Re: bootable disk: how?

[buhrow%lothlorien.nfbcal.org@localhost (Brian Buhrow)]

        Hello.  Having recently felt your pain, I can offer a couple of
suggestions.

        Normally, I use the routine
fdisk -c /usr/mdec/mbr /dev/rwd0d
or the d partition of which ever disk I'm working on.
Then, 
fdisk -a /dev/rwd0d
to insure the active partition is the correct one.

Be sure to check and make sure the disklabel and partition tables agree on
which sector the 'a' partition begins.

Next, I do:
cd /usr/mdec
installboot -v -o <options, usually console> /dev/rwd0a bootxx_ffsv1
, since I usually boot from ffsv1 filesystems.

This sets up the partition boot record on the 'a partition, but you know
that. :)

Finally, the one which has tripped me up most recently, is to check and
make sure you have a modern copy of /usr/mdec/boot in the /boot file of the
filesystem you're booting from.  Without this, even with all of those steps
above, you'll get the kinds of error messages you're seeing.
        The reason you want a newish copy of this file is because I've found
that bioses have changed over time, and as I've moved disks from machine to
machine, I've neded what ever magic exists in the newer boot file.
Normally, I'm paranoid and don't touch this file, since it's so critical to
booting.  But, that has bitten me in the proverbial backside on at least
three occasions in the last six months.
        So, since it sounds like you've checked all the other pieces of this
admittedly confusing puzzle, I'd check the /boot file and make sure it's
from at least NetBSD-3.x.

        If that doesn't fix it, insure that you and BIOS agree on which disk
is disk 0.  I've found on some machines, NetBSD and the bios differ wildly
on which disk is wd0, and, consequently, I've been administering to a disk
that the bios doesn't give a wit about.  The machine from which I'm writing
this message, for example, boots from one of its raided disks, the one of
which is a detail of which I am totally ignorant.  My solution? make all of
them bootable and all works as I expect.  This has the side effect of
allowing me to boot when one of the disks dies, either because the bios is
smart enough to try the next disk, or because I  can move disks around in
the machine until it boots again.

        I hope these ramblings help you get on your OS again.
-Brian

On Apr 17,  1:24pm, der Mouse wrote:
} Subject: bootable disk: how?
} Okay, I give up.  What does it take to make a disk bootable?
} 
} I thought I knew.  But either I'm wrong or the tools aren't doing what
} I thought they were (and, if I'm reading things right, what they're
} documented as).
} 
} I've used fdisk -aui and answered y to the "update the bootcode"
} prompt.  I've used installboot to update the second-level bootlocks.
} I've even tried disklabel -B (this started on a 3.0 system).  Nothing
} works.
} 
} Most recently, I moved the disk to a 4.0 machine and used fdisk -aui
} and installboot there.  It *still* fails to find an OS.  (The exact
} message differs from system to system, depending on the BIOS; the 4.0
} machine says "DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER",
} while the 3.0 machine says "Operating System not found".  Of course, I
} have to either unplug other disks or disable booting from them, or the
} machine boots normally from wd0 (3.0) or sd0 (4.0).)
} 
} fdisk (4.0) shows
} 
} Partition table:
} 0: NetBSD (sysid 169)
}     start 63, size 8448237 (4125 MB, Cyls 0-525/224/63), Active
} 1: <UNUSED>
} 2: <UNUSED>
} 3: <UNUSED>
} Bootselector disabled.
} 
} disklabel (4.0) says
} 
} #        size    offset     fstype [fsize bsize cpg/sgs]
}  a:   8448237        63     4.2BSD   2048 16384 26296  # (Cyl.      0*-   
8939)
}  c:   8448237        63     unused      0     0        # (Cyl.      0*-   
8939)
}  d:   8448300         0     unused      0     0        # (Cyl.      0 -   
8939)
} 
} The disk is (again, 4.0)
} 
} pci0 at mainbus0 bus 0: configuration mode 1
} pci0: i/o space, memory space enabled, rd/line, rd/mult, wr/inv ok
} piixide0 at pci0 dev 7 function 1
} piixide0: Intel 82371AB IDE controller (PIIX4) (rev. 0x01)
} piixide0: bus-master DMA support present
} piixide0: primary channel wired to compatibility mode
} piixide0: primary channel interrupting at irq 14
} atabus0 at piixide0 channel 0
} wd0 at atabus0 drive 1: <FUJITSU MPD3043AT>
} wd0: drive supports 16-sector PIO transfers, LBA addressing
} wd0: 4125 MB, 8940 cyl, 15 head, 63 sec, 512 bytes/sect x 8448300 sectors
} wd0: 32-bit data port
} wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 4 (Ultra/66)
} wd0(piixide0:0:1): using PIO mode 4, Ultra-DMA mode 2 (Ultra/33) (using DMA)
} 
} The disk works fine for non-boot purposes; the only symptom I have is
} this inability to get the BIOS to boot from it.
} 
} I'd even welcome RTFM responses, provided they say which FM to R; I've
} read through manpages over and over again, but of course am not immune
} to missing things.
} 
} /~\ The ASCII                         der Mouse
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