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View Full Version : [ubuntu] [SOLVED] error 18: cylinders exceeds maximum supported bios



brojard
December 15th, 2008, 06:08 PM
Back ground:
My old 20 gb hd (ide) on which the OS resided crashed. I have 6 other 120 gb harddrives running raid5. These raided drives do *not* have the OS on them. The previous OS was debian so I thought I'd try ubuntu 10.4 server. I installed a new 80 gig (also ide) harddrive, formated and installed ubuntu 10.4.

I've been setting up services. Raid5 came back fine. Didn't lose anything! Everything is almost completely back to normal. When I left for the day on Friday I shut down. This morning, when I powered it back up it couldn't find the boot image and asked me to insert a disk and hit any key to proceed.

I fiddled around with the bios, changing from *auto* detect to *user* and back several times.... and after a while, grub offered some images to select but: I still get the following:

error 18: cylinders exceeds maximum supported bios.

I fiddled with bios settings again, back to user then to auto, several times... leaving it blank on one occasion and finally it found the boot image.

I shutdown again and rebooted, and same thing again only this time, I had to mess with bios for 2 hours - I don't know why it accepts the changes one time and not another. This seems to be a weird intermittent problem.

Found a thread that says I should copy the partition info C/H/S to bios. How do I do that? What is S? is S Start or is S system?


Results of sfdisk for this device as follows.


sudo sfdisk /dev/sda -l
(I've omitted the end info intentionally)

Device Boot Start End Cyl Blocks ID System
/dev/sda1 * 0+ (omitting) 1870 15020743+ 83 Linux
/dev/sda2 1870 7858 63127417+ 5 extended
/dev/sda3 0 0
/dev/sda4 0 0
/dev/sda5 9636 93- 746991 82 Linux Swap
/dev/sda6 1870 7673 61633309+ 83 Linux
/dev/sda7 9543 93- 746991 82

This problem only occurs when I shutdown -h if I restart, I'm ok.

Here is what is in grub too:

root (hd0,0)
kernel /boot/vmlinuz-2.6.24.19-server root=UUID=44056814-1515-4c7c-aa5c-f060c720e0c7 ro quiet splash
initrd /boot/intrd.img.2.6.24-19-server
savedefault
boot

I found a hit that said I need 384 ram for ubuntu - i only have 256. I will fix that, but before I shutdown, I was hoping someone could help me with this boot problem - since I'm not sure why/how I get it back up, - I'm afraid I may not be so lucky next time.

Thanks

bodhi.zazen
December 15th, 2008, 06:44 PM
See this page :

http://users.bigpond.net.au/hermanzone/p15.htm

Scroll down to error 18 :twisted:

nhasian
December 15th, 2008, 06:47 PM
C/H/S stands for Cylinders, Heads, Sectors. This information used to be printed on hard disks, but that was years ago i dont know if they still do that.

Is the boot partition at the beginning of the hard disk? (in the first 1023 cylinders of the harddrive)

brojard
December 15th, 2008, 07:00 PM
Problem resolved. Changed bios to AUTO and ensured that all the head,cylinder and sector entries were cleared before I proceeded. Last time when I set it to AUTO, I hit enter - which populated those fields from (defaults or previously stored info?) Anyway, leaving the fields cleared seemed to do the trick. Boots fine now.
Sorry if I wasted anyone's time.

Malalo
December 15th, 2008, 07:01 PM
I had the same error the first time I installed Ubuntu on my server. It's a very old machine (dual P2-700MHz) and apparently the BIOS didn't appreciate having a boot sector farther than the first 8 Gigs (I think) of the disk. So I had to manually set partitions with gParted during the installation, to make sure that the /boot partition was the first on the disk. Having done that, I never had any problems with error 18 since then.

oilchangeguy
December 15th, 2008, 07:12 PM
also see this thread:
http://ubuntuforums.org/showthread.php?t=1009967

oilchangeguy
December 15th, 2008, 07:14 PM
Problem resolved. Changed bios to AUTO and ensured that all the head,cylinder and sector entries were cleared before I proceeded. Last time when I set it to AUTO, I hit enter - which populated those fields from (defaults or previously stored info?) Anyway, leaving the fields cleared seemed to do the trick. Boots fine now.
Sorry if I wasted anyone's time.

please use the thread tools to mark your problem as solved.