Still seeking 3B2 information

Seth Morabito lists at
Fri Aug 14 14:28:27 CDT 2015

* On Tue, Aug 11, 2015 at 09:36:36AM -0500, Jerry Kemp <other at> wrote:
> Hello Seth,
> We were having a 3B2 discussion on the Sun Rescue list, and that got
> me to thinking about your emulator project.
> Can you share a status update?

Hi Jerry,

Sadly, it's been stalled for quite some time now. Current status is
pretty much the same as it was in January. The simulator can boot the
3B2/400 firmware, pass diagnostics, and read directories from virtual
floppy disks. Unfortunately, it can't get much beyond that -- trying
to boot the UNIX kernel still fails miserably.

I'd hoped to have much better progress to share, but Real Life
intervened by throwing me several major curve-balls in the first half
of this year, and it's only now that things are really starting to
settle down.

Even so, two things are still really holding me up:

1. Lack of good documentation for the system design of the 3B2

2. Lack of access to a physical 3B2

I hope to get #2 sorted out soon(-ish), so I can run a 3B2 with a
logic analyzer attached. There's still some mystery surrounding some
system timers and interrupts that I need to figure out before I can
really make progress.

I'd still love to get #1 sorted out, too. There are some 3B2 internals
docs on their way to Al Kossow that I hope will get scanned in the
next few months, I think that would help greatly.

Best Wishes,


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