Strange relation between CentOS and FreeBSD

[saivin]

I had a very strange experience with CentOS. Let me share it with you.

I installed FreeBSD, everything went smooth, I edited my main GRUB to include the following:

title FreeBSD
root (hd0,3,a)
kernel /boot/loader

I rebooted and tried to login to FreeBSD. Gosh..! It wouldn't boot me into FreeBSD! It was just showing:
root (hd0,3,a) with curson blinking for ages...

Although my grub entry was correct, I tried the following :

root (hd0,3)
kernel /boot/loader

root (hd0,3)
chainloader +1

rootnoverify (hd0,3)
chainloader +1

rootnoverify (hd0,3,a)
chainloader +1

Nothing helped.

So, I reinstalled BSD again. Same result.

I thought of getting online help and tried to boot into my CentOS. Would you believe... even CentOS is not booting... Nothing was changed in the GRUB entry. GRUB was not overwritten, neither was my CentOS installation. Then what went wrong with CentOS?

Hesitatingly I tried to log into Debian and thank goodness, it booted me without any fuss. Checked installation manuals of FreeBSD, could not see where did I go wrong.

In one of the mailing-lists somebody had suspected that GRUB may not read UFS2 and its better to use UFS1 for /. Although I suspected this (coz, I'd installed and used FreeBSD 6.2 and since 5.1 release or so, UFS2 is the default), I thought of trying this out and reinstalled FreeBSD with / being UFS1. After installation I rebooted but the same problem. It would just show root (hd0,3,a) and just curson blinking.

All the while CentOS was also not booting. I could have just reformatted FreeBSD partition, but what bothered me was I lost CentOS too. I had done net install and the thought of reinstall everything made me crazy.

I decided to reinstalling FreeBSD one last time and this time, for some strange reason, I stopped at a user warning prompt... it was the disk geometry values... It said a geometry of 232581/16/63 was ok with modern BIOS. If our BIOS was old, make sure the values are not more than 65535/255/63. Until this time I was hitting YES to this prompt. This time however I hit No and I was taken to another prompt. It said the system calculated a value for me and the value was 14593/255/63 and if not satisfied to give my own values. Me...? I laughed and accepted the value it had calculated and went on with installation.

I rebooted the system with my fingers crossed and voila...! the system booted into FreeBSD...! So the bl***y culprit was the disk geometry...??? How on earth a newbie like me would know about disk geometries...

Now, that I could boot into FreeBSD, I thought of chancing with CentOS too. And would you believe it booted into CentOS!!!

Here ends my story and here is the question.

Whats wrong with CentOS? Why did a wrong selection of disk geometry in FreeBSD affect CentOS? Remember, Debian was not affected! Any ideas?

[Rubberman]

As you found, some older bios don't support hard drives with more that 64K cylinders (tracks), so they fudge by changing the number of heads, etc. This is a legacy of early PC's when a big hard drive had 40MB, not 1-2TB. You could update your bios, if possible.

[saivin]

Ya, I can (may be should) update my BIOS. But why did FreeBSD installation problem affect CentOS booting but did not affect Debian?

[Rubberman]

Don't know. Perhaps it misinterpreted the drive geometry in relation to CentOS, but agreed w/ Debian? Since I can't look at your system, I can't say more than that. If you're running new(er) versions of Debian and BSD, remember that CentOS is based on an older kernel and driver set. Did you say which version of CentOS vs Debian vs BSD that you are running?

[rituraj.goswami]

i had a kinda of sameproblem. one of my client needed three os in one hdd. xp, debian and rhel5. so i installed xp then debian and then intalled rhel5. rhe5 didn't detect debian lenny. so i edited but it refused to boot rhel5. xp worked fine. then i formated everythingng and the reinstalled xp then installed rhel5 and then debian.i dont know but something went wrong with the grub which i never understood.

[saivin]

Don't know. Perhaps it misinterpreted the drive geometry in relation to CentOS, but agreed w/ Debian? Since I can't look at your system, I can't say more than that. If you're running new(er) versions of Debian and BSD, remember that CentOS is based on an older kernel and driver set.

Could be.

Did you say which version of CentOS vs Debian vs BSD that you are running?

CentOS 5.3, Debian Lenny, FreeBSD 7.2. (If you wanted the kernel information then I'm not on the machine now.)

[saivin]

i had a kinda of sameproblem. ...
...i dont know but something went wrong with the grub which i never understood.

Some things are never understood I guess... Many a times we keep quite coz, our problem gets solved 'somehow'...

[Rubberman]

Could be.

CentOS 5.3, Debian Lenny, FreeBSD 7.2. (If you wanted the kernel information then I'm not on the machine now.)

I'm using CentOS 5.3 on my workstation also, but instead of dual booting it, I have a pluggable boot drive and several boot discs. Each one has a different OS. The internal drives in the system hold /home so that each Linux or Unix OS can access that volume with source code, user directories, etc. At least with the separate boot drives (containing /boot, /, and swap then I don't have to worry about conflicts like this. Costs more, but is safer.