Path: utzoo!utgpu!jarvis.csri.toronto.edu!helios.physics.utoronto.ca!ists!yunexus!maccs!cs4g6ag
From: cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Problem: modem errors w/ disk cacheing?
Keywords: modem, disk cacheing, RLL, comm errors
Message-ID: <25EEC2D8.21970@maccs.dcss.mcmaster.ca>
Date: 2 Mar 90 19:00:39 GMT
References: <1421@oak8.UUCP>
Reply-To: cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn)
Distribution: comp.sys.ibm.pc, comp.dcom.modems
Organization: McMaster University, Hamilton, Ontario
Lines: 25

In article <1421@oak8.UUCP> hamilton@cell.mot.COM (Danial Hamilton) writes:
$My environment:
$I'm running a 25 Mhz 386 with a Seagate ST277R-1 65MB 28ms RLL drive.
$I'm using a WA6-VR 1:1 controller with disk cacheing.  My modem is a
$USR Courier HST dual standard.
$My problem:
$When transferring files at high rates (9600, 14400), I encounter
$frequent errors (like every other block) using ymodem or xmodem.
$A friend told me that the disk cacheing is to blame because interrupts
$are disabled while the cacheing is being executed and at high bit rates
$I'm probably missing characters.

   I would doubt that this is true ... your friend is correct that under
certain circumstances, disk caching can cause high-speed modem connections
to drop characters.  However, the circumstance under which this happens is
the use of extended memory (that's 286/386 memory above 1M, _not_ EMS!) as
a disk cache.  Use of conventional or expanded memory, or a caching disk
controller, should not cause this problem.

   But that's a _should_ not, and you never know what happens in real life.
-- 
Stephen M. Dunn                               cs4g6ag@maccs.dcss.mcmaster.ca
          <std_disclaimer.h> = "\nI'm only an undergraduate!!!\n";
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               I Think I'm Going Bald - Caress of Steel, Rush