I guess XNU is the 'fixed' version of Mach. At least it powers all those iPhones and iPads.

And I do have the buildable source of Darwin 0.1/0.3 which is the equivalent of OS X Server 1.0

It's a.. Fusion of Mach 2.5 and 4.4BSD.  I've heard that NeXTSTEP is more 4.3BSD

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On Sun, Jun 23, 2019 at 9:40 PM +0800, "Jon Forrest" <nobozo@gmail.com> wrote:

On 6/22/2019 10:15 PM, Larry McVoy wrote:
> I've read the Mach source.  Not a fan.  If you look around you can find
> SunOS 4.x sources, not legal but it is out there.

> If you read the Mach code, nope, it's a tangled mess, there is no
> clear picture there.
> I read the papers and wanted to believe it was good, it is not.

There's one thing to keep in mind about some software produced in
an academic environment. Sometimes it's a collection of proofs of
concept of clever ideas that various grad student have hacked together
for their MS or PhD work. It's not intended to be production quality.

I don't know anything about Mach, but this was certainly the state
of Postgres when I worked in the Postgres group in 1991-1995. We
tried to use it as the basis for a big research project (e.g. Sequoia
2000) but spent (wasted?) lots of time fighting Postgres issues.
Eventually, long after I left the group, and after Mike Stonebraker
left Berkeley, a group of people who weren't associated with UC Berkeley
did a truly heroic job and "fixed" Postgres. The production quality
Postgres you see now is the result.

The BSD project was different, for all kinds of reasons.

I wonder if Mach was a Postgres or BSD style project.

Jon Forrest