Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/5/84; site sunybcs.UUCP
Path: utzoo!watmath!sunybcs!muswiz
From: muswiz@sunybcs.UUCP (Steve Levine)
Newsgroups: net.micro.pc
Subject: dma on pc
Message-ID: <2937@sunybcs.UUCP>
Date: Sat, 15-Mar-86 13:24:27 EST
Article-I.D.: sunybcs.2937
Posted: Sat Mar 15 13:24:27 1986
Date-Received: Sun, 16-Mar-86 08:33:02 EST
Organization: SUNY/Buffalo Computer Science
Lines: 31
Keywords: audio rate dma, pc dma

I am doing digital signal processing with a tms-320-20 card on the
pc.  I have a need to fling blocks of data onto the hard disk while
new audio samples are coming in.  What that means is :

	every 22 microseconds or so (44.1 khz cd format) a 16 bit
	data word will appear in a peripheral card's local ram.  this
	ram can be very big (up to 256k bytes).

	Somehow, I need to shuffle this data from the local ram, out
	to the pc ram (i have a 2 meg talltree ram card in the pc as well)
	eventually, preferably right away, placing the sampled data blocks
	into a contiguous disk file.

	I would like to be able to sample long segments of sound at this 
	sample rate (greater than what can be held in ram) and not have to
	stop the converter.

I figure the problem is one of going around dos calls, possibly writing a
custom assembler routine which tweaks the dma and hard-disk controller, in
order to move blocks of data from memory , directly to the disk.  I know if
the sample-rate was low enough, I could just use dos calls and not miss a
word.

So, does anyone have any knowledge or experience with dma and physical read/
writes of the winchester?   This problem, if solved, opens the way for a lot of
really neat things to happen on the pc (like digital audio storage and other
fun experimental things.).

Anything will help.   Thanks, in advance.

(steve levine alias sunybcs!muswiz)    ihnp4!sunybcs!muswiz