One thing I've not done in a long time is bring up mpm. I did it one
and basically never used it after that. For those that want to try it
maybe there are a few war stories on whats the best path.
Also for those hat have a suggestion or opinion hardware as
in how much ram, how to page it for best performance, other
Since I'm working with multitasking again maybe MPM is the other
way to go?
I think the Propeller emulation is now stable enough running MP/M to
make a few comments. The board has 8 chips doing the hard work, mainly
a 40 pin propeller chip and external ram and support chips. This is
the same hardware that runs CPM 2.2 and on the CPM2.2 emulation the
serial ports and the local keyboard were merged together, as was
output to the vga monitor and the serial ports. For MP/M there are
three seperate emulations running:
USER 0 is the local VGA display and keyboard
USER 1 is the first serial port
USER 2 is the second serial port
and there is a 20x4 LCD display that any user can talk to.
In addition, any user can send characters to any other user through
the use of several virtual ports. And ^P copies characters to the
print spooler which any user can read. So it is possible to any user
to take over any other user and talk to it, run programs etc.
What is working in the last 24 hours is file transfers with xmodem. MP/
M can be running a program, eg MBASIC in user 2. But at the same time,
user 0 could type "USER 2" and do a DIR on user 2. Also, files can be
transferred between users using PIP. So to download a program, a
program on the PC end can send "USER 0" to the board, then run xmodem,
then send "USER 1" to return back to the proper user for the serial
port, and then send "PIP MYPROG.COM[G1]=MYPROG.COM[G0] to send the
file to user 1.
It sounds complicated, but it is easy to automate, and because every
user can talk to every other user, the whole thing can exist on one
board. Of course, you could have three physical screens and keyboards
running if you wanted - one VGA/IBM keyboard, and two Serial
The wireless code runs on user 2 and it is now written and just needs
testing. This code sends and receives data in packets, and sends the
decoded data to user 0.
I must say that MP/M is a lot of fun. I wish I'd had a MP/M computer
when I was a kid!