Re: Root device independent bootable disk images

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

> The question is, is there any reason to keep the existing machinery
> for specifying a fixed device name via the BOOTDISK make variable?

The only reason is there was no way to specify boot device independent
format in fstab(5) when I wrote the bootimage support.
(PR/45153 and PR/45155, back in 2012)

> Or in other words, can anyone think of an architecture or type of disk
> image where the "ROOT." reference might not work, or where a
> hard-coded root disk device in /etc/fstab might otherwise be
> desirable?

I have not tried "ROOT." syntax but it should work as MI monor, I think.

> The "build.sh live-image" target currently builds two live images each
> for i386 and amd64, with names containing "-wd0root" and "-sd0root",
> respectively.  With the proposed change, these would become almost
> identical, differing only in size and the OMIT_SWAPIMG setting, and
> probably ought to be merged into one.

OMIT_SWAPIMG was added to save time of dd'ing sd0root images
to memory sticks. wd0root images include swap partition for emulators.


Note one more TODO item is to use makefs(8) -O (offset) option like
src/distrib/utils/embedded/mkimage, to avoid concat MBR + ffs image files.

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Izumi Tsutsui