About

The editions nobody got to have

Unix spread in the 1970s partly because a 1956 consent decree kept AT&T out of the computer business. The system went to universities with its source for a nominal fee, and a generation learned to program by reading it. The 1984 divestiture removed that restriction, and what followed is the part everyone remembers: System V against BSD, lawsuits, a trademark parked at X/Open, and finally the SCO litigation grinding through the 2000s over copyrights the courts eventually found SCO had never owned.

Meanwhile the actual research carried on quietly at the same lab, on the same machines. Editions 8, 9 and 10 — 1985 to 1989 — were never released outside Bell Labs./proc, the stream I/O system, the file system switch and a network file system all appeared there first, and then the same people went and wrote Plan 9. The line did not stop because it was finished. It stopped because the company that owned it had become a different kind of company.

The code came back on 7 March 2017, when Alcatel-Lucent stated it would not assert copyright against non-commercial use of Editions 8, 9 and 10. ipnx is what that permission is for: not a museum piece behind glass, but Bell Labs Unix booted, usable, and carried forward into a world that never got to have it.

The name

ipnx began as iPad is not Unix — in the recursive-acronym tradition of GNU's Not Unix, and also a plain statement of fact, since UNIX is a registered trademark of The Open Group and an app that runs Research Unix may not call itself one.

It has a second reading, and that is the one that matters: Intellectual Property is not Unix. Unix the idea won completely. Unix the property was carved up among companies that, for the most part, no longer make operating systems.

Whose work this is

Almost none of it is mine. The system was built by a group that was never on an organisation chart — it coalesced voluntarily — and the manual's own convention was to attribute programs to individuals so that questions went to the right desk. That convention is worth keeping, so the repository names as many of them as I can properly credit, following Doug McIlroy'sA Research Unix Reader.

The parts you touch most directly in this app:

• Ken Thompson and Dennis Ritchie — the system, and the stream I/O that Eighth Edition is built on.
• Bart Locanthi — designed the bitmapped terminal, and programmed it frombitblt upward.
• Rob Pike — mux, the window system that downloads itself into that terminal, and the editors that culminate in sam.
• Peter Weinberger — the network file system that mounts your Mac's folders, written to bind a lab's machines into one logical system.
• Tom Killian — /proc, and so one of the ideas that made Plan 9 thinkable.
• Norman Wilson — waged a campaign against entropy across the software and the manual. Without him these materials would not exist to be run at all.

And for making any of it reachable today: The Unix Heritage Society,Dan Cross, Nokia for the 2017 statement,Seth Morabito for the 5620 emulator, and theopen-simh project.

Where it is going

Eighth Edition is the rehearsal. Tenth Edition has never been booted by anyone; it is being built inside the running Eighth, which is how a 1989 system would have been built in the first place. If it lands, it is a first.

And it will be a reconstruction, which is worth saying plainly rather than discovering later. There was never a pure Tenth Edition to restore: it was not built and shipped, it was hand-built on each machine by upgrading the Ninth in place. The surviving tape is one machine’s working tree caught mid-upgrade, and it says so in its own timestamps — the C library’s 261 pieces are dated across four years and twenty-seven separate days, most of them from a single 1989 build, the rest recompiled in ones and twos until 1993. The oldest pieces are the Ninth Edition’s, compiled by a compiler that is not on the tape and is now lost. Two different C compilers are needed to build what survives, because the changeover between them was never finished.

So ipnx’s Tenth Edition cannot correspond to a real Tenth Edition machine — no two of those corresponded to each other either. What it can be is faithful to this tree, built from Bell Labs’ own source by Bell Labs’ own compiler, with every departure written down.

After that: a ports tree for bringing software back to a machine from 1985, and an eleventh edition that never existed — the idea of finishing the sentence the Research line was in the middle of when it stopped.

Who made this app

Christine Tham, as a personal project, in her own time. It is free and always will be — that is a condition of the licence, not a marketing decision. Corrections, especially to the historical and attribution material, are genuinely welcome:chris.tham@hellotham.com.

See licensing for the terms every part of this runs under.