cctalk Digest, Vol 64, Issue 3

Guy Sotomayor ggs at
Sun Jan 5 16:57:55 CST 2020

On Sun, 2020-01-05 at 23:41 +0100, Liam Proven via cctalk wrote:
> On Sun, 5 Jan 2020 at 23:30, Guy Sotomayor via cctalk
> <cctalk at> wrote:
> > 
> > Yes.  We first started with Mach 3.0 build MK58.  We did our final
> > fork at MK68.  We made some *significant* changes from what CMU
> > had (things like changing mach messages from IPC to RPC) and a
> > whole lot of work in the area of scheduling.
> Very interesting. If you are allowed to, you should blog about this
> somewhere -- it is historic stuff.

Yea, unfortunately I've lost most of the historical documentation
starting when we were all packed up to move from Boca Raton, FL to
Austin, TX and then when I left IBM in 1997.

I still have a set of the IBM Microkernel manuals (several 1000 pages
that was all written in Framemaker) and I *may* still have a CD with
the final set of sources on it (but where that might be would be an
interesting question).

> > Yes, a lot of things were based on Mach. One OS that you're
> > forgetting
> > is OS X. That is based upon Mach 2.5.
> Well, firstly, no, I wasn't. I didn't mention OS X, or macOS as it's
> called now, because it's based on NeXTstep. It's a later version of
> the same OS.
> Secondly, AIUI, NeXTstep used Mach 2.5 but one of the changes in Mac
> OS X 1.0 is that they moved to Mach 3 and updated the userland from
> BSD 4.4-Lite to FreeBSD then-current, hiring Jordan Hubbard to do
> much
> of that work..

No OS X uses Mach 2.5.  I worked in the kernel group at Apple for a
number of years and am fairly familiar with the kernel.  They may have
pulled a few things from Mach 3.0, but it is still fundamentally
Mach 2.5.

> > > MkLinux didn't get very far, either, did it?
> > > 
> > 
> > I think that was the original Linux port for PPC.
> It was, and I think only on Apple hardware. There were a few dev
> builds and then it disappeared, IIRC.
> [*Checkes*]
> Yup, OldWorld-ROM NuBus PowerMacs, and later OldWorld PCI PowerMacs
> --
> but later Linux supported PCI Macs directly.
> There were apparently 4 "developer releases", an R1 and an unfinished
> R2. Supplanted by Mac OS X, but apparently the Mach work really
> helped
> to get NeXTstep and "Rhapsody" bootstrapped on PowerMacs.
TTFN - Guy

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