other than the owner has
>access to your tty, nor can you modify your own.  Talk requests and such
>are done through a system of daemon processes which control user access
>to each other.  This was done in order to remove the ever frustrating
>moment when someone does a "cat</etc/hosts>/dev/ttyxx&" to your terminal.
>-- 
>D. Chadwick Gibbons, chad at lakesys.lakesys.com, ...!uunet!marque!lakesys!chad

  Unfortunately, at least in SunOS 3.4 (4.2-BSD derived), this isn't
quite true.  Yes, talk requests etc. are done through a system of
daemons.  But you don't get talk requests etc. unless you execute
'mesg y', which turns on world write access to your /dev/tty, which
allows "cp /etc/hosts /dev/ttypxx" (or your favorite command...I
always liked echoing a power-on reset sequence :-)....

+---------------------------+------------------------+----------------------+
| Anton Rang (grad student) | "VMS Forever!"         | "Do worry...be SAD!" |
| Michigan State University | rang at cpswh.cps.msu.edu |                      |
+---------------------------+------------------------+----------------------+