> some would say that you shouldn't slow down the 'default' FFS at all
> to do this.  i.e. clone the current ffs into a different mount-type,
> e.g. "bufs" (for backwards ufs...  8-), and do it there.

> While compatibility is nice, it's not clear that you want to slow down
> your 'default case' significantly to get it.

Uh, if testing a flag and branching requires a noticable amount of time,
especially given the lengths FFS goes to to avoid actual disk reads and
writes, you're using WAY TOO SLOW a computer...  Personally, I'd sooner
begrudge the extra 50KB or so a duplicate SFF filesystem type would take.

The default case would be to use your native byte order, and the overhead
of detecting that you don't need to do something out of the overhead ought
to be genuinely negligible compared to the effort already needed to (for
example) discover that you're on an FFS rather than an NFS or an MFS or...