I agree

Markus

I like this site for one reason people in community and community itself is really like to help. (well nobody still helped to solve my arm kernel problem but this needed people with knowledge in this area).

2Erik_FL yep missed this. Disassembly of MBR w2k-XP code here (ENG).

But there is disadvantage of using standard windows MBR. You must change active partition before reboot(and stage2 must be at one same location).What if main OS FAILED? Yep, Live(CD|USB)(if you have one at hand)! Too long and sometimes impossible. On other hand in grub you have bootmenu and commandline with tools to make changes to disks,bootoptions etc.. couple of times this was lifesaver.

1 members found this post helpful.

Friend, it's time to bite the bullet and do this the right way - with emulation!!! At the very least, emulate the DOS system, there is absolutely no reason not to. DOSbox might not be the best solution, but VMWare, VirtualBox or Xen are a perfect fit.

A good engineer will tell you that the best solution is almost always the simplest one!

Emulation can emulate hardware features but it's very complex to emulate hardware timings and sometimes low-level features(limited by host OS).

mh, I think you're both right, in my opinion a virtual machine would be the solution in most cases. But referring to sunnydrake I would suggest to buy an old computer (an old 386 with 1MB of Ram would be sufficient) and install Dos there. For Win98 I would suggest a virtual machine.

Markus

That's a great site, sunnydrake. I've gone there many times to get detailed information for solving problems. Virtual machines work pretty well except for high-performance 3D graphics or specific hardware requirements.

The bare-bones Intel Atom motherboards with an included 1.6 Ghz. CPU are good for development work. You can get those for around $160 depending on the features. Add another $40 for RAM and a power supply and you can have something for experimenting. That does not include a computer case though. I just keep one computer case for rigging up hardware that I need.

I do software development for embedded applications. The hardware never looks exactly like what is in a virtual machine or PC. The operating systems are embedded, so they don't look like DOS, Linux or Windows. I do use GRUB to boot software. Just tack a multi-boot header in front of some assembly language code and load it in. Linux is a much larger and more complicated OS than what I work with, and I've only studied a small part of Linux source.

Please excuse - dont have time to read all of the above.

Disks are cheap ( I get 2 40 gig ata drives for $20 delivered on ebay) and all the motherboards I've used recenty allow you to pick the boot drive

Im currently using an MSI board. F11 gets a menu of which disk to boot - on prior board it was F8

I merely install an opsys on a drive, insatll as many drives as i want in the box, and boot the one i want

Multiple boots from the same disk made sense when disks were expensive, but you add a lot of complication and the risk that you will damage the system that really matters by messing up the boot sector. Make life easy - install multiple drives. My opinion.

Dick

Hello everyone. I got brief respite from the personal difficulties I was facing, and hope I can still get some help. I performed a test last night, which I hope might tell someone what is going wrong with my Ubuntu installations.

Erik FL and others suggested the reason the GRUB bootloader repeatedly failed to install, was because I was trying to install to a logical partition. I was reluctant to believe that for a couple reasons:

#1 - I had no luck whatsoever installing GRUB to the MBR either.

#2 - I HAD a working triple boot (DOS, XP, and Ubuntu 9.04) two years ago, on the SCSI RAID array. Ubuntu 9.04 installed just fine to an XT3 logical partition. Too bad my SCSI hardware failed a week later, and I couldn't afford replacements.

Still, I wanted to see if Erik was right. He suggested I re-partition the drive to give Linux a primary partition. However, I'm totally discouraged after 27 months of working on this system. I don't want to risk my working DOS / XP dual boot by starting from scratch, unless I've exhausted all other ideas. So I cooked up another idea. I booted the Ubuntu 10.10 live disk, inserted a 256MB USB thumb drive, and installed GRUB to the thumb drive, using Method #3 at:

https://help.ubuntu.com/community/Grub2.

For the first time ever a boot sector was actually installed! I used the "DD" command to create a bootsector.lnx file that I could chainload from NTLoader. And the file is no longer empty.

On reboot I actually got something other than a "-" cursor. I got the follwing response from the GRUB bootloader:

error: no such device: 2ab378ca-ec5b-491c-a1e2-29114fd43579
GrubRescue>


I don't understand the error message. Does this mean lead to a possible solution that won't require that I re-partition my disk and start from scratch?

JC

There are some other things I forgot to ask. Since I believe I've got a full Linux installation (Ubuntu 10.10) on SDA7, (XT4 logical partition), is there any way to MANUALLY create a bootsector that will load and run the Linux installation? I.E. with a hex editor? Is there any reason I couldn't have the bootsector on a floppy (or the USB drive?

Just to clarify, there are no XT3 or XT4 partitions. There are however, ext3 and ext4 filesystems.

No, that is not the problem. Linux can be booted from a logical partition with either Grub or a windows bootloader in the mbr.
Windows needs its boot files on a primary partition, no Linux system I am aware of does, certainly not Ubuntu.

Do you get the error you reported after selecting Ubuntu from your windows menu?
The error you are getting is that Grub is looking for a partition by UUID number. That's what the long number is. You would have to run the blkid command from a terminal to find out if you actually have a partition with that number. Since you believe you have an Ubuntu installation on sda7, the first thing you should do is compare the output of blkid for sda7 with the UUID you got in the error message.

I imagine there is but I don't know how.

No. It would be basically a boot partition and you would just need the Grub boot files there. You could set your usb to first boot priority, run update-grub on the usb and it should detect the windows install. Then when you boot from the usb, you would have all options. When you removed the usb, you would have your xp/dos options only.
You didn't indicate whether you got this error when you tried to boot from the usb directly or when you booted from your xp boot menu to the Grub on the usb. That is necessary information if you want help.

Here's a link to the Official Gnu Grub2 manual on how to make a Grub bootable CD. There is no reason you could not do this on a USB and 256MB should be more than enough.

Just to clarify, there are no XT3 or XT4 partitions. There are however, ext3 and ext4 filesystems.

No, that is not the problem. Linux can be booted from a logical partition with either Grub or a windows bootloader in the mbr.
Windows needs its boot files on a primary partition, no Linux system I am aware of does, certainly not Ubuntu.

Do you get the error you reported after selecting Ubuntu from your windows menu?
The error you are getting is that Grub is looking for a partition by UUID number. That's what the long number is. You would have to run the blkid command from a terminal to find out if you actually have a partition with that number. Since you believe you have an Ubuntu installation on sda7, the first thing you should do is compare the output of blkid for sda7 with the UUID you got in the error message.

I imagine there is but I don't know how.

No. You would just need the Grub boot files there. You could set your usb to first boot priority, run update-grub on the usb and it should detect the windows install. Then when you boot from the usb, you would have all options. When you removed the usb, you would have your xp/dos options only.
You didn't indicate whether you got this error when you tried to boot from the usb directly or when you booted from your xp boot menu to the Grub on the usb. That is necessary information if you want help.

Looks like grub is looking for a bootable entity (a partition on your HDD or possibly even on your USB thumb drive) with the above UUID. To find out which device has that UUID, boot from your bootable Ubuntu, plug in the 256MB thumb drive, open a terminal window, and enter the following:

Typo on my part...

Yes, that is how I'm attempting to start Ubuntu. I used the DD command to create a file called bootsect.lnx from the first 512 bytes of the USB drive where I installed the GRUB bootloader. I reference "bootsect.lnx" in Windows "boot.ini"

That's what I believed, but others here said otherwise. And I have tried repeatedly to install the GRUB bootloader to my ext4 formatted logical partition. However, when I use the DD command to copy the first 512 bytes of that partition to "bootsect.lnx" the result is always an empty file.

I believe the next response shows me how to do that. I will get that for you.


The FIRST thing I did after installing the GRUB bootloader to the USB drive (sdb1) see if I could boot directly from the USB drive. I made the USB drive the highest boot priority in the BIOS. On restart, the NTLOADER boot screen (boot.ini) presented.

So I booted the Ubuntu LiveCD, DD'd the first 512 bytes of sdb1 to "bootsect.lnx" on sda1, and tried to boot from that. Resulting in the error message I posted above. Would it be necessary that I also have all the GRUB FILES on the USB drive, if I wished to boot from it?

Thank you. I will get that for you as soon as possible. The target machine is at a different location. Please bear with me.

Anyone who tells you Linux has to be on a primary or have its boot files on a primary partition is wrong. End of story.

You need to install Grub to sdb not to the partition (sdb1). You can see that didn't work if you get the ntldr boot screen. That is because it found nothing on the usb and went to the hard drive with xp to boot.

Use your Ubuntu CD, go to a terminal and enter: sudo mkdir /mnt/sdb1 (hit the enter key)
then type: sudo mount -t ext4 /dev/sdb1 /mnt/sdb1 ( hit the enter key)
then type: sudo grub-install --root-directory=/mnt/sdb1 /dev/sdb

That should install Grub on the usb and you should be able to boot it. The reason you couldn't boot is that you just installed Grub on the partition of the usb and it was never accessed. You need it on the mbr on sdb.