Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!mimsy!chris From: chris@mimsy.UUCP (Chris Torek) Newsgroups: comp.unix.wizards Subject: Re: Info sought on system upgrade Message-ID: <4752@mimsy.UUCP> Date: Mon, 15-Dec-86 18:52:37 EST Article-I.D.: mimsy.4752 Posted: Mon Dec 15 18:52:37 1986 Date-Received: Tue, 16-Dec-86 22:24:17 EST References: <776@natmlab.dms.oz> <366@esl.UUCP> Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742 Lines: 29 In article <366@esl.UUCP> mac@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@mimsy.umd.edu