Re: stage1_5, How does it work? Plus New Filesystem

[OKUJI Yoshinori]

Shaun, please post your messages to bug-grub.

From: Shaun Savage <address@hidden>
Subject: Re: stage1_5, How does it work? Plus New Filesystem
Date: Fri, 19 Jan 2001 10:28:13 +0100

> Compressed Block Device is a linux kernel driver that does demand
> decompression of the filesystem.  It is not a file system to speak of,
> it is a block device BUT the partition "image" can have the kernel in
> it, the stage2 bootloader, the menu.lst, splash screen, .....   It does
> it own partition managment. this partition has a pseudo file system on
> it where the content are files.
> 
> The CBD is designed for use in embedded devices.  It shrinks the
> filesystem size by 2.5 - 3 times so less storage is needed.

I see the concept. Now I want more specific information.

> For more information see http://www.infomatec.de/cbd

I tried to open the URL, but my browser said:

Not Found

The requested object does not exist on this server. The link you followed is
either outdated, inaccurate, or the server has been instructed not to let you
have it.

> DOES GRUB work like this?
> 
> stage1/MBR  loads stage1_5 from sectors 1 - N
> stage1_5    load a file from the filesystem, "stage2" (for CBD the name
> is "/BOOT")
> stage2            load finds file "menu.lst" ( "/BLST" or "/BMNU" )
> menu.lst    is the booting script 

This explains how GRUB works *usually*, but GRUB is not restricted to
the usage. Strictly speaking, you can put Stage 1.5 (or Stage 2)
anywhere you like, and Stage 2 can load a configuration file from
anywhere on your disks (The configuration file needs not to be put in
a filesystem). See the Programmer Reference Manual in the GRUB manual,
for more details.

> I have attached the CBD files htat I am using.  I also 'hacked' the
> configure.in and Makefile.in and Makefile.am BUT I am not sure I did the
> right things. It works, but it makes the stage2/makefile every time.

You shouldn't modify Makefile.in manually; It's a automatically
generated file with Automake. Anyway, send a patch to the list, and we
will suggest a better way or approve the patch.

Okuji