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Xref: sserve comp.os.os2.programmer.misc:9526 comp.os.linux.development:8628 comp.os.minix:23628 comp.os.mach:3751 comp.periphs:5412 comp.unix.bsd:13861 comp.unix.pc-clone.32bit:6100 comp.os.386bsd.development:2046 comp.sys.ibm.pc.hardware.misc:4935 Newsgroups: comp.os.os2.programmer.misc,comp.os.linux.development,comp.os.minix,comp.os.mach,comp.periphs,comp.unix.bsd,comp.unix.pc-clone.32bit,comp.os.386bsd.development,comp.sys.ibm.pc.hardware.misc Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!bunyip.cc.uq.oz.au!munnari.oz.au!spool.mu.edu!howland.reston.ans.net!EU.net!Germany.EU.net!ping.de!robkaos!robsch From: robsch@robkaos.ping.de (Robert Schien) Subject: Re: [Announcement] 386BSD Release 1.0 Message-ID: <1994May5.180830.734@robkaos.ping.de> Followup-To: comp.os.os2.programmer.misc,comp.os.linux.development,comp.os.minix,comp.os.mach,comp.periphs,comp.unix.bsd,comp.unix.pc-clone.32bit,comp.os.386bsd.development,comp.sys.ibm.pc.hardware.misc Organization: Private Site, Essen, Germany X-Newsreader: TIN [version 1.2 PL2] References: <jmonroyCp6wpE.7yG@netcom.com> <2q63q2$927@dearg.cuillin.org.uk> <wright.86.000DC700@lims01.lerc.nasa.gov> <2qaeel$d5s@Germany.EU.net> Date: Thu, 5 May 1994 18:08:30 GMT Lines: 26 Bernard Steiner (bs@Germany.EU.net) wrote: : How do you access a SCSI cdrom without any sort of operating system ? This is not the problem. If you boot from a hard drive, you have no OS, too, in the first;) If I understand the boot mechanism correctly, what happens during booting on a PC is that there is a BIOS call issued which loads the very first sector of the hard drive into memory. This first sector contains a short program which loads further parts and so on. The BIOS on the SCSI host adapter translates the booting call of the PC BIOS into SCSI commands which load the very first sector or perhaps even better formulated: the HA BIOS fakes the PC BIOS a 'normal' hard drive, which can be accessed by the PC BIOS as 'usual'. Now it is possible that you add further options to the host adapter BIOS which allows you to select the SCSI ID from which you want to boot. Therefore you could boot from any SCSI device. Of course, it should make sense: how dou you boot from a SCSI printer? :-) But booting from cdrom or tape should be perfectly legal! Of course, many (all?) vendors of SCSI HAs do not support this obvious feature. Or do I see something wrong? Robert