Mailinglist Archive: opensuse (2912 mails)

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Re: [SLE] Boot Parameters
  • From: Darryl Gregorash <raven@xxxxxxxxxxxxx>
  • Date: Thu, 10 Feb 2005 02:46:12 -0600
  • Message-id: <420B1F54.8090609@xxxxxxxxxxxxx>
Ted, once again, one reply only please, to the list. And please do stop the editorial commentaries in teh subject line; if they are sincere they are embarrassing for me, while if sarcastic, offensive. I make no judgement.

Ted Hilts wrote:

Darryl
Do I hurry off to learn more about Boot Disks as this is just a "simple" exercise using Grub as some suggest -- one I am too dense to appreciate as others suggest? Or what? I'm too old to go back to school, I'll probably be dead before the next class graduates, if not that then certainly more dense than I am now.

Hope to see some feed back on the list on your considerations as they seem to echo what I want to do and some of the same concerns (valid or invalid). But maybe neither of us appreciate the 'simplicity' when done on GRUB. I'll admit that I can be dense but not just because someone says I am. I am prepared to gather the disk structure and other boot attributes (once I know what to gather) required to do this thing. I know very little about setting up GRUB other than the information in the SuSE reference manual. So maybe I do need to learn more about GRUB, but I'm willing to do that only if I can do this thing, That's what I am trying to determine.

I have too many people contradicting each other here and feel I need a working example that would settle the feasibility of doing this thing. Help is help only when it really helps solve the problem. There is too much of this "Go get lost and read about it at such an such a place". I don't have a trillion years to figure this out. And, I'm not the least interested in finding out WHY I cannot do this thing. That's why I want an example, (at least 2 machines with different OS). Oddly enough and if the issue is so simple, why has no one an example to provide me even though it is a "simple" chore for the boot informed -- which obviously I'm not because it does not seem simple to me -- but then I'm dense.


First off, you get contradicting results because different people interpret your words in different ways. That is not intended as a criticism of your grammatical abilities, but only as a suggestion that sometimes we may need to feel around a bit before we all grasp the correct nature of the problem.

As for the "simplicity" of doing this on GRUB, while I am no expert, I can tell you with some degree of confidence that what I believe you wish to accomplish is either excessively complicated, or trivial and hence meaningless, or impossible.

In reverse order: you cannot possibly have one vanilla boot source that can distinguish between this network card or that, this SCSI device or that, booting from any of a rather long list of possible boot devices, and so on. You cannot possibly have one vanilla boot source that can distinguish between all the different kernels that are installed, or that can anticipate all the variations on where specific directories are mounted (which physical device, that is -- maybe machine A has a separate /boot partition, but B does not). The "generic" solution is thus impossible.

This leaves us with two alternatives. First, you can make every single system bootable, and simply use "chainloader" in the GRUB menu on the boot CD to chain to the MBR of the computer's boot device. This assumes that all systems boot from the same source type, IDE or SCSI or anything else that is allowed doesn't matter, so long as they are all the same. If not, here is where the first potential complication arises: you must now make two or more menu choices, to select chaining to an IDE or SCSI or whatever boot device.

But why bother? Just boot directly from the system itself, hence this solution is trivial and meaningless.

Now we get to the excessive complication. That is what I already suggested, and it is really nothing more than an academic exercise, particularly since you are under time constraints. Yes, it probably can be done along the lines I suggested (but be prepared to have a lot of new coasters for the office trying to get the proper mkisofs commandline), but that would mean a separate boot image, on the CD, for each and every distinct hardware/OS/partitioning combination you have. Each separate boot image means another menu entry, and now you must memorize which menu choice to make for each particular system. If you have any dual-boot systems, now you also require a separate menu item for each distinct configuration and layout for that.

That is why I said I would be reluctant to take on this task for any amount of money -- and I can count pretty high :-)

I hope Patrick's GRUB menu is of some help to you, but do note it is for a single machine, not many. I leave you for now with a quote from Sid's post:

"The more complex you make a setup, the more you impact reliability, simplicity has a lot to recommend it."


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