> As I know there are different types of UFS with big and small
> differents between them.

As I know, UFS is how the FFS is called under FreeBSD.

The UFS v2 (with 64 bit support so you can have TiB files)
is called FFSv2 on NetBSD. You can mount FFSv2 partitions
under FreeBSD. What isn't supported under NetBSD right now
is the background fsck (which uses snapshots to work under FreeBSD)
and the ACL.

> What types of UFS supported by NetBSD 3.0? Is any documentation
> describing format of this UFS?

FFSv1 is UFS on NetBSD.
FFSv2 is UFSv2 on NetBSD

(here UFS as in "UFS of FreeBSD")

> What about SunOS' ufs and HP-UX's ufs?

I don't know about those, and I'm not sure you can really
call those UFS :/

--
unzip ; strip ; touch ; grep ; finger ; mount ; fsck ; more ; yes ;
fsck ; umount ; sleep