Re: uefi boot?

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Tue, 17 May 2016 21:49:18 +0100
    From:        Patrick Welche <prlw1%cam.ac.uk@localhost>
    Message-ID:  <20160517204918.GA900@quantz>

  | Sure enough, that worked. So the sblock FFSv2 is just there to confuse me?

There are two different FFSv indicators in your dumpfs output ...

  | > > format  FFSv1
  | > > cylgrp  dynamic inodes  4.4BSD  sblock  FFSv2   fslevel 4

The first tells the overall format of the filesystem (directories, inodes, ...)
and can only be altered by a whole new newfs (it is a noticeable change).

The second is the format of the super block - v2 sblock format has a few
new fields in it.   As I understand it, v1 superblocks are automatically
converted to v2 wherever seen these days (by /etc/rc during the boot
process) (it is, I believe, backwards compat with v1 if you manage, somehow,
to find a kernel that does not understand the v2 sblock format - probably
quite difficult, it has been a long time now.)

What this means is that these days almost every filesys is going to say
"sblock  FFSv2" the only ones that wouldn't probably exist on a drive
that's been stored in a cupboard for the past 10 years or more.

The bootxx needs to read directories and look up inodes, it doesn't really
care about a little extra data in the superblock - so the format that makes
a difference to it (to which bootxx_ffsvN you need to install) is the
overall filesystem format, not the superblock format.

kre