Subject: Re: Bootable CDs
To: <>
From: Simon Burge <>
List: port-alpha
Date: 09/18/1999 13:56:52
[[ background for Alpha folk - there's been a little talk on port-pmax
   about bootable CDs for the pmax - Ross Harvey has noted that the
   pmax doesn't currently support bootable iso9660 CDs, only ffs
   CDs. ]]

Simon Burge wrote:

> Simon Burge wrote:
> > From the looks of things, alpha needs the last 32 bytes of the first
> > sector (with a valid checksum).  I think the pmax needs 24 bytes
> > starting at byte 8 - the rest of the first sector doesn't matter.  You
> > mention sparc as a sector-0 dependant arch - do you know what it needs
> > and if there are any others that need sector zero?
> Thinking about this a little more - at the moment the pmax stuff assumes
> that the first stage is in the remainder of the the first 8kBytes of
> the disk, and it looks like the Alpha does too.  One idea that comes to
> mind it to allow installboot to take an offset into the disk where stage
> one is located.  Then on a CD, you could have the iso9660 filesystem
> finishing at some certain offset before the end of the CD and either the
> pmax or alpha stage one (or possible both if some other architectures
> want stuff in the first 8 sectors) after the iso9660 filesystem.

Even on an iso9660 CD, it appears that the Alpha looks for the second
stage in /boot - this will be yet another conflict.  Ultrix uses
/ultrixboot for the second stage - I'm wondering if it might not be
better to use something like /pmaxboot and /alphaboot for the second
stage bootstraps?