From owner-freebsd-hackers Wed Feb 7 05:58:18 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id FAA00196 for hackers-outgoing; Wed, 7 Feb 1996 05:58:18 -0800 (PST) Received: from hda.hda.com (hda.com [199.232.40.182]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id FAA00179 for ; Wed, 7 Feb 1996 05:57:35 -0800 (PST) Received: (from dufault@localhost) by hda.hda.com (8.6.11/8.6.9) id JAA25789; Wed, 7 Feb 1996 09:00:14 -0500 From: Peter Dufault Message-Id: <199602071400.JAA25789@hda.hda.com> Subject: Re: PCI programming To: julian@ref.tfs.com (Julian Elischer) Date: Wed, 7 Feb 1996 09:00:13 -0500 (EST) Cc: hasty@rah.star-gate.com, fwmiller@cs.UMD.EDU, hackers@FreeBSD.ORG In-Reply-To: <199602070211.SAA01772@ref.tfs.com> from "Julian Elischer" at Feb 6, 96 06:11:24 pm X-Mailer: ELM [version 2.4 PL24] Content-Type: text Sender: owner-hackers@FreeBSD.ORG Precedence: bulk We forwarded this gentleman's private e-mail to the list. In general we ought to avoid this, and invite the originator to send to the list himself. > Both these devices are Bus Masters.. > neither contains accessible ram. > you can't really pass data directly from one master to another. > > you need a RAM scratch pad that both devices can access. A while back I set it up to DMA directly from a VME disk array controller directly out a high speed multidrop card to an HDTV frame buffer. The disk array controller was set up to generate non-ascending addresses. I suspect the NCR PCI SCSI controller can do the same sort of thing since the NCR 725 can be set up that way, and a network card with a PCI visible FIFO could be the DMA target. However, I know beans about network protocols, whether either card exists, or how you'd want to hook the disk data in through the file system - you'd want direct I/O. -- Peter Dufault Real-Time Machine Control and Simulation HD Associates, Inc. Voice: 508 433 6936 dufault@hda.com Fax: 508 433 5267