There's a 2K hole in the Model I memory map above the ROM
On Tue, 12 Apr 2022, Yeechang Lee via cctech wrote:
Is this the hole that causes stock Model I to not run CP/M?

The problem with CP/M on TRS80 is that CP/M expects RAM from location 0 on up. Location 0 - FFh are used as a data structure for running programs, with location 100h and up as the "transient Program Area", where programs load and run.
TRS80 has ROM in bottom 16K.

There did exist MODIFIED CP/M ("FMG") that loaded above ROM, and ran programs that weren't too "hard-wired" to expect specific load location.

Parasitic Engineering (Howard Fullmer) and Omikron Mapper both made sandwich boards for the model 1 that moved things (under software control) to run "real" CP/M. They both ALSO sold 8" drive conversions for the Expansion Interface.

Grumpy Ol' Fred       

Reply via email to