I installed three O.S on one drive. I disconnected this drive and installed two more OS's on the the next drive. On the first drive all three were bootable and on the second only the first O.S. would boot. The second drive booted both O.S at first and then stopped. I used a rescue disk on the second drive with two on it and it made no difference. I did the same to the first drive and I sort of joined the to boot loaders together in a non appreciative way.

Is is practical to do what I tried doing and should I just multiboot off one drive? I would like about eight O.S's on the same computer.


Thanks in advance!

It is absolutely practical to do what you're trying to do, but I think you're overcomplicating your situation by swapping disks in and out... Let's assume you're using grub or grub2 as your boot loader...

OK, when you installed the OS'es the grubs would have been configured with just the drives/OS'es it knew about.

When you put the two drives live together, the available grubs' configurations would have been messed up.

I think that's why the OS stopped booting.

Ok, well a rescue disk is good, and joining the boot loaders is ok, it is just the manner in which you do it which is important: Assuming you're currently booting off the MBR of the first disk and pointing at the /boot/grub configuration on the second disk (e.g. that's my current config), you can use the rescue disk to harvest all the 'other' grubs' configurations (the menu.lst or grub.cfg files) and select/edit the lines describing the additional OSes into the one config file in the active boot partition. If you've been adding and removing disks during the installs, you may need to play with the
entries to align it with your current hardware configuration. For example, change it to Don't forget, you only need one MBR active and it needs to point to only one /boot/grub configuration file to get all your OSes accessible.

If you have any more problems, paste the output of and your grub config file.

It is possible - only the disk space is your limiting factor - but you'll probably need to get into extended partitions to do so, and share swap space amongst the linux OS'es. But have you ever considered creating VMs for the OSes you want to play with? A VM means you can have as many OS'es as you want running at the same time...

HTH

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Sharing swap is only reasonable, I do it all the time. You need about 10 GB in average for a distribution. With disks in excess of 2 TB available compute for yourself how many you can put on a disk . Here is a link to: GRUB How to install and boot 145 operating systems

http://www.justlinux.com/forum/showthread.php?t=147959

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I Googled "Boot Manager" today but I have made it this far so I will try to edit Grub which it looks like you are recommending.If all fails I will try something like "Gag". I could not find a decent guide to Grub but trying to configure it will probably have better results. I have been reading MS guides for info and even using WINE!

If possible it would be great to know What Grub stores and Where it stores it.

It would be helpful to members if you posted the operating systems you are using because some use Grub2, others use Grub Legacy and others still use Lilo.

Here's a link to Grub Legacy documentation:

http://www.gnu.org/software/grub/manual/legacy/

And to Grub2 tutorial:

http://www.dedoimedo.com/computers/grub-2.html

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I'm wondering if having two Mandriva's 10 and 08 is causing an issue? The last time I tried to load some O.S's I attempted to get 1 version of XP and Mandriva 08 on the first IDE drive and Mandriva 10 on the second which is a SATA. The boot loader found a good version of XP on the second drive from before so I was going to leave it. What happens in my closet with me and my computer is my business. That is going to be added to my sig. next.


The rescue disks I presenly have allow the use of a terminal and just reinstall the boot loader. I got this Grub file from Mandriva 10 and this is the fdisk for it as well.


The IDE drive is a 160 gig and the SATA is a 500 gig.

No.

I find a Puppy Linux CD can be a faithful friend in times of need.

I would say that translates as follows...
hd1=disk sdb
5=partition 5 (sdb5)
Which means you're counting from 1 and that entry maps to a valid partition in your sfdisk -l output
(stay with me here...)

Which means all these are valid entries pointing to /dev/sdb5
(which exists...)

BTW1. I'd say that the "map" entries are a byproduct of you swapping disks in and out.
BTW2. I would expect to see a "rootnoverify" entry for Win OSes.. but if it works for you...

So, if you're *still* counting from 1, this is /dev/sdb0
Which doesn't exist in your sfdisk -l output...
(still with me?...)

mmm...

(so, it's broken...what to do?)

Ok, lets work backwards...

If this entry were to be valid, it must point to /dev/sdb1
But then you're counting from zero
Which means the (hd1,5) entries above should really be

(ok, seems reasonable, so lets pursue this idea...)

Now, IF we revert to counting from zero THEN we're pointing to the /dev/sda1 NTFS entry. Good. We can see that one.


So the conclusion is:
Your config file is: Sometimes zero, sometimes one...

Can you see how grub could be getting all mixed up?


Therefore, start from scratch:
If you work from the premise that
AND

you count from 1

THEN

ALTERNATIVELY, IF

you count from 0

THEN

Well, that's my thought processes laid bare: Follow one or other of those numbering conventions, and I believe you'll be closer to a series of mappings that will work for you.

I hope it helps with your issue.

Regards!

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One of the better guides I have read is http://wiki.archlinux.org/index.php/GRUB and ran "grub> find /boot/grub/stage1" which returned "(hd0.5) and (hd1,4) if it matters.


This is from the device map from /grub/mapfolder (hd0) /dev/sdb (hd1) /dev/sda



Thanks for your expertise!

Well that's encouraging since that matches the linux partitions when you count from zero (see previous post):

I spent close to twenty hours on this and I can not find the info to go about this in an educated manner. I can understand the guides I read but they don't have enough info to do anything. If you have a problem with Grub you need to manually re-write your list file and no one on the Web knows how to do it but they can manage to write a guide for doing nothing. I'm sure their sites get a lot of hits though.

Here are some things I have learned from fooling with it.

Grub will only rewrite its MBR. Whatever the code does that runs it is mostly a mystery. The code tries to blindly fix the MBR. I tried it enough times that it would not boot at all. Grub will make a boot menu list of operating systems and not be able to boot them. You get the # 18 error.
If you put more than two OS on Grub it makes another boot menu so you first choose from one menu and go to another menu. This time around I installed XP Pro and Mandriva 08 on the first drive with Mandriva 10 on the second while leaving all the drives hooked up. When you go to the boot menu it lists O.S's it can't boot as well. When you reinstall a Linux Distro the install software will find old windows Versions and accurately put them on the menu but not the old Linux ones. If you put the MBR on a partition it will not load Grub. The set up menu (delete button) of BIOS just selects which drive to use the MBR from. Grub will use either drive natively if left on either (boot from setting).God knows why it is there anyway.

I don't think Grub is good enough to boot more than two O.S's. I had to repartition the drives with a windows installer to re-install a Linux with Grub. It would hang while booting the only Linux distro along with XP. Grub is using old info while installing fresh. Incidentally some times windows won't install on a Raw drive. It likes to go over another O.S so long as it is newer than it. It will just hang during the hardware stage.

So my advice to anyone is not to put more than two O.S's on Grub unless you know someone personally that can assist you with it. Saying the term "chainload" does not give you the ability to do it. I'm going to get some software that can help document what Grub does. I have the link stored on a thumb drive in Abiword but I don't have Abiword on this Distro yet so I will have to edit it in later. Trying something like Gag has got to be the more practical than fooling with Grub and not being able to obtain info to change the list file. If you can't build one from scratch you don't have the expertise to re-write it.

Thanks to everyone and especially Mr.Bit for your help! It allowed me to search for more info. Maybe I can find some stuff on Grub2 down the line.



Edit: this is the link for the software I mentioned.http://www.cgsecurity.org/wiki/TestDisk_Download


Here are the best links I could find for Grub that have actual information. I would like to thank the people that are responsible for keeping them on the Web!
http://www.gnu.org/software/grub/man...#Configuration

http://tldp.net/HOWTO/Remote-Serial-...WTO/index.html
http://mirror.href.com/thestarman/asm/mbr/GRUB.htm
http://www.centos.org/docs/5/html/In...ub-whatis.html
http://mirror.href.com/thestarman/asm/mbr/GRUB.htm
http://www.pcguide.com/byop/byop_Wor...Bootloader.htm

The Grub manual has a lot of info presented in a confusing way.
http://www.gnu.org/software/grub/manual/grub.html