Compressed Linux Kernel

imad

My understanding is slightly different.

I believe that in the boot block of your machine (the first 512 bytes of what Windows calls the "C" drive) is a boot loader that takes around 446 bytes, followed by the parbreastion table (for the 4 direct parbreastions). The boot loader is a stand-alone program started by the BIOS of your *86 machine when booting up, just after the POST steps. BIOS copies those 512 bytes to 0x7c00 in the RAM and lets it execute.

That loader contains just enough to get the next of several stages of the boot loader and transfers control to it. These, for the GRUB loader, are inboot-grub directory, with a configuration fileboot-grub-grub.conf

None of these are compressed. Here is what is in that directory for my machine:

-boot-grub# ls -l total 186 -rw-r--r-- 1 root root 82 Dec 30 2004 device.map -rw-r--r-- 1 root root 7840 Dec 30 2004 e2fsstage15 -rw-r--r-- 1 root root 7536 Dec 30 2004 fatstage15 -rw-r--r-- 1 root root 6880 Dec 30 2004 ffsstage15 -rw------- 1 root root 767 Mar 16 05:03 grub.conf -rw------- 1 root root 920 Feb 16 16:40 grub.conf.old -rw-r--r-- 1 root root 8448 Dec 30 2004 jfsstage15 -rw-r--r-- 1 root root 7040 Dec 30 2004 minixstage15 -rw-r--r-- 1 root root 9408 Dec 30 2004 reiserfsstage15 -rw-r--r-- 1 root root 11182 Sep 11 2003 splash.xpm.gz -rw-r--r-- 1 root root 512 Dec 30 2004 stage1 -rw-r--r-- 1 root root 106364 Dec 30 2004 stage2 -rw-r--r-- 1 root root 6528 Dec 30 2004 vstafsstage15 -rw-r--r-- 1 root root 9320 Dec 30 2004 xfsstage15

Not all these are used, I do not believe, but surely stage 1 and stage 2 are required, as is grub.conf.

Now the last bit of stage 2 is what will load the actual kernel. Part of that is uncompressed and it uncompresses the rest. So you will find the decompression code in the kernel image, not in the boot loader stuff.

-- .~. Jean-David Beyer Registered Linux User 85642. V PGP-Key: 9A2FC99A Registered Machine 241939. ^^-^^ 08:05:01 up 4 days, 9:16, 3 users, load average: 4.18, 4.20, 4.18