Arch Linux

Heller_Barde

Member

Registered: 2008-04-01

Posts: 245

Building a kernel without initrd. I am stuck :)

Hi everyone

I am a reasonably experienced Linux user coming from gentoo, thus having done my fair share of compiling my stuff, especially kernels.
I now saw the Blog entry from k.mandla about booting crux in circa 16 seconds. (http://kmandla.wordpress.com/2008/06/08 … with-crux/)

I thought if he can do that on a 550 MHz machine with crux, i can do something similar with my core2duo and archlinux. I started by taking the PKGBUILD (and stuff) from /var/abs/core/kernel26 and modifying it to not generate an initrd. I then started a config from scratch. I think i have all the necessary stuff to at least be able to mount root. (device drivers for my harddisk controller (ata_piix), filesystem support (ext2/3), Block device support)
I ended up turning on all the ata/sata related drivers. still doesn't work. I tried it about 20 times till now. It's getting on my nerves *g*.

Do you have any suggestions what i could be missing, or does anyone know exactly which options you need to boot from Harddisk?

The error i get is the following:

VFS: Cannot open root device "sda3" or unknown-block(0,0)
Please append a correct "root=" boot option; here are the available partitions:
0100      4096 ram0 (driver?)
.
.
.
010f      4096 ram15 (driver?)
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

the fact that my harddisk is not even listed in the "available partitions" tells me that it's driver is not yet compiled into the kernel but that's virtually impossible because i have activated every single driver somehow related to harddisk controllers by now...

I hope someone can tell me what silly mistake i made

Cheers Heller Barde

PS: please no discussion about the why of that little project. its (like most stuff i do on linux) on a "because i can" reasoning

patroclo7

Member

From: Bassano del Grappa, ITALY

Registered: 2006-01-11

Posts: 915

Re: Building a kernel without initrd. I am stuck :)

I would play with the Advanced Partitioning section of the kernel config. In a laptop I have not with me now it was necessary to include some stuff there for a controller supported by ata_piix, otherwise I got that same error. I can not be more precise since the beast is not here

---

Mortuus in anima, curam gero cutis

patroclo7

Member

From: Bassano del Grappa, ITALY

Registered: 2006-01-11

Posts: 915

Re: Building a kernel without initrd. I am stuck :)

Well, I have another laptop with linux here and I think to remember that the relevant setting where you could try to put a Y is:
File Systems --> Partition Types --> Advanced Partition Selection
Then you get a list of supported partition tables/maps. I am not sure which one I needed, perhaps "PC Bios (MSDOS Partition Tables) support.

---

Mortuus in anima, curam gero cutis

Heller_Barde

Member

Registered: 2008-04-01

Posts: 245

Re: Building a kernel without initrd. I am stuck :)

thanks a lot. unfortunately it didn't work (i already had PC Bios (bla) turned on. tried now with all of them turned on. didn't work either...)
what i am going to try now is take an archlinux config and strip it down... will be a lot more work than the other way 'round, but let's see...

cheers Heller Barde

Last edited by Heller_Barde (2008-08-06 14:37:30)

broch

Banned

From: L.A. California

Registered: 2006-11-13

Posts: 975

Re: Building a kernel without initrd. I am stuck :)

I don't have problems with kernel running without initrd.
it looks like you have not build-in disk and fs

I can post my config (for 2.6.26.1 and 2.6.27.rc1-git4) if this would help (nothing special there though)

somedrew

Member

From: Canada

Registered: 2007-05-14

Posts: 140

Re: Building a kernel without initrd. I am stuck :)

Seems disk controller{ish} related. What about booting with the arch kernel and checking all the loaded controller related modules or using hwdetect? You can also post the relevant hardware to get ideas for the .config.

cheers,

bushmannt

Member

From: Charlston, SC

Registered: 2008-08-07

Posts: 7

Website

Re: Building a kernel without initrd. I am stuck :)

it definitely looks like you didnt include the disk driver you need.  make sure you know which disk driver you're using.  it got complicated once sata hit, it used to be easy with eide.

rooloo

Member

Registered: 2008-07-09

Posts: 218

Re: Building a kernel without initrd. I am stuck :)

if you have a sata drive you need enable scsi support. I found that out the hard way one time.

smurnjiff

Member

Registered: 2007-06-25

Posts: 211

Re: Building a kernel without initrd. I am stuck :)

If you're building a new kernel, I recommend 2.6.27-rc2.  I've noticed a bit of performance improvement and it hasn't crashed on me before.

Heller_Barde

Member

Registered: 2008-04-01

Posts: 245

Re: Building a kernel without initrd. I am stuck :)

sry i didn't check back until now. i was busy with exams and whatnot
i still am not sure why it only shows ramdisks as available partitions but i seem to have selected a legacy ide driver and thus my grub entry was wrong, it pointed to sda3 instead of hda3. stupid, stupid, stupid... i have to get through the stupid exams now, I will check back though once i have had time to sit down and configure another kernel again (thx for the tip with 27-rc1 smurnjiff)

cheers Heller Barde