[TUHS] 1972 UNIX V2 "Beta" Resurrected

[Adam Thornton]

https://en.wikipedia.org/wiki/DECtape

It's more like a very slow floppy drive than like a tape.  You may have
DECtape-I (tu56) or DECtape-II (tu58).  If it's DECTape-II,
https://retrocmp.com/tools/tu58fs is probably what you want; it doesn't do
great for VAX 11/730 booting, but it should be OK for file extraction.
SIMH has reasonable support for both -I and -II devices but you may have to
pull the code out and make your own tool--I don't know of a tu58fs
equivalent for tu56.

Adam

On Tue, May 27, 2025 at 10:18 AM Thalia Archibald via TUHS <tuhs at tuhs.org>
wrote:

> Yufeng Gao wrote:
> > The s1 tape is a UNIX INIT DECtape containing the kernel, while s2
> includes
> > most of the distribution files.
> [https://www.tuhs.org/pipermail/tuhs/2025-February/031420.html]
>
> Hello Yufeng,
>
> Do you have more details on the format of the s1 tape? I want to reproduce
> your
> work.
>
> The s2 tape is in the tap format, which was easy to decode, and I assumed
> that
> s1 was similar, just with its file headers on an earlier tape. I’ve been
> able to
> fairly accurately segment s1 into files by observing that blocks duplicate
> the
> tail of the previous block when they are not a full 512 bytes. I’ve
> written a
> tool for this and have segmented all the text files and some of the
> binaries,
> but I’m floundering on the rest. What you say seems to suggest that s1
> actually
> does have file metadata.
>
> Thalia
>
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