[Mageia-discuss] Boot loader advice please

[blind Pete]

Antoine Pitrou wrote:

> On Tue, 28 Aug 2012 17:37:54 +0100
> Anne Wilson <annew at kde.org> wrote:
> 
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>> On 28/08/12 13:12, Renaud (Ron) Olgiati wrote:
>> > On Tuesday 28 Aug 2012 07:01 my mailbox was graced by a message
>> > from Anne Wilson who wrote:
>> >>>> I'm currently installing M2 as a dual boot onto sdd.  When
>> >>>> all data is transferred to the new disk, sda, sdb and sdc
>> >>>> will be removed. I assume that writing the boot loader
>> >>>> (language fails me, at the moment) to sdd is fine?  I know
>> >>>> it's a very basic question - brain is only half-functioning
>> >>>> just now due to external pressures. (sda has the old entry.)
>> >>> Just wanting confirmation that the existence of the old grub
>> >>> won't cause any problems :-)
>> > 
>> >> Unfortunately, it does cause problems - of course sda is checked
>> >> before sdd.  I assume that I will now need somehow get rid of the
>> >> grub on sda - what's the best way to do that? Faint bells are
>> >> ringing - about re-ordering disks, but in these days of using
>> >> disk IDs I'm not sure whether the old ways are still valid, and I
>> >> really don't want to screw things up to the point where recovery
>> >> is a very big job.  I'd appreciate thoughts from a mind that is
>> >> calmer and clearer than mine :-)
>> > 
>> > Can you change the boot order in BIOS ?
>> > 
>> That sounded a good idea.  It's so long since I did things like this
>> that I had forgotten it altogether.  However....
>> 
>> > I have installed M1 on an EeePC, with MSW on the bult-in HD and M1
>> > on a SD; just reassigned the HD order and the boot order, and all
>> > is well, boots from the SD and offers me the choices.
>> > 
>> > The only complication is when I change SD to install and try out
>> > another OS, I then have to remember to reset the HD and boot order
>> > in the BIOS or it directly boots Windows from the HD ;-3(.
>> > 
>> Mageia appeared to be starting up, but when it came to logging in, it
>> couldn't find the home directories (separate partition).
> 
> AFAIR, on some PCs, changing boot order will also change drive naming
> (the BIOS really changes the enumeration order of devices).
> So if you didn't use a "smart" scheme for your /etc/fstab entries, like
> UUID= or LABEL= mounting, mounting those partitions will fail.

Just to be horribly awkward, installers, boot loaders and operating 
systems can discover things in different orders.  This can be much 
worse if you connect and disconnect bits of hardware.  There might 
even be spinup delays depending on whether there is a hot boot or 
a cold boot.  (Some BIOSes allow for a time delay on some hard drives 
to lessen the startup current.)  

Worst case is you have to arrange the hardware then install, but 
if you know which boot sector the BIOS is going to look at you can 
problably sort out fstab and the boot loader after installation.  

-- 
blind Pete
Sig goes here...