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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.mel.connect.com.au!munnari.OZ.AU!news.hawaii.edu!ames!agate!howland.reston.ans.net!swrinde!newsfeed.internetmci.com!news.mathworks.com!fu-berlin.de!cs.tu-berlin.de!uni-erlangen.de!news.tu-chemnitz.de!irz401!uriah.heep!news From: j@uriah.heep.sax.de (J Wunsch) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: Problems Installing FreeBSD Date: 8 Mar 1996 22:24:35 GMT Organization: Private BSD site, Dresden Lines: 90 Message-ID: <4hqc33$msn@uriah.heep.sax.de> References: <313E10DB.1177@ksu.ksu.edu> Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) NNTP-Posting-Host: localhost.heep.sax.de Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Newsreader: knews 0.9.3 Master Of Past And Present <raistln@ksu.ksu.edu> writes: > I have installed FreeBSD on my system, but it won't boot up when I > reboot the system and use the boot manager. Geometry problems? Just in case, you can hand-fiddle the MBR if you're advanterous. Here's an earlier explanation of mine: Subject: Re: SCSI Question To: hackers@freebsd.org, questions@freebsd.org Date: Mon, 29 Jan 1996 00:57:41 +0100 (MET) Cc: sbqadm@sbq.org.br Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) In-Reply-To: <199601281950.LAA27544@freefall.freebsd.org> from "Justin T. Gibbs" at Jan 28, 96 11:50:52 am X-Phone: +49-351-2012 669 X-Mailer: ELM [version 2.4 PL23] MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Content-Length: 3123 As Justin T. Gibbs wrote: > > >We can't stop the server (4) and it is running this way, I would > >like very much to correct the problem without reinstalling it. > > You'll have to in order to correct the problem. Well, you don't really _need_ to re-install, but it's highly recommended, and you need a double-net if you wanna correct it ``on the fly''. Basically, what happens is the following: |<--------------------------->| | Last | size of a cylinder as the | | ficticous | FreeBSD installation ass- | | cylinder | umed the BIOS would use | | boundary V V V +-+--------------+------------+---------------------- ... ---+-------+ |M| Padded unuse|d space, to |FBSD | un- | |B| remain compa|tible with |boot FreeBSD | used | |R| other system|s | | | +-+--------------+------------+---------------------- ... ---+-------+ ^ ^ | size of a cyl- | | inder as your | | BIOS thinks | |<-------------->| The BIOS is told to boot off cylinder 1, sector 1, head 0. As you can see above, if the ideas of FreeBSD's sysinstall and the BIOS about the size of a (ficticous) cylinder disagree, the Master Boot Record won't find the boot sector of the operating system, and since it misses the boot signature (0x55, 0xaa in the last two bytes of the first sector of the o/s), it prints this ``Missing operating system'' message. However, everything above marked as ``FreeBSD'' is intact, as you can observe when booting from floppy. So if you really don't mind the potential danger, you could re-calculate the values in the MBR to match the C/H/S number for the area where ``FBSD boot'' starts. This way, the MBR will finally find the system. Alternatively, for people like you who are operating a truly dedicated server machine, where the disks will never see any other system so compatibility is not an issue (nor is ``multi-boot''), this is what the ``Dangerously dedicated'' mode is for. Select A)ll FreeBSD in the partition editor, and answer the next question with the non-standard answer ``No''. (Read carefully.) This will setup the following: +-----------------------------------------------------... -----------+ |FBSD | |boot FreeBSD | | | +---------------------------------------------------- ... -----------+ As you can see, no wasted space at all, and since the Master Boot Record and the FreeBSD bootstrap are identical, you don't have to care for any BIOS geometry at all. The BIOS boots sector 1, cylinder 0, head 0, and boots straight into FreeBSD this way. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)