*BSD News Article 25116


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Newsgroups: comp.os.386bsd.development
Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!elroy.jpl.nasa.gov!decwrl!netcomsv!netcom.com!jmonroy
From: jmonroy@netcom.com (Jesus Monroy Jr)
Subject: Re: [FreeBSD 1.0R] DMA Problems?
Message-ID: <jmonroyCI6HqF.Hxu@netcom.com>
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
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References: <2eopau$hde@vixen.cso.uiuc.edu>
Date: Fri, 17 Dec 1993 12:08:39 GMT
Lines: 31

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.  

-- 
Jesus Monroy Jr                                          jmonroy@netcom.com
Zebra Research
/386BSD/device-drivers /fd /qic /clock /documentation
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