Installing and maintaining 'talk'

	These instructions are intended to be fairly generic. They were
written for a 3B20. Your milage may vary.

	The talk system is composed of three executable pieces.

	talk		the user interface
	talkdemon	the background process that supervises conversations
	stoptalk	a program for removing the talk msgqueue

	(Yes, I know it's usally spelled 'daemon'. But since my 3B20 has
an 'errdemon' I figured System V wanted to be different. C'est la vie.)

	First, read the 'Makefile' and make any nessecary modifications.
You might want to also change 'talk.h'. Running 'make install' will create
and install the three binaries for you. /usr/bin/talk must run setuid.
This is so that independent 'talk' process can exchange signals. Talkdemon
and stoptalk should have 'other' permissions turned off to prevent regular
users from tampering with them. The owner and group ids of the files are
not important so you can set them as you like.

	After installing the binaries, provisions for automatic startup
and shutdown of the talkdemon should be made. In your startup script
(/etc/rc on my 3B20), at the point where /etc/cron is started, insert
these lines:

	echo talkdemon started
	/etc/talkdemon

and in your shutdown script (/etc/shutdown on my 3B20), before all user
processes are killed, insert these lines:

	echo Talk msgqueue being removed
	/etc/stoptalk

The entry in shutdown is needed because taking the system down to single
user mode doesn't remove msgqueues and because /etc/shutdown kills
user processes with a '-9' which prevents the talkdemon from removing
it's own msgqueue.

	The 'infotalk' program provides status on the state of the demon.
It was initally used for debugging purposes and has been included for
completeness.

Known problems with talk

1)	My version of System V has no high-precision sleep call, so the
main loop of 'talk' runs as fast as the machine allows. I don't think
this leads to any problems other than high CPU usage. If your system
has a fractional-second sleep call, I suggest you use it to reduce talk's
CPU time consumption. Let me know how it goes.

2)	The version of `curses` on my machine has a bug which causes
the cursor to jump to and from the beginning of the current line when
a character is added to the screen. This is not harmful, just annoying.  

Edward C. Bennett
...ihnp4!cbosgd!ukma!ukecc!edward
