[TUHS] Extracting files from various old dump/restore tapes

Warner Losh imp at bsdimp.com
Tue Aug 23 02:27:31 AEST 2022

FreeBSD deleted some compat code in the kernel some time ago, and it turns
out that restore used that to read old dump tapes, so we broke old dump
So you can't use FreeBSD's unmodified.

So 60011 is OFS_MAGIC and 60012 is NFS_MAGIC. Both of these are variants
on UFS, but really old. And given they are at different offsets, you'll
likely need
to reverse engineer the offsets used for the platform's dinode.

dump from 4.4BSD had 'natural' types (so long was used which would affect
offsets). It seems to be able to read both NFS_MAGIC and OFS_MAGIC tapes,
but you'll likely have to hack together u_spcl that's specific to the
platform which
may take a little trial and error if you don't know what the typedefs for
etc are. There's also a 4.1 dump/restore you might need (available in the
Alpha archive and likely all earlier versions in TUHS).

Without more specific data it's hard to know if there's an extant binary
can be run in emulation to read these tapes.


On Mon, Aug 22, 2022 at 9:35 AM Lars Brinkhoff <lars at nocrew.org> wrote:

> Hello,
> I have on my hands many images of tapes that seems to have been written
> by various implementaions of dump.  I see the magic numbers 60011 and
> 60012 in little and big endian at offsets 18 (16-bit version?) and 24
> (32-bit version?).  I don't know the dating of the tapes, but around
> 1980 would be a reasonable guess.
> Are there some easy to use (ready to run on a modern Unix) tools to
> extract files from such tape files?
> I'm not looking to restore a file system on disk, just extract the
> files.
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