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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.rmit.EDU.AU!news.unimelb.EDU.AU!munnari.OZ.AU!news.mel.connect.com.au!news.mel.aone.net.au!imci4!newsfeed.internetmci.com!news1.erols.com!newsmaster@erols.com From: Ken Bigelow <kbigelow@www.play-hookey.com> Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: Installing DOS on FreeBSD Drive Date: Mon, 10 Jun 1996 20:00:41 -0700 Organization: Erols Internet Services Lines: 44 Message-ID: <31BCE159.251E@www.play-hookey.com> References: <4p7lkn$6vs@tribune.usask.ca> <1996Jun8.045040.9320@cs.mun.ca> <4pe0cm$4s8@uriah.heep.sax.de> <4phj2f$8gr@ns2.ryerson.ca> NNTP-Posting-Host: kenjb05.play-hookey.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 2.02 (Win16; I) John Verne - CNED/F94 wrote: > > J Wunsch (j@uriah.heep.sax.de) said: > *SNIP* > : That's not true. The only requirement is that the _entire_ DOS slice > : must be accessible by the BIOS, while it's sufficient for BSD that > : only the root partition (usually the first part of the BSD slice) > : resides in this area. > > : If your entire disk is accessible to the BIOS, it's absolutely > : irrelevant which system resides where. > > Does this include so-called extended bios'? I have a drive that uses a > software driver to fool with the geometry, but I understand that newer > motherboards don't need this. Is BSDfree and DOS a happy couple if, for > example, I had a 1.2 gig harddrive and wanted to put DOS in a, say, 200M > partition (slice?)? > > I'm planning on making BSDfree my 'boot' OS, but would like to keep > PC-DOS around as a security blanket. > This is almost exactly what I have done with most of my subnet. However, I have always put my DOS partition down first, to occupy the first 255 MB on the drive. I then let FreeBSD have the rest. That way, I keep my DOS clusters down to 4K each (62,444 of them) and still make sure that any BIOS can access all of DOS and the root slice of FreeBSD. It also gives me room to put the FreeBSD source files in the DOS partition for fast installation. One caveat I have discovered: Boot Manager for 2.1R wants the logical disk geometry to have fewer than 1024 cylinders, regardless of what "should" work. If I go in and force the physical disk geometry, FBSD will happily install but Boot Manager won't start it -- just repeats F? when I press F2. However, if I take my Maxtor 2 GB drive (3893 x 16 x 63) or the WD Caviar (4092 x 16 x 63) and let FreeBSD call them 973 (or 1023) x 64 x 63, Boot Manager is perfectly happy and the system flies. (Of course, I loose 1008 blocks -- 1 cylinder -- on the Maxtor because it has an odd number.) I posted a query about why this should be and how to change it to fit the "real" geometry, but haven't yet seen a reply. In the meantime, this is the behavior I have experienced. Ken