*BSD News Article 25157


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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: <jmonroyCI82o0.6Jt@netcom.com>
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
X-Newsreader: TIN [version 1.1 PL8]
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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