Date: Wed, 7 Feb 1996 09:00:13 -0500 (EST) From: Peter Dufault <dufault@hda.hda.com> To: julian@ref.tfs.com (Julian Elischer) Cc: hasty@rah.star-gate.com, fwmiller@cs.UMD.EDU, hackers@FreeBSD.ORG Subject: Re: PCI programming Message-ID: <199602071400.JAA25789@hda.hda.com> In-Reply-To: <199602070211.SAA01772@ref.tfs.com> from "Julian Elischer" at Feb 6, 96 06:11:24 pm
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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
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