Subject: Re: UFS status
To: Gilbert Fernandes <>
From: Pavel Cahyna <>
List: tech-kern
Date: 12/26/2005 16:41:25
On Sun, Dec 25, 2005 at 01:56:08PM +0100, Gilbert Fernandes wrote:
> > 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)

UFS also had support for TiB files:

$ dd if=/dev/zero of=big bs=1k seek=16g count=1 
1+0 records in
1+0 records out
1024 bytes transferred in 0.001 secs (1024000 bytes/sec)
$ ls -lh big
-rw-r--r--  1 pavel  users   16T Dec 26 16:30 big

It should also support partitions <2TiB. Support for bigger is said to be
buggy, but this is not different from UFS2.

> 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.

There are several versions (levels) of FFSv1 which are briefly described
in the fsck_ffs man page (under the -c option).

> FFSv2 is UFSv2 on NetBSD
> (here UFS as in "UFS of FreeBSD")

And some documentation about UFS can be found in fs(5) and dirent(5) man
pages and in header files under /usr/include/ufs/ffs and
/usr/include/ufs/ufs .

> > 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 :/

At least for SunOS you can.

Pavel Cahyna