Path: utzoo!utgpu!water!watmath!clyde!cbosgd!mandrill!rynes
From: rynes@mandrill.CWRU.Edu (Edward M. Rynes  Esq.)
Newsgroups: comp.mail.uucp
Subject: Re: 4800 > 9600 ?
Message-ID: <2337@mandrill.CWRU.Edu>
Date: 8 Jan 88 22:23:25 GMT
References: <426@taux01.UUCP>
Reply-To: rynes@mandrill.CWRU.Edu (Edward M. Rynes  Esq.)
Organization: CWRU Dept. of Computer Engineering, Cleveland OH
Lines: 43

In article <426@taux01.UUCP> amos%taux01@nsc.com (Amos Shapir) writes:
>Here's the situation: 2 systems running sysV.3, sitting on the same table,
>and connected by a direct line. There's no significant noise, and we can do
>cu and uucp at speeds up to 9600 baud. BUT: while at up to 4800 baud transfer
>rates look consistent with the baud rate, at 9600 baud uucp behaves strangely -
>it seems that after passing each packet, it stops for about 10 seconds. No
>error messages are produced.
>
>Is this a common problem, or is it just us? Can anyone give us pointers
>for debugging this? It's ok to uucp at 4800 baud, but we occasionally have
>to use the same line for terminals, and switching baud rate is a nuisance.
>
>	Thanks very much,
>-- 
>	Amos Shapir			(My other cpu is a NS32532)
>National Semiconductor (Israel)
>6 Maskit st. P.O.B. 3007, Herzlia 46104, Israel  Tel. +972 52 522261
>amos%taux01@nsc.com (used to be amos%nsta@nsc.com) 34 48 E / 32 10 N

  We have the same problem connecting a Vax to a Data General over a
serial line.  After much confusion and too many hours of debuging I
came to the conclusion that one or both machines could not keep up
with the conversation at 9600 baud and some of the data was lost.
There does not seem to be any flow control between the two systems.
The master sends a packet then waits for a reply from the slave. 
(usualy about 10 seconds) if no reply is received it resends the
packet.  The first few packets seem to go OK but after that buffers
start to fill and eventualy a packet will get lost.  A lost packet
will cause the slave to not respond causing the master to wait.  The
wait allows the buffers on the slave to empty out allowing the next
few packets to get through.  At 4800 baud both systems seem to keep
up with the flow of data thus no lost packets and no waiting.

   This may or may not be the problem you are having but the results
are the same.  Good luck.
______________________________________________________________________________

Edward Rynes	Unix Engineer		|      "Give me what I want, and all I
A. R. Jennings Computing Center		|        Can think about is losing it.
Case Western Reserve University		|              I'm losing it!"  K.H.
Cleveland, Ohio   44106			|
(216) 368-2982	rynes@mandrill.CWRU.Edu | {cbosgd|decvax|sun}!mandrill!rynes
______________________________________________________________________________