Help answer threads with 0 replies.
Go Back > Forums > Non-*NIX Forums > General
User Name
General This forum is for non-technical general discussion which can include both Linux and non-Linux topics. Have fun!


  Search this Thread
Old 12-28-2006, 08:09 AM   #1
LQ Newbie
Registered: Jul 2006
Posts: 21

Rep: Reputation: 0
GRUB Error 21. Should I use BIOS to fix it?

Hi everyone

I have to admit that my problem might be a BIOS problem (something that I never used before), so maybe I should go and find another forum to ask, but I'm not 100% sure plus I don't know any other forums so please people help me.

I have 2 Maxtor hard discs 160 and 300GB. In the 1st I use XP and in the 2nd SUSE 10.0. Today I found that my mouse was no longer responding plus a huge program (a model) that had been running on linux for several months now was stopped. I tried rebooting the computer several times and in the meanitme closed most of the 10-15 windows that had been left open and unmounted another hard disc that I use only for the model. Maybe it was right after that that things turned really bad. The situation now is like this, when I reboot I get this error message:

GRUB Loading stage 1.5.

GRUB loading. Please wait...
Error 21

I tried some searching. Error 21 means "can not find disc". So I explored this BIOS thing for the first time. If I'm right the problem is in:

Standard CMOS Features

In there I found this:

IDE Primary Master [_NEC DVD_RW ND-45] <--this is my suspicion
IDE Primary Slave [ None]
IDE Secondary Master [ None]
IDE Secondary Slave [ None]
IDE Third Master [Maxtor 6V160E0]
IDE Fourth Master [ None]
IDE Fifth Master [ None]
IDE Sixth Master [ None]

So my guess is that the Primary Master (whatever that means) should be my other hard disc, something like [Maxtor 6V300E0] and not my DVD driver. But I couldn't find the way to change that. In the Primary Master menu it says:

IDE HDD Auto-Detection [Press Enter]
IDE Primary Master [Auto] (other options are None & Manual)
Access Mode [Auto] (other options are CHS, LBA & Large)

Capacity 0MB

Cylinder 0
Head 0
Precomp 0
Landing Zone 0
Sector 0

I tried several combinations of changes but nothing helped. Must I change the Primary Master? Then how can I do that?

Old 12-28-2006, 05:36 PM   #2
LQ Addict
Registered: Jul 2002
Location: East Centra Illinois, USA
Distribution: Debian stable
Posts: 5,896

Rep: Reputation: 352Reputation: 352Reputation: 352Reputation: 352
21 : Selected disk does not exist
This error is returned if the device part of a device- or full
file name refers to a disk or BIOS device that is not present or
not recognized by the BIOS in the system.
Your IDE listing a Primary master and a Third master, but no Second master is *curious*.

On the back end of the hard drive, there is a set of jumpers with a small (possibly white) piece that can be moved around on different pins (5 sets of two pins per set if I remember correctly). There should be a decal on the back of the hard drive explaining where to put that jumper to make a Master or Slave drive.

You settings of Primary and Third imply that you have two hard drives, each on it's own IDE cable. Is that correct?

If both drives are on the same cable, then they should show up in the BIOS and Primary master and Primary slave. If the two drives are connected to seperate controllers, you would get Primary and Third master.

So, I'd suggest starting with checking the jumpers on the drives.
1) are they on the same cable? If so, set the jumpers to master on one, and slave on the other.
2) Your /boot/grub/menu.lst (grub.conf on some distros) may not agree with actual disk locations. Are you disks called hda and hdb, or something else?

With both drives on the same cable, I'd expect hda and hdb. With each drive on a seperate controller, I'd expect something more like hda and hde (cd and dvd drives would be hdc and hdd).

The menu.lst must point to the correct drive and partition locations, or you will get error 21.

So, check the cables and jumper settings. If you still can't fix it, come back with menu entries from menu.lst, and possibly /etc/fstab.
Old 12-29-2006, 08:55 AM   #3
LQ Newbie
Registered: Jul 2006
Posts: 21

Original Poster
Rep: Reputation: 0
Thank you very much for responding bigrigdriver

I don't know what happened but my problem is solved. Today I switched my computer on and it was working, just like that. I still had problem with my mouse but I tried using another one and it worked. Maybe it has to do with the temperature that was very low in here yesterday.

In my BIOS - Standard CMOS Features a Fourth Master showed up so it's like this now:

IDE Primary Master [_NEC DVD_RW ND-45]
IDE Primary Slave [ None]
IDE Secondary Master [ None]
IDE Secondary Slave [ None]
IDE Third Master [Maxtor 6V160E0]
IDE Fourth Master [Maxtor 6V300E0]
IDE Fifth Master [ None]
IDE Sixth Master [ None]

Maybe it's strange that there is no Second Master but as it's working now I don't think it would be wise to mess with the inside of the box. I guess there is a logical explanation for that.

Again thanks for trying to help. You did help me understand some things.


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
what is Grub loading error 21, and how can I fix the problem! logiplex Linux - Software 26 06-30-2009 04:20 PM
Quick-Fix for Grub error 17 eagles-lair Member Success Stories 0 07-07-2006 02:17 AM
GRUB error 18.... not a BIOS problem Loopey SUSE / openSUSE 2 06-19-2006 07:01 PM
How do I fix the Grub Error 18!?!?! pastordan Linux - General 3 03-09-2006 08:20 PM
grub or windows error and how to fix netquest1 General 2 04-30-2004 03:27 AM > Forums > Non-*NIX Forums > General

All times are GMT -5. The time now is 06:49 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration