Subject: Re: status of 'makefs -t cd9660'? (II)
To: Daniel Watt <danwatt@gmail.com>
From: Hubert Feyrer <hubert@feyrer.de>
List: tech-install
Date: 07/08/2005 17:44:49
[I've added tech-install@NetBSD.org again - please CC: it on further
  mails to get status updates there as well!]


On Fri, 8 Jul 2005, Daniel Watt wrote:
> Boot support appears to be working. I have two test suites that I have been 
> using consistently - a Win98 boot floppy to test level1 (8.3) filenames, and 
> my attempt to follow the NetBSD bootable CD guide. I did notice one bug today 
> which I will try and fix tomorrow or this weekend : if the boot image is 
> inside the CD filesystem (ie: if the root of the cd is "/cdsources" and the 
> image is in "/cdsources/bootimages/big-boot.fs"), it shows up with an invalid 
> name on the actual CD. Other than that, I can boot both with my 1.44MB 
> Windows or 2.88MB boot-big.fs. A similar issue right now is that boot images 
> are stored separately on the CD. mkisofs uses a hash table on the inodes to 
> make sure two files (including boot images) are not stored in two places on 
> the CD. However, mkisofs requires that boot images be within the CD's source 
> filesystem. Our tool does not have this limitation, but because of this, if 
> you use a boot image that will be visible from the filesystem of the CD, it 
> will be stored in two places (the boot area and the filesystem area). A hash 
> table feature to resolve this minor design flaw is in the works.

I think it would be acceptable to have the "limitation" that the floppy 
image need to be inside the filesystem of the CD. Of course if that's not 
mandatory that's a bonus.


> I said my attempt at following the NetBSD guide because I am not 100% sure if 
> I have it right. I have only installed NetBSD onto one computer, and that was 
> with a provided NetBSD image.I downloaded the sources from 
> ftp.netbsd.org/pub/NetBSD/NetBSD-2.0.2/i386. I have been calling our tool 
> with i386 as the root of the CD, and installation/floppy/boot-big.fs as the 
> boot image. Is this how it should be done? I have a couple issues with my 
> emulator right now, so I couldnt get the installer to actually partition the 
> emulated hard drive, so I could not adequately test this.

It is how it should be done in (I forgot what the exact name was) the way 
where you put a floppy image on the CD, and boot from that.
The problem there is that this is limited to 1.44/2.88MB.

So in addition to that boot-model that you've implemented, some other one 
will be needed to add, which mkisofs supports with -no-emul-boot. For that 
you put a (small) bootloader somewhere on the CD, which then can load a 
second stage bootloader, which in turn loads the kernel.

This model is what many platforms use for booting NetBSD from CD already, 
and there is a strong desire to move NetBSD/i386 towards that, too.
But this needs support from your tool, so if you could add "no-emul-boot"
mode to your patch for makefs, that would be really good.

For some more information on using the existing (work-in-progress!) 
bootloader for NetBSD/i386, see the posting from Bang Jun-Young (author of 
cdboot) here: 
http://mail-index.netbsd.org/tech-install/2005/06/22/0013.html

More information on directions where this should finally go are linked 
here: http://www.feyrer.de/NetBSD/blog.html#20050628_0233


> Thank you for your patience in letting us finish up our work. There are still 
> a few issues to work out, but it looks like in the next couple of days there 
> will be a version available with improved boot support to enable more 
> testing.

OK! Please post to tech-install@ to get maximum feedback and number of 
(possible :) testers.


  - Hubert