PT Subsystem B and the VDM-1 / SOL

[atod]

This board set can be used with the VDM-1 and a parallel ASCII keyboard. It also has the option of using a RS232 terminal. If using the RS232 terminal does that limit some of the applications (on tarbell tape from my observation) that can be used with the VDM-1?

I have an IMSAI 8080 with this board set and am interested in it’s functionality.

Interestingly, the IMSAI is featured in the movie Wargames with what appears to be the Subsystem B setup, with two 8 inch floppies. I was not aware of such a configuration. Was it possible to use the VDM-1 as a TV terminal and run CP/M or IMSDOS from floppy media?

Thanks!

 

[deramp5113]

Subsystem B makes most any S-100 computer very similar to a Sol-20. There are some minor differences so some of the early games might need a patch or two to run properly - especially if they don’t use SOLOS/CUTER for keyboard input. The video scroll register address is also different between the Sol-20 and the VDM so that function may need patching in some games.

If you eliminate the VDM, then you’re relegated to mainly text based programs. CP/M for the Sol-20 will generally run fine on an RS-232 system using Subsystem B (assuming the same disk controller, of course).

CUTER reads the sense switches during initialization to determine where keyboard input comes from and where console output should go. These are separate settings, so you can have keyboard input come from an RS-232 port and still have console output go to the VDM. This is a good way to work around the parallel keyboard problem for now.

Mike