Re: Install from FreeBSD

[Roland McGrath <roland@gnu.org>]

> Is it possible to make the hurd filesystem from FreeBSD?  I'd like to
> try out the hurd, but I really don't want to install linux first. 

There are two answers to this, both of which are "yes, but you will be the
first to test it in recent memory".  

To start with, Mach should grok the FreeBSD partitioning ok, so that should
not be an issue however you want to do it.  I'm not keeping real close
track of GRUB, but last I knew it didn't know about the new-fangled freebsd
boot-loader configuration crapola, so you might want to just chainload the
freebsd boot loader rather than having GRUB boot your freebsd kernel.

I believe current freebsd systems support the ext2fs (Linux) filesystem
format.  You can either compile e2fsprogs (perhaps it's even in the ports
collection, I don't keep track), or maybe run a linux mke2fs binary under
freebsd's linux binary emulation, to make a filesystem.  If you are doing a
tarball install, then I presume you can figure it out from there
(i.e. mount the ext2fs filesystem, untar from freebsd, and then pick up the
linux-oriented instructions from there).  If you want to use cross-install,
then you might be able to do that using a dpkg binary under emulation, or
compile dpkg yourself for freebsd, but I'm not going to help you figure all
that out.

The other answer is that the Hurd supports the ufs/ffs (BSD) filesystem
too.  (It was the Hurd's first filesystem, in fact.)  The bad news here is
that the ufs filesystem has not gotten nearly as much maintenance and
testing as ext2fs in the last couple of years.  The format supported by the
Hurd's ufs filesystem is compatible with older BSD filesystems, and last I
knew it had no problem with FreeBSD filesystems, but I haven't kept track
of the BSD changes in some years and there may well be newer ffs format
features that the Hurd doesn't fully support.  The good news is that the
ufs filesystem has not gotten nearly as much maintenance in the last couple
of years, and it was fairly stable before I started breaking everything
else.  Note that running a BSD fsck on a Hurd ufs is a bad scene, unless
you really, really know what you are doing (i.e. use fsck without -p and
know when to say y, know when to say n, and know when to run).