Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!utastro!bigtex!james
From: james@bigtex.cactus.org (James Van Artsdalen)
Newsgroups: comp.sys.ibm.pc
Subject: Re: DMA from memory to an DOS file
Message-ID: <14503@bigtex.cactus.org>
Date: 3 Mar 89 04:44:20 GMT
References: <15182@cup.portal.com>
Reply-To: james@bigtex.cactus.org (James Van Artsdalen)
Distribution: usa
Organization: Institute of Applied Cosmology, Austin TX
Lines: 12

In <15182@cup.portal.com>, DeadHead@cup.portal.com (Bruce M Ong) wrote:

> 	I am working on a pc-interface project which accumulates a lot of
> data really fast in a ram buffer (DS:offset to DS:FFFF). I need to write
> this buffer to an opened DOS file using DMA.

Most AT disk controllers don't support DMA.  That's because DMA is
slower than programmed I/O on the IBM architecture.  It's faster to
use "rep outsw".
-- 
James R. Van Artsdalen          james@bigtex.cactus.org   "Live Free or Die"
DCC Corporation     9505 Arboretum Blvd Austin TX 78759         512-338-8789