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Re: AlphaServer DS25 failure

On Tue, Aug 10, 2004 at 09:39:46PM -0700, Steve Langasek wrote:
> On Fri, Aug 06, 2004 at 01:41:49PM -0400, Jay Estabrook wrote:
> > Yes, one could have differently-configured kernels available via aboot
> > "slots" on a single netinst CD/ISO; it's just a matter of building the
> > kernels (as appropriate) and managing them.
> Well, there doesn't seem to be much point in having a kernel listed in
> the aboot config that's only needed on systems that don't support SRM,
> does there?

Indeed... ;-}

> Given that there is no milo support in debian-installer anyway,

It's actually not that hard - there's a MILO "aboot.conf" equivalent
(aptly named "milo.cfg" :-) on the CD in / that has appropriate stuff
in it (find an example attached).

We (HP) actually had it fairly well set up in an unreleased set of ISOs
that were an update to 7.2 for Alpha.

In addition to the /milo.cfg, we had a MILO-configured kernel
(milo.gz) and a common INITRD (I think the latter was custom-built to
contain two sets of modules for the two kernels that might use it).

The MILO kernel booted off the CD was the same kernel that got
installed on the MILO machine (but all SRM machines used a common BOOT
kernel just during installs, and had different one(s) installed).

Only differences between the configs for MILO kernel and SRM UP kernel

	CONFIG_BLK_DEV_RAM_SIZE=12288     # for MILO, big install INITRD image

> I wonder if it wouldn't be better to drop the LEGACY_START_ADDRESS
> option and trade supporting pre-installed MILO-only systems for
> supporting TITAN systems.  Do you have a feel for the relative size
> of the install bases of these two system classes?

IMHO, I'd say the MILO-based machines outnumber the TITAN-based ones
more than 5 to 1, and more likely more than 10 to 1.

So I'd think you'd want to keep/improve the MILO support, if possible...

> If there is a real case for supporting the MILO-only systems, in spite
> of the overwhelming lack of effort to support it for sarge installs,
> then I suppose we would need to talk to the kernel maintainers about
> building two different kernel-images for this case.

It can really be only a matter of adding a single additional kernel to
the (many) already done ones (install/UP/SMP/NUMA/?).

BTW, a MILO install with a properly-prepared CD image amounts to:

1. boot MILO to its prompt
2. type "show" to get it to probe for devices
3. type "sr0:" to get it to "cd" to the SCSI CD device (differs for IDE)
4. type "boot" and you see messages about booting, available kernels, etc.

The milo.cfg file attached at the end provides lots of options such as
graphics and text mode, serial console, rescue, expert mode, and so

So, it's not really that big a deal; critical pieces are:

1. milo.cfg at the root level on the CD
2. a MILO-configured kernel and INITRD

Of course, this all depends on the user having a MILO that properly
supports an INITRD; I believe this should not be an issue, as there
have been such MILOs available for years now, IIRC.

Go for it! :-) :-)


Jay A Estabrook                            HPTC - LINUX support
Hewlett-Packard Company - ZKO2-3/N30       (603) 884-0301
110 Spit Brook Road, Nashua NH 03062       Jay.Estabrook@hp.com
# /etc/milo.cfg
# Global parameters
#	timeout =
#	command = "MILO command"
# Per-image parameters
#	image = [dev:]file
#	label = label
#	root = /dev/<root device>
# 	append = options
# All image descriptions start with 'image' statement
timeout = 300

image = /kernels/milo.gz
label = Install
append = initrd=/images/cdrom.img

image = /kernels/milo.gz
label = InstallText
append = initrd=/images/cdrom.img text

image = /kernels/milo.gz
label = Rescue
append = initrd=/images/cdrom.img rescue

image = /kernels/milo.gz
label = InstallNoProbe
append = initrd=/images/cdrom.img noprobe

image = /kernels/milo.gz
label = InstallExpert
append = initrd=/images/cdrom.img expert

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