Boot manager behavior questions

Michael Dexter dexter at
Sat Aug 6 21:22:35 GMT 2005

Hello all,

I am practicing x86 5.4-REL disaster recovery and perhaps someone 
intimate with the boot manager (perhaps "boot2") could kindly explain 
a few things.

Yes, I have attempted to answer these by reading: 

(BTW, why does only the "recent" list traffic search option seem to 
give results as apposed to "all?" I'm sure these have been asked in 
one form or another but only recent results were given from the 
search page. ( 
"recent" would be in "all," right?))

I have also read boot(8) recent discussion on "editing the boot menu" 
and notably "Boot manager question" that appears to have gone 
unanswered. I will rephrase it for the sake for the original author:

1. Is there any equivalent to nextboot(8) for the boot manager such 
that a boot selection can be made prior to the boot sequence so that 
the choice can be made remotely instead of only at the console?

2. Can anyone confirm that the "Default" behavior is simply F1 (first 
slice) the first time it is invoked and then any other choices become 
the next default?

That assumption comes from the fact that if / is placed on its own 
second or higher bios slice/"primary partition," the boot manager 
fails to find it "Invalid partition" but will work if the appropriate 
F* is typed, such as F4 (if on the forth slice).

No problem. I know for a fact that I want to boot from ad0s4a, my 
valid / slice and partition and I trust that F4 is choosing that 
which allows it to boot.

However, I should be able to manually choose that at the "boot:" 
prompt. The "Invalid partition" error kindly gives me the suggestion:

Default: 0:ad(0,a)/kernel

...and the boot(8) page gives this notation:

bios_drive:interface(unit,[slice,]part) filename [-aCcDdghmnPprsv]

In theory, this should work and be the equivalent of choosing F4, right?:

boot: 0:ad(0,4,a)/kernel

BIOS drive 0, ata drive 0, slice 4, partition a, 5.x default boot of /kernel

Alas, it only bells at me and gives me the same suggested syntax.

3. Any idea what I'm doing wrong there? ("install grub" is not the 
answer I have in mind. :) And actually, I was using GRUB and booted 
to a live cd that seems to have had a valid grub.conf which GRUB 
automagically copied to the MBR, rendering the system unbootable.)

4. Related, I see that boot(8) mentions a "-C" "boot from CDROM" 
option, suggesting that say, if your bios isn't configured to boot to 
CD rom first, you could choose to do so from the boot manager. My 
wild guess is:

1:ad(0,a)/kernel -C (CD as second BIOS drive? I don't believe 
acd(0... is a valid option.

Does anyone know the syntax to perform the boot-to-cd from the boot 
manager feat?

Lastly, are is there a command to pop directly into the boot prompt 
the way the space bar will get to the loader prompt so that the 
system doesn't automatically boot on you? Are F1-F* plus "enter" the 
only valid commands at the very beginning?

Many thanks,


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