Re: [Bug-grub] Using grub for booting imaged machines

[Jochen Hoenicke]

On Oct 5, Alessandro Rubini wrote:
> 
> There has been no reply to this question. While I offered to document
> stage-1.5, I can't find any information about it, either. Can someone
> please shed some light to help me getting started?

The purpose of stage1_5 is to load stage2 by interpreting the file
system it resides on.  stage1_5 exists because one wants to read as
few sectors as possible from fixed positions.  stage1_5 is very small
and can be embedded in a safe position outside any filesystem, e.g. in
a BSD/reiserfs boot loader area or in the space after the MBR before
the first partition starts.

stage1_5 shares its code with stage2, but it only contains a minimal
subset.  It can only read a single file system and instead of loading
and parsing menu.lst it just loads stage2 and starts it afterwards.
In fact stage1_5 stores the path to stage2 at the same location where
stage2 stores the path to menu.lst.

When you want to use stage1_5, you should embed outside the filesystem
it via the embed command.  Afterwards use the install command, where
you specify the blocklist returned by embed as "STAGE2" parameter and
the location of the real stage2 as "CONFIG_FILE" parameter.

  Jochen