Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!rutgers!clyde!cbatt!cwruecmp!hal!ncoast!wb8foz
From: wb8foz@ncoast.UUCP (David Lesher)
Newsgroups: net.periphs,net.micro.att
Subject: Re: Buffer overflow in AT&T 4425 video display terminals
Message-ID: <1645@ncoast.UUCP>
Date: Tue, 28-Oct-86 13:37:31 EST
Article-I.D.: ncoast.1645
Posted: Tue Oct 28 13:37:31 1986
Date-Received: Wed, 29-Oct-86 21:50:20 EST
References: <1384@kitty.UUCP> <2500@gitpyr.gatech.EDU>
Reply-To: wb8foz@ncoast.UUCP (David Lesher)
Organization: North Coast Public Access UN*X, Cleveland, OH
Lines: 40
Keywords: AT&T 4425, poor display throughput
Xref: mnetor net.periphs:586 net.micro.att:1639

In article <2500@gitpyr.gatech.EDU> jkg@gitpyr.UUCP (Jim Greenlee) writes:
>In article <1384@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes:
>>	Since I was only running at 9,600 baud, and since the 4425 is supposed
>>to be an _improved_ terminal, I decided not to enable the DC1/DC3 mode.  No
>>problem at first - until I did a uulog, and watched the screen barf after
>>about 50 lines.  Any large text display (without attributes, even) causes the
>>screen to barf and lose characters, lines, etc. UNLESS the DC1/DC3 mode is
>>enabled.
>>	Why is this?!  These 4425's seem to have slower character throughput
>>than their predecessor 4415's.  I get FULL 9,600 baud throughput on other
>>VT100 clones, like the Datamedia DT-100. 
>
>I would say that a terminal which can achieve full throughput at the higher
>baud rates would be the exception rather than the rule. The "baud rate" is
>not necessarily the "baud rating", but is simply a number which guarantees
>that the sending and receiving units will be synchronized to a common clock.
>This is absolutely necessary for serial communications since there typically
>is no acknowledgement between the two devices on a character-by-character
>basis (as with most parallel connections).
>The Shadow
>Georgia Insitute of Technology, Atlanta Georgia, 30332
>...!{akgua,allegra,amd,hplabs,ihnp4,seismo,ut-ngp}!gatech!gitpyr!jkg

I did some work a few years ago to "load down" a CSMA/CD LAN to see
what it really offered in throughput. One of my biggest problems was that
NO (text) terminal in the house could keep up. The only box fast enough
(Note this was 9600) was a $$$$ TEK graphics terminal. I do not recall
the # of it, but it had a 80286 aux processer built into it, if that helps.
It offered speeds up to 38.4, but I never found a fast enough source to test
that aspect.

-- 

		      decvax!cwruecmp!ncoast!wb8foz
			ncoast!wb8foz@case.csnet 
		(ncoast!wb8foz%case.csnet@csnet-relay.ARPA)

    	         		"SERIOUS?
		Bones, it could upset the entire percentage!"