From owner-freebsd-hackers Fri Nov 6 08:19:23 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id IAA18326 for freebsd-hackers-outgoing; Fri, 6 Nov 1998 08:19:23 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from st-lcremean.tidalwave.net (st-lcremean.tidalwave.net [208.213.203.186]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id IAA18320 for ; Fri, 6 Nov 1998 08:19:18 -0800 (PST) (envelope-from lee@st-lcremean.tidalwave.net) Received: (from lee@localhost) by st-lcremean.tidalwave.net (8.9.1/8.8.8) id LAA03379; Fri, 6 Nov 1998 11:19:05 -0500 (EST) (envelope-from lee) Message-ID: <19981106111905.A3375@tidalwave.net> Date: Fri, 6 Nov 1998 11:19:05 -0500 From: Lee Cremeans To: "Ron G. Minnich" , lcremean@tidalwave.net Cc: hackers@FreeBSD.ORG Subject: Re: Coprocessor board--which I/O method should I use? Reply-To: lcremean@tidalwave.net References: <19981106083018.B2926@tidalwave.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.93.2i In-Reply-To: ; from Ron G. Minnich on Fri, Nov 06, 1998 at 09:41:12AM -0500 X-OS: FreeBSD 3.0-CURRENT X-Evil: microsoft.com Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Fri, Nov 06, 1998 at 09:41:12AM -0500, Ron G. Minnich wrote: > > On Fri, 6 Nov 1998, Lee Cremeans wrote: > > The chip itself can handle 27 MBytes/s in single DES, 10 Mbytes/s in triple > > DES. THere's a data sheet for it if you want to see it; go look at > > www.hifn.com, it's the 7751. > > Right so what I'm saying is this: PII and other Intel-based motherboards > can only do PCI reads at 7 Mbytes/second. Intel bridges don't support > burst mode reads from the processor to PCI, even in cacheable space. So, > if you want to get that bandwidth from the board to main memory you're > going to have to have the board do PCI writes in DMA mode. This sort of > thing slightly complicates user-mode access. Exactly; in fact, DMA mode is the only one supported for actual work on this board. -- Lee Cremeans -- Manassas, VA, USA (WakkyMouse on DALnet and WTnet) A! JW223 YWD+++^ri P&B++ SL+++^i GDF B&M KK--i MD+++i P++ I++++ Did $++ E5/10/70/3c/73ac/95/96 H2 PonPippi Ay77 M | mailto:lcremean@tidalwave.net http://st-lcremean.tidalwave.net | Powered by FreeBSD 3.0-CURRENT To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message