Prev: UK Gov tells 600,000 staff to dump windopws and do Linux
Next: Which netbook ...
From: Whiskers on 16 Jul 2010 12:49
On 2010-07-16, Martin Gregorie <martin(a)address-in-sig.invalid> wrote:

[...]

> The one gotcha I see with a dual Linux boot set-up is what the updater
> does to grub.conf when it installs a new kernel. IIRC its bright enough
> to recognise a Windows menu line and ignore it, but I don't know if it
> can decide which is 'its' boot menu lines and only rearrange them. Nor do
> I know what happens when the kernel gets replaced in the distro that
> doesn't own the active Grub.

Things can get interesting when you delete the OS that was managing the
contents of the MBR, too!

> I'd also recommend that you follow the Grub manual to install a copy on a
> removable boot medium (preferably not a CD because you'll probably want
> to edit it) and set this one up so it prompts for boot parameters and
> executes what you type. Its manual should tell you how. This is not only
> a useful 'get out of gaol free' card, but will let you experiment with
> grub commands and get them right before you start changing boot menus.

GAG can be run from a removable drive, too. Probably easier to use than
Grub (let alone LiLo).

> ***Warning: AFAIK GRUB still uses BIOS disk services to access the disks
> its booting from, so if you're doing this on an old machine, make sure
> that:
> - none of the installed disks are bigger than the BIOS can handle
> - you've put both boot partitions where the BIOS can find them
>
> or one or more of the Linuxes will fail to boot. The Linux installer
> doesn't use the BIOS once its been booted so it isn't affected by these
> limitations - hence it can and will install Linux in places where the
> BIOS may be unable to boot it. I got scars from this many years ago when
> trying to make a dual Linux/Win95 system on a box with an AMI BIOS that
> couldn't handle disks bigger than 6.3 GB - and I was trying to leave
> Win95 on the original disk and put Fedora on a second 30 GB disk - I
> ended up getting a second 6.3GB used disk off eBay.

Such gotchas are why I prefer to use a stand-alone boot manager in the MBR
and put each OS's boot loader into the respective / or /boot partition
(you can put all your /boot partitions safely inside the size limitations
of the BIOS, if necessary). Microsoft OSs seem to insist on 'being first'
(or 'being the only'); a 'boot manager' can even overcome those
restrictions, I think - I haven't tested that though.

--
-- ^^^^^^^^^^
-- Whiskers
-- ~~~~~~~~~~
From: Alec Ross on 16 Jul 2010 17:55
>>>>
>>>Even easier:
>>>
>>>Edit /boot/grub/grub.conf. Comment out the hiddenmenu line and add
>>>
>>> timeout=5
>>>
>>>on the previous line. Now you'll see the boot menu for 5 secs - plenty
>>>of time to select a non-default kernel/os to boot.
>>>
>>>
>>>
>> Thanks, Martin. This is the sort of thing I was hoping for. Does this
>> depend on the order of os installation? i.e. I'm, concerned that if
>> Ubuntu were installed first, then the Fedora install would have left
>> it, and its boot/grub/grub.conf, into a partition not simply and
>> directly accessible for edit by a booted Fedora.
>>
>Does either installer offer you the option of using a pre-installed copy
>of GRUB? If so, I'd install that distro last, tell it not to install
>GRUB, and hope that it would configure the first installed Grub by adding
>its menu item to that - if it didn't then its easy to boot into distro A
>and edit a menu line in for the second distro.
>

Well, the honest truth is I don't know. That is, there may be
command-line options that I could use, or GUI options that I didn't
see/can't remember.

I do, however know that they differ in using grub and grub2. And in the
location and name of at least one of the configuration files.


>If neither offers you that option I'd expect that the last installed
>distro wins, so boot into it and edit its Grub menu to add a line for the
>first installed distro.
>

Noted.

....

[snip other useful advice]

Thanks again.
--
Alec Ross
From: Alec Ross on 16 Jul 2010 17:56
In message <slrni413c1.brm.catwheezel(a)ID-107770.user.individual.net>,
Whiskers <catwheezel(a)operamail.com> writes
>On 2010-07-16, Martin Gregorie <martin(a)address-in-sig.invalid> wrote:
>
>[...]

....

Thanks again, Whiskers.
--
Alec Ross
First  |  Prev  | 
Pages: 1 2 3
Prev: UK Gov tells 600,000 staff to dump windopws and do Linux
Next: Which netbook ...