[9fans] new bootstrap structure

[9fans] new bootstrap structure

[anothy]

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// How much target h/w has a CD-drive and a
// BIOS that supports CD-boot?

i believe most systems made within the past few
years meet this requirement. maybe not "most"
(i don't really know the numbers), but it certainly
doesn't seem rare.

// Looks like it's getting time to upgrade.

in the case of a cd-based install, i'd still hope for
(and kinda expect) an optional floppy that'll get
things up enough to find the "real" kernel on the
CD. the benefit here is that you'd not need any
network or vga drivers on that small floppy.

i know i'd hope for this, at least, as i still
occasionally want to install Plan 9 on older boxes.

what to do for people without CD drives is a
seperate question.
ア


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From: "Chris Hollis-Locke" <chris@cjl1.demon.co.uk>
To: <9fans@cse.psu.edu>
Subject: Re: [9fans] one reason ideas from Plan 9 didn't catch on
Date: Tue, 13 Nov 2001 23:27:53 -0000
Message-ID: <006f01c16c9a$d20e4b00$2248dec2@falken>

How much target h/w has a CD-drive and a BIOS
that supports CD-boot?
I know mine doesn't!

Looks like it's getting time to upgrade.

Re: [9fans] new bootstrap structure

[George Michaelson]

As I understand it, the El-Torrito method used by BSD releases
depends on a facet of the CD standard which lets the CD act as
a 2.88Mb floppy via a CD-FS pointer to a specific file in the
real IS09660 CD dataset.

This file is usually exposed in the FS as a <imagename>.flp file
so you can in BSD terms mount it as a virtual device and look in
it.

More to the point, you can write it (or more plausibly the 1.44mb
variants) to a floppy via  rawrite command, from a mounted CD in
any operating system which reads ISO9660 format CDs.

So the kit doesn't need to ship a floppy, it just needs to expose
the file which is the boot image, or a variant of it, and tell
the user to mount the CD in Windows, and use a rawriter method
to copy the boot image to a floppy, and then reboot off that floppy.

in the FreeBSD releases, this is the dataset /floppies in the root of
the CD.

I used this to cut my own FreeBSD install image, which required making
floppy images, copying to /tmp, vnconfig mounting as virtual devices,
copying the kernel, then writing into the kernel image the memory-mapped
FS image of the root with the modified sysinstall script, then writing
the modified kernel back to the vnconfig mount of the floppy image, then
re-making the .ISO image with that floppy .flp file as the boot disk
pointer, and burning to CD. I know it sounds tortuous but each stage was
rational, and simple.

I am sure a Plan9 install modification process would be simpler btw.

cheers
	-George

RE: [9fans] new bootstrap structure

[Jason Gurtz]

> what to do for people without CD drives is a
> seperate question.

  I'm not sure how many people around here have played much with the grub bootloader.  It supports quite a few "standardish" Ethernet adapters as well as built in support for reading FAT and other file systems.  This comes in handy as grub features a built in (very) mini shell not entirely unlike what the PROM offers in a RISC box.  The hapless admin can hand boot an OS from any of the recognized file systems. The version I've built for booting GNU/Linux weighs in <115K.  It might be a bit more than Plan 9 needs but it could be a good source of ideas.  Find it here:  http://www.gnu.org/software/grub/ 

  I few days ago I did an ftp install of FreeBSD 4.4-RELEASE.  It's pretty smooth; one downloads 2 1.44 Meg floppy images, dd them to disks (gah, 5 out of 7 were ready for the bin) and boot.  The rest of it was fairly intuitive to me save for that it's not immediately clear when you are done.  There was no wording to suggest that indeed all tasks were complete and I should reboot now.  Other than that I had my cake and ate it too  :)  I would consider it close to a model install process.

P.S.  Don't be afraid of the GNU people calling it alpha software.  It has yet to fail me in several situations.  But maybe better programmers like yourselves would have a clearer view of whether to be afraid or not  ;)

Cheers,

~Jason

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Re: [9fans] new bootstrap structure

[plan9]

On Wed, Nov 14, 2001 at 11:33:55AM -0500, Jason Gurtz wrote:
>   I'm not sure how many people around here have played much with the grub
> bootloader.  It supports quite a few "standardish" Ethernet adapters as
> well as built in support for reading FAT and other file systems.

Having hand-crafted a hard disk boot sector from an install floppy image
only to find I had to bung in the LBA of the root directory into the volume
id, I'd appreciate a boot loader that understood FAT a little better.

(I was installing Plan 9 on a Linux laptop with a busted floppy and no
CD-ROM.  I made a FAT filesystem on the swap partition, mounted the floppy
image, copied the files over, copied the boot code from the floppy image
into the boot sector, patched the root dir's LBA into the volume id, added
the swap partition to LILO, and Bob's my uncle.)