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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.ecn.uoknor.edu!news.uoknor.edu!news.nodak.edu!netnews1.nwnet.net!news.u.washington.edu!uw-beaver!uhog.mit.edu!news.mathworks.com!fu-berlin.de!zib-berlin.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: Two probs - Boot mgr & cdrom HELP !! Date: 30 Apr 1996 07:15:37 GMT Organization: Private FreeBSD site, Dresden Lines: 35 Message-ID: <4m4emp$5k3@uriah.heep.sax.de> References: <4l01iv$h38@emerald.xara.net> <4lvfan$84@anorak.coverform.lan> 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 0.9.6 brian@awfulhak.demon.co.uk (Brian Somers) writes: >: I have a disk that previously had dos and bsd on it. I now want >: use it for dos/novell but i cannot get rid of the boot mgr ... >Boot DOS and run "fdisk /mbr". It's not documented, but re-writes the >boot sector code. Alternate method: While BSD is still there, use dd if=/dev/zero of=/dev/rwd0 count=100 # IDE dd if=/dev/zero of=/dev/rsd0 count=100 # SCSI This will zero out the first hundred blocks, so any system believes it's got a virgin disk and volunteerely re-installs its own master bootstrap. This is in particular important if you've been using the ``dangerously dedicated'' mode for FreeBSD (one reason why we call it `dangerous'). Otherwise, the following will happen: Dangerously dedicated means the BSD bootstrap (7.5 KB with embedded [faked] fdisk table and BSD label) starts right at block 0, so it's also the master boot record. Now, you replace everything on the disk except the MBR, so this will just leave the first 512 Bytes of BSD's protected-mode loader intact, so the bootstrap will simply fall off the end of sector 0 once it's started... DOS doesn't really like this. :-)) -- 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. ;-)