Can V1.2 file systems be mounted under 3.0

[George Robbins]

In article <1444 at esat.kuleuven.ac.be> ELSEN at esat.kuleuven.ac.be (Marc Elsen) writes:
> 
>     I will soon be upgrading from Ultrix 1.2 to 3.1 and I was wondering
> whether V1.2 file systems can still be mounted under Ultrix 3.1.
> The V3.0 Release Notes mention something about  a change to the
> Clean Byte value on p2-40.Further it is stated that fsck should be run
> at least once to make pre 3.0 file systems compatible with Ultrix 3.0.

As far as I know, there have been no major changes in the filesystem structure
that prevent mounting a 1.2 filesystem under 2.x or 3.x.  Somewhere along the
line, DEC fixed the "short directory" bug/feature from 4.2 BSD and then added
a "clean" flag to the super block.

The clean flag is basically advisory - if there have been no changes to the
filesystem since it was mounted/unmouted, fsck -p can skip checking it and
mount doesn't complain when you try to mount it.  You can still mount an
old (1.2) or "dirty" filesystem by using the "-o force" option to mount.

Warning: 4.3 Tahoe and Ultrix filesystems are less compatible - not sure if
this reflects any difference in the actual structure or just incompatible
notions on some superblock and partition table issues.

> Will this solve my problem or should I just create them again using 'newfs'
> and restore files from backup (tar or dump) ?

Still not a bad idea...

-- 
George Robbins - now working for,	uucp: {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr at uunet.uu.net
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)