[dredmorbius]

There were lots of other people banging out lots of other OSes. I've worked with many of them (S/360 and successors, VMS, S/400, CPM, among them).

What Unix had going for it wasn't getting started, but getting adopted. For a number of reasons, but among them two key advantages:

• It could be adapted to other architectures. That is, it was portable.

• It could be extended. Most particularly at UC Berkeley and MIT.

The simple-at-the-core bits certainly helped.

[hga]

But before that a lot of universities paid $800 (call it $3,000 in today's dollars) for a tape and site-wide license, and ran it on relatively cheap PDP-11s. And I've heard one or more of the team, perhaps before that, would travel with an RK05 disk cartridge seeding copies.

[dredmorbius]

Tapes shipped "from Ken, with love" are part of the legend.

Another significant factor was the 1950s consent decree under which AT&T operated, which prevented it from going into the computing business, as well as the lack of an explicit recognition of copyright for software. Effectively, AT&T couldn't sell Unix, even if it wanted to, so it had to give it away (or charge no more than the media fee for it).

This all changed after 1984 and the break-up of Ma Bell, giving rise to the UNIX Wars, Free BSD (1-800-ITS-UNIX!!), Minix, and a longing for the days when small furry creatures from Alpha Centauri were real small furry creatures from Alpha Centauri.