From owner-freebsd-hackers Tue Dec 16 20:09:14 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id UAA04091 for hackers-outgoing; Tue, 16 Dec 1997 20:09:14 -0800 (PST) (envelope-from owner-freebsd-hackers) Received: from ns2.cetlink.net (root@ns2.cetlink.net [209.54.54.20]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id UAA04069 for ; Tue, 16 Dec 1997 20:09:04 -0800 (PST) (envelope-from jak@cetlink.net) Received: from hot1.auctionfever.com (ts1-cltnc-13.cetlink.net [209.54.58.13]) by ns2.cetlink.net (8.8.5/8.8.5) with SMTP id XAA17829; Tue, 16 Dec 1997 23:08:38 -0500 (EST) From: jak@cetlink.net (John Kelly) To: Mike Smith Cc: FreeBSD Hackers Subject: Re: 3com 3c509 card Date: Wed, 17 Dec 1997 05:09:35 GMT Message-ID: <349a59c3.99678713@mail.cetlink.net> References: <199712170334.OAA01300@word.smith.net.au> In-Reply-To: <199712170334.OAA01300@word.smith.net.au> X-Mailer: Forte Agent 1.01/16.397 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by hub.freebsd.org id UAA04070 Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk On Wed, 17 Dec 1997 14:04:26 +1030, Mike Smith wrote: >"AT Bus Design" (Edward Solari, Annabooks) BTW, I checked on getting that book and it seems to be no longer available. >Now, if you take into account just a little CPU overhead, interrupt >cycle overhead, metadata overhead, you will quickly see that you're >not going to route 4MB/sec aggregate traffic through anything on the ISA >bus, period. I seem to have one 486 board running at 12 MHz ISA and clock doubled 50/100MHz DX4-100 CPU will no apparent problems. This has reduced my (measured) 8 bit I/O cycle time to 0.65 usec. I don't have a suitable method for measuring the 16-bit cycle time, but I'm hoping for nearly 4MB through this supercharged bus in 16-bit mode. I'm only getting about 700K per card, so I don't think I need a full 4MB anyway. I might even be able to use five interfaces -- they won't be saturated all the time. >Personally, I'd recommend a 4-port Zynx card. I have a small truckload of SMC Ultras I need to use. John