install guide notes: bootloader

[Adam Williamson]

Hey, folks (Jack especially). I have it on my (very long) todo list to
look through the changes to the installation guide and see if I can
contribute anything, but we were talking about this in #anaconda this
morning and I thought I'd outline it for the install guide before I
forget the plan again. Handling of bootloader install is somewhat
different in newUI. This is all about BIOS - UEFI is completely
different.

So what newUI is capable of is either installing the bootloader to a
partition MBR, or not installing the bootloader at all. Currently there
is no option to install bootloader to a partition, which was possible in
oldUI. Installing the bootloader to a partition is done only by those
who multiboot various OSes using a 'chainload' system - they have a
bootloader in the MBR which 'chainloads' bootloaders for each of their
OSes, each of which resides in the / or /boot partition for that OS.

The plan is for those who have such setups to just not install a
bootloader at all, and then do their bootloader configuration manually
post-install. Anyone who for some reason doesn't want a bootloader
installed to an MBR gets to do their own configuration.

In the UI you are able to specify which disk the bootloader should be
installed to (or that it shouldn't be installed at all). You do this on
the 'disk selection' screen - the first screen you see after clicking on
the 'Installation Destination' spoke. You have to click on 'Full disk
summary and options...' and you get a dialog that lets you pick the
target disk for the bootloader. To set it to not install a bootloader at
all, right now, this is the procedure:

"highlight whatever disk has the bootloader check, click the button, and
it'll unset that device for receiving the bootloader.  Thus, you should
not get a bootloader installed."

clumens notes that this isn't the best UI, but changing it would break
string freeze. See https://bugzilla.redhat.com/show_bug.cgi?id=867469
for details.

If you do not select a target disk, anaconda will default to installing
the bootloader to the MBR of the first disk (of those selected as
'install target disks' on the picker screen) that appears to be a viable
target, in enumeration order (so it'll try sda, then sdb, then sdc, and
so on, and the first one which passes the 'bootloader target' tests gets
the bootloader). This part is unchanged from F17.

Hope that's useful! Thanks.
-- 
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Twitter: AdamW_Fedora | identi.ca: adamwfedora
http://www.happyassassin.net