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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.ecn.uoknor.edu!news.wildstar.net!newsfeed.direct.ca!op.net!news.mathworks.com!fu-berlin.de!irz401!orion.sax.de!uriah.heep!news From: j@uriah.heep.sax.de (J Wunsch) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: how can I boot from "live CDROM"? Date: 3 Jan 1997 21:05:56 GMT Organization: Private BSD site, Dresden Lines: 30 Message-ID: <5ajsbk$fnk@uriah.heep.sax.de> References: <32BECE33.15FB@math.tau.ac.il> <59ofu8$brm@uriah.heep.sax.de> <5a9e21$huj@uriah.heep.sax.de> <32C8BCC0.4ECD@mcil.comm.mot.com> <5ahubk$h62@raven.eva.net> 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 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:33586 jca@bighorn.accessnv.com (J.C. Archambeau) wrote: > You can boot from SCSI CD-ROMs that allow you to boot from any SCSI ID. > Starting with the Adaptec AHA-1542C and the 2940s, you can select what > SCSI ID is your boot device when booting from SCSI. Some system BIOS > vendors are adding the option of booting from CD-ROM in the near > future. However, the ``real life way'' of booting a CD has been made differently. No, while we (Unix guys) would perhaps think most about the matter that CD-ROMs are 2 KB blocked, while most magnetic disks are 512 byte blocked, our friends from Dossyland suffer from a totally different problem: their systems assume that they are booted from either drive A: or drive C:. Hence the `El Torito' bootable CD-ROM specifications go _great lengths_ into hairy details about what they call ``emulation booting'', with shifting disk numbers in the BIOS, and some other fairly ugly stuff. From a Unix point of view, you can take the `El Torito' specs, rip off 75 %, and get flying with the rest (what they call ``non-emulation booting''). The sad things is that it's becoming a standard, so when preparing a bootable CD-ROM, you can't simply ignore that crap, but gotta deal with it. -- 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. ;-)