*BSD News Article 29000


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Newsgroups: comp.os.386bsd.development
Path: sserve!newshost.anu.edu.au!munnari.oz.au!ihnp4.ucsd.edu!usc!howland.reston.ans.net!pipex!sunic!EU.net!Germany.EU.net!netmbx.de!zrz.TU-Berlin.DE!fub!obh.in-berlin.de!aeon.in-berlin.de!thomas
From: thomas@aeon.in-berlin.de (Thomas Wolfram)
Subject: Re: DMA bounce-buffers now implemented in FreeBSD-current
Message-ID: <Cnor2s.15w@aeon.in-berlin.de>
Organization: Cities in Dust
X-Newsreader: TIN [version 1.2 PL2]
References: <JKH.94Mar25161128@sentnl.ilo.dec.com> <JKH.94Mar27000401@whisker.hubbard.ie>
Date: Sun, 3 Apr 1994 13:35:15 GMT
Lines: 23

Jordan K. Hubbard (jkh@whisker.hubbard.ie) wrote:
> In article <UWP.94Mar25194257@maelaren.cs.tu-berlin.de> uwp@cs.tu-berlin.de (Udo Wolter) writes:

>    Can anyone describe what DMA bounce buffers exactly do besides of allowing
>    more than 16MB in an ISA machine ?

> That's all they do.  They also allow the usage of ISA controllers in
> EISA machines, or VLB controllers with broken DMA (like the Buslogic
> Bt445S) to work.

Could someone please explain what "broken DMA" of Bt445S means exactly?
Does it mean it acts like a ISA busmaster DMA controller (16MB address
space only) or what?
Is there a list of VLB controllers which have working DMA?

Thank you in advance,
Thomas
-- 
Thomas Wolfram        <thomas@aeon.in-berlin.de>     Germany:   0 30 31421171
PRZ TU Berlin         <wolf@prz.tu-berlin.de>         abroad: +49 30 31421171
EANTC                 WWW:             http://www.prz.tu-berlin.de:2784/~wolf
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