dual boot and grub

I have also on /dev/sda Windows Xp Home and on /dev/sdb Ubuntu. I first installed Windows XP and then Ubuntu. Normaly grub should install on /dev/sda and replace the Windows Boot Manager. So in grub you could choice between Windows and Ubuntu.

Thank you Christain for your reply.
I would have to ask, did you have problems with mbr on the windows drive? I have read that the grub blows out windows mbr. If not Could you suggest how I could change this after the fact.?

Again thank you.

As fare as I know the Windows XP Boot Manager don't support multi OS.
With the default Ubuntu Installation the Windows mbr is overwritten with the one from grub.
I never had problems with that.

As the default Installation install grub you must have done something different. Can you explain that.

Christian
When I install Ubuntu on my slave drive I wiped out ntfs partition and created the fore mentioned dev files. When I got to the part where it asked where to install Grub I choose the dev/sdb2/ext4_ /
file. I guess you would say I did a manual install of Grub. So this Would not over write the mbr on sda or windows master drive.
I hope this helps not sure if it is stated correctly.

I thought that, wether where you install grub, always the mbr is overwritten with grub.
Did you deactivate /dev/sda as you installed Ubuntu?

No I did not. I had felt confident about changing partitions on slave with out effecting the ones on the master drive (sda) which has windows xp pro. As I mention I did not allow grub to be in stalled on master drive instead I choose to install on slave drive and placed in dev/sdb/ext4 / file dirrectory. So can the grub be move to sba?

Hello, I am 46 years old and after hearing my son boost about Ubuntu, I decided I would like to learn more about it and play with it to see how it works. So I downloaded ISO CD of 9.10 version (desktop) and proceeded to install Ubuntu on my second (slave) harddrive, master has windows xp pro . All went fairly well. I have a few question with regard to booting and hdd settings.
1st. In order to have boot choice of Ubuntu or Windows Xp pro I had to change my Bio's setting from hdd0/hdd1 to hdd1/hdd0.
        A) Can the Windows Mbr be changed to inclued Ubuntu? If so How?
        B) IF I physically change the hdd pin setting to make Ubuntu the Master and Windows the slave,will this effect the fact that Ubuntu is installed on sdb and effect Windows from being the master on sda?

2nd With current set up when starting computer up I notice that it takes a minute or two before Grub loads. Drive was set up as follows: /dev/sdb1/swap 2000m /dev/sdb2/ext4 / 79020m /dev/sdb3 /home 79020m.
               A) Would this be a result of placing the grub in the (/dev/sdb2/ext4 / ) directory. IF so how can I move it.
               B) Or should I start from scratch after making the switch of my hdd's? If so can a step by step direct pdf be emailed to me.?
Please advise. I am a do it you selfer and learn best from trial and error. Not always a good way but does come in handy when a friend or family member needs help.

Thank you and await your reply. God bless.
Rocco

A) Can the Windows Mbr be changed to inclued Ubuntu? If so How?

Usually we have Ubuntu on master disk /dev/sda and we can start Windows on /dev/sdb without any issue.
Also in this way you can run the Windows disk standalone by setting it as master.
So please don't play with Windows boot manager.

B) IF I physically change the hdd pin setting to make Ubuntu the Master and Windows the slave,will this effect the fact that Ubuntu is installed on sdb and effect Windows from being the master on sda?

Please put the Ubuntu disk as primary and the Windows disk as secondary then try to start Ubuntu.

if it start please simply try open a terminal from Application→Accessories→Terminal and type:

sudo update-grub

give your user password when requested, you don't see nothing when you type it, then press enter

Then reboot your pc.

Hth

Thank you Marco for your response.
 So if I proceed with changing pin settings and physically move the hard drives, This would not effect Ubuntu or windows? My own thought says it should not but I just want to make sure.

Rocco

Due to a lack of final answer I will close this session.

Hi ?

Is it too late to give answers here?

There seems to be a lot of confusion over some very simple things. Perhaps i could help clarify?

Regards from
Tom :)

Hi again :)

Ok, to clarify the thing about MBRs. Each hard-drive has 1 and only 1 MBR. This is a pointer to tell the bios where to find the bootable part of that hard-drive.

When you switch the machine on it performs a few tests of the hardware attached and then boots into the BIOS. The bios contains a list of devices that it checks in order to find a bootable device. Typically, by default, it first checks for "internal hard-drives" which can be a real pain. To start using linux you have probably already changed the "boot order" to something like this ...
1st = Cd/dvd-drives
2nd = usb/external drives
3rd = internal ide/sata drives
In that example the bios would check to see if there is a bootable cd in the primary master cd/dvd-drive, it might then check other cd/dvd drives. If it finds one it passes control over to the bootable cd and that ends the bios stage. If there is no bootable cd/dvd then it would next check to find any external drives and would check these in order, 1 at a time.

If it still hasn't found something that can boot then it looks at the MBR of the primary, master drive which gives it an address of somewhere bootable. MicroSquish would like to make sure it always boots into their boot-loader "ntldr". Linux/Grub would like it to boot into Grub or Lilo. Once the bios has found the address from the MBR it then gives complete control over to whichever boot-loader it finds at that address.

Grub = GRand Unified Boot-loader
Often this has been used to replace ntldr even on purely Windows machines in order to repair a "dead machine". It can be used to boot straight into a single OS on your system, even if that is Windows. However, it prefers to generate an automatic list of all the OSs available on your system. That could include an OS on an external-drive or a slave-drive. Since the menu is contained in a simple text-file you can change it to do all sorts of wonderful things but the automatically generated list is usually very straight-forwards.

Note that people often talk about "fixing the MBR" which is an unfortunate term to use because it implies the MBR got broken. However, in terms of "fixing the MBR" think of it like "fixing a horse race". People also say "repair the MBR" and again there is the implication that the MBR was damaged which is extremely unlikely.

Ok, so once the MBR of your boot hard-drive has been "fixed" to something you dont want you can re"fix" it back again quite easily. To "fix it" to point into Windows you will need to boot into the Windows on that drive and get to a command-line and type in "fixmbr". It really is that easy.

Ok, so you might be curious about what happens to the MBR on the slave drive. After all the bios was only interested in the one on the Master Drive but the slave drive also has an MBR. The answer is that the slave-drives MBR gets completely ignored unless the Master drive is massively damaged, even then it is more likely that the bios would generate an error message rather than do something useful. The bios is an extremely tiny OS and there is some talk of making it slightly less rudimentary sometime in the future.

My way of dealing with this problem would be to set it up so that the Windows drive was the slave-drive and then install Ubuntu onto the 'new' Master drive leaving the Windows drive untouched. The plan being that i could easily switch the 2 hard-drives around again leaving people unaware of the linux option. To setup such a system on your machine would now take a little repair work but starting by switching the Windows drive to being the slave drive would be a good first step from where you are now.

Hopefully this might have clarified the MBR issue. Please let us know and feel free to ask questions in this thread about that. Then i can perhaps help you unravel the confusions created by people so far in this thread about the other issues.
Good luck, apols and regards from
Tom :)

Hi again again :)

Ok, so there has been a lot of confusion and inaccuracy in this thread. Going back to the original question and trying to forget/ignore subsequent posts.

1st A) Can the Windows Mbr be changed to include Ubuntu?

Ok, the MBR does not belong to Windows, it belongs to the hard-drive. Yes, the relevant MBR can be "fixed" to point at Ubuntu, or more accurately "fixed" to point at Grub. Grub should then automatically default to give you a menu offering Windows or Ubuntu.

... If so How?

It's the default when you install Ubuntu (or other linux) onto your system, either with or without Windows being retained.

        B) IF I physically change the hdd pin setting to make Ubuntu the Master and Windows the slave,will this effect the fact that Ubuntu is installed on sdb and effect Windows from being the master on sda?

This is an excellent way to do this. Initially there may be a little confusion because the Ubuntu hard-drive's MBR could be pointing anywhere/nowhere. This is easily fixed through using the Ubuntu Cd as a LiveCd and following the same instructions that are in this guide
https://help.ubuntu.com/community/WindowsDualBoot#Recovering%20GRUB%20after%20reinstalling%20Windows
Note that you do not need to reinstall all of Ubuntu to do this. Once you are used to re-fixing the mbr it takes about 3 minutes after you have booted into a linux OS.

.

2nd With current set up when starting computer up I notice that it takes a minute or two before Grub loads. Drive was set up as follows:

/dev/sdb1 swap 2 Gb
/dev/sdb2 ext4 / 79 Gb
/dev/sdb3 ext3? /home 79 Gb

A) Would this be a result of placing the grub in the (/dev/sdb2/ext4 / ) directory. IF so how can I move it.

Nope, the boot-up time taken to reach the grub menu is about the same time as it used to take to produce the Windows splash screen and load-bar? This time delay is a function of the computer's hardware (specifically the cpu speed and ram speed&size) and bios. Note that the LiveCd of Ubuntu does include an option to "Test memory" and this might fix a few problems in the Ram which might make subsequent boot-ups faster. The memory test marks bad-blocks in the ram and ring-fences them to prevent them being used at all in the future. It does take ages to do this test tho, perhaps an over-night task to let the machine get on with on its own. You could risk updating the bios in some way, perhaps the simplest would be to restore the bios to factory defaults to start with. There is not really a lot you can do about this time except to upgrade hardware.

               B) Or should I start from scratch after making the switch of my hdd's? If so can a step by step direct pdf be emailed to me.?

Personally i would recommend avoiding messing around with that stage of the boot-up process. There's a lot of irreparable harm that could easily be caused for a potential gain of a few seconds at best. The risk is not worth the gain.

Good luck and regards from
Tom :)