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From: jmonroy@netcom.com (Jesus Monroy Jr)
Subject: Re: [FreeBSD 1.0R] DMA Problems?
Message-ID: <jmonroyCI82o0.6Jt@netcom.com>
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
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References: <2eta3j$6t9@vixen.cso.uiuc.edu>
Date: Sat, 18 Dec 1993 08:38:23 GMT
Lines: 58
Rafal Boni (rkb55989@uxa.cso.uiuc.edu) wrote:
: jmonroy@netcom.com (Jesus Monroy Jr) writes:
: >Rafal Boni (rkb55989@uxa.cso.uiuc.edu) wrote:
: >: j@uriah.sax.de (J Wunsch) writes:
: >: [stuff J"org and Terry were debating deleted...]
: >: >In fact, i'm also experiencing lotta DMA overruns when attempting to do
: >: >some floppy IO while some heavy compile job is running. This is in a box
: >: >with an Adaptec SCSI, and i didn't track it down whether it's the CPU
: >: >load that causes the trouble (would really look strange to me), or if
: >: >it's the heavy disk IO that happens while compiling.
: >: I would be tempted to say that the Adaptec is at fault... I have a
: >: 3Com 3c507 Ethernet card in my machine, and the docs SPECIFICALLY
: >: mention the fact that Adaptec's 154x may cause problems for the
: >: Ethernet card's DMA reads/writes.... Later 3Com updated some of
: >: the [I would guess] DMA related circuitry to be able to handle longer
: >: timeouts or something of that nature...
: >:
: > Most problems encountered with Adaptec's 154X and ethernet
: > cards are I/O port, IRQ and DMA channel conflicts.
: > Both 3Com cards and Adaptec's card are configurable to many
: > setting. Getting them to conflict is very easy. I would
: > not be so quick to blame the AHA card.
: FTP to ftp.3com.com and you too can read 3Com's tech notes on the
: subject... While it may not be 100% Adaptec's fault [in this case,
: 3Com relaxed their own timing reqirements to allow both of the
: cards to work], it definitely is something that was caused by the
: Adaptec's holding on to the bus for too long...
:
While I heard your reasoning before from other people, I might
believe it's true if I had some real information.
I spent about 2 minutes on the ftp.3com.com when I realized
that my search was real silly. In the past when a technical
question came about I was willing to state evidence with
references. Namely, I give names, dates, publishers, etc.
If your claim is correct, and I am not saying it is not, then
please site a reference with the exact name and numbers as they
apply.
"Looking in the dictionary for mispelled words is not my idea"
of a valid search either.
--
Jesus Monroy Jr jmonroy@netcom.com
Zebra Research
/386BSD/device-drivers /fd /qic /clock /documentation
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