From owner-freebsd-hackers Mon Sep 11 20:13:42 1995 Return-Path: hackers-owner Received: (from majordom@localhost) by freefall.freebsd.org (8.6.12/8.6.6) id UAA18162 for hackers-outgoing; Mon, 11 Sep 1995 20:13:42 -0700 Received: from thumper.osix.com.au (osixsyd.tmx.com.au [203.9.152.143]) by freefall.freebsd.org (8.6.12/8.6.6) with ESMTP id UAA18148 for ; Mon, 11 Sep 1995 20:13:30 -0700 Received: from bruce.osix.com.au (bruce.osix.com.au [203.18.59.4]) by thumper.osix.com.au (8.6.11/8.6.9) with SMTP id MAA16918; Tue, 12 Sep 1995 12:59:19 GMT Message-Id: <199509121259.MAA16918@thumper.osix.com.au> Comments: Authenticated sender is From: "Peter May" Organization: OSIX Pty Ltd To: peter@taronga.com (Peter da Silva), hackers@freebsd.org Date: Tue, 12 Sep 1995 13:12:46 +0000 MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Subject: Re: higher density diskettes Reply-to: peter@osix.com.au Priority: normal X-mailer: Pegasus Mail for Windows (v2.01) Sender: hackers-owner@freebsd.org Precedence: bulk > In article <1337.810473461@critter.tfs.com>, > Poul-Henning Kamp wrote: > >> Microsoft has switched to using so called DMF format > >> (Distribution Media Format - 1,716,224 bytes 1.63 MB) on > >> diskettes for the WIN95 distrubution disks. > > >This is very interesting. If it works for them, we can do that too. > >The changes to the floppy-build procedure is rather few, but I still > >suggest we hang in there until we hear how much trouble MS has with it... > > Anyone know what they're actually doing? > > Amiga uses standard MFM to get 1760KB on the same density disks, by leaving > off the inter-sector gaps and reading and writing a track at a time. If you > also leave off all the sector headers you get 1970KB (you nead one gap/sector > header to mark the beginning of the data, or you'd be all the way to 2000KB). Just think of the buffer size you would need in the FD driver! At least 26k of memory PER TRACK READ. And what about error detection? Are we going to have the driver do CRC checks on data fields as well? That should speed the performance of this already flaky driver up no end! :-) ---------------------------------------------------------------->>>>> Peter May OSIX Pty Ltd Director Level 1, 261-263 Pacific Highway Technical Services North Sydney. NSW. Australia. 2060. Home: +61-18-782858 Internet: peter@osix.com.au Work: +61-2-9922-3999 Fax: +61-2-9922-3385 >>>> PGP Public key available upon request <<<< ---------------------------------------------------------------->>>>>