Date: Fri, 01 Dec 2000 15:00:34 +0100 From: "Jose M. Alcaide" <jose@we.lc.ehu.es> To: Robert Nordier <rnordier@nordier.com> Cc: stable@FreeBSD.ORG Subject: Re: The trouble with boot0 Message-ID: <3A27AF02.423BED40@we.lc.ehu.es> References: <200012010836.eB18aMq02131@nordier.com>
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Robert Nordier wrote: > > Are you sure that block 3997224 actually has a boot block on it? > I'd suggest using a utility, or writing a trivial program to access > the whole disk slice and verify that. When I set up a lot of > multiple FreeBSD partitions, I found sysinstall tended to be confused > by them and didn't always install stuff in the right places. Yes, ad0s3 has a boot block. In fact I used a "disklabel -B ad0s3" command. I did a hexdump of /dev/ad0s2 and /dev/ad0s3 and they begin with the same data. > To decide when boot0 or something else is at fault: you should be > able to boot by pressing F2 and then tell /boot/loader to boot from > the third slice. If you can't do that, the problem is not due to > boot0. I got the loader prompt after booting from ad0s2, and I defined both currdev and rootdev to "disk1s3a:", unloaded/loaded the kernel and booted with no problems the system installed in ad0s3. I did another test: I deleted the ad0s1 entry from the partition table and replaced it by a replica of the ad0s3 entry: # flag start chs type end chs offset size 1 0x00 721: 0: 1 0xa5 1023: 87:63 3997224 4418568 2 0x80 1023:255:63 0xa5 1023: 87:63 8415792 8421336 3 0x00 721: 0: 1 0xa5 1023: 87:63 3997224 4418568 Now, pressing F1 or F3 beeps. Only F2 continues to work. If this a geometry problem, I cannot understand why boot0 cannot boot from ad0s3 while there are no problems for booting from ad0s2, which is placed after ad0s3 and beyond the cylinder 1023. I am more interested on an explanation for this problem than on finding the solution. I found this problem while doing a demo for the students of the installation procedure of FreeBSD, so that I would like to be able to explain clearly the reason of the boot failure to them. Thanks, -- JMA ****** Jose M. Alcaide // jose@we.lc.ehu.es // jmas@FreeBSD.org ****** ** "Beware of Programmers who carry screwdrivers" -- Leonard Brandwein ** To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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