Info sought on system upgrade

[Chris Torek]

In article <366 at esl.UUCP> mac at esl.UUCP (Mike McNamara) writes:
>One thing I would highly recommend to anyone trying to upgrade
>their system performance is a terminal server.  I am speaking about
>a box which sits on the ethernet, allows you to plug in ~16 terminals,
>and allows those terminals to communicate to any box that speaks
>TCP/IP.  This removes the high cost of interrupt per character to
>and from your terminal....

But be careful!  On standard 4.2 and 4.3BSD systems, a telnet or
rlogin session presents considerably more load than a directly
connected terminal, because the telnet and rlogin servers run in
user code and require many context switches to transfer characters
in and out of ptys.  With kernel hacks such as those from Rutgers
or NYIT, this overhead is considerably reduced, though a TCP
connexion is still more of a load than a good hardware terminal
multiplexor---unless perhaps your network interface implements
TCP internally, in which case you should look *very* closely to
make sure it is bug-free.

Incidentally, if your multiplexors interrupt on every character,
you may be well advised to replace them.

>It also allows users to select which machine they would like to
>log in to....

This too is an important consideration.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7690)
UUCP:	seismo!mimsy!chris	ARPA/CSNet:	chris at mimsy.umd.edu