Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!gem.mps.ohio-state.edu!usc!orion.oac.uci.edu!mrichey
From: mrichey@orion.oac.uci.edu (Mike Richey)
Newsgroups: comp.sys.ibm.pc
Subject: Re: DMA controller chip error
Keywords: Fastback, DMA
Message-ID: <3686@orion.cf.uci.edu>
Date: 20 Nov 89 19:21:01 GMT
References: <941@ac.dal.ca>
Reply-To: mrichey@orion.oac.uci.edu (Mike Richey)
Organization: University of California, Irvine
Lines: 36

In article <941@ac.dal.ca> bertfram@ac.dal.ca writes:
>I just bought a copy of Fastback +.  When I configured it the other day
>it informed me that I have an error in my DMA controller chip.  I'm not
>a happy camper.  They suggested that I buy a fix from them.  This is the
>first I've heard of this problem, and it hasn't seemed to affect anything
>in the past.  When I try to run Fastback it tells me that it's going to
>have to run in S-L-O-W mode until I get the problem fixed (yeah, I spent
>$135 on FASTback so it can work in slow mode!!).  Anyway, any and all
>information on this problem (and possible solutions to it) are very
>welcome!!
>
There was once a problem with the 8237 DMA controllers from AMD. The 8237 has
four DMA channels available. Most all applications use only a single DMA
channel to get data to RAM.

What's nice about fastback is that it utilizes two DMA channels to transfer
data. One channel to read from the hard disk, and a second to write to the
floppy. When the hard disk and diskette drive leds are lit, it's not just
because the drives are selected.

Well, fastback makes sure that the hardware is capable of performing. If
you have a faulty 8237, it will detect it. Which it probably has. Now, I
believe that when you install fastback the instuctions say to be sure that
your machine is working in the slowest mode available. In your case be sure
that you're ooperating the system clock at 4.77 Mhz and not 10 Mhz.

The reason it has just showed up now is because you haven't been running any
applications that open more than one DMA channel. Well, I don't know that
you aren't, but I suspect it.

Try re-installing it at 4.77Mhz.

Michael S. Richey
University of California, Irvine - Network & Telecommunications Services
InterNet:   mrichey@orion.oac.uci.edu    BitNet:  MRichey@UCI
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