IBM PCjr platform

Although it was quickly discontinued, the enhanced Tandy 1000 clone was created at the same time. The T1k was successful long after the PCjr was gone. Cartridge games can only be played on the PCjr, the T1k lacks the cartridge bus. PCjrs can be modded to full T1k compatibility or through a Gamemaster card. There are over 50 differences (41 to do with memory mapping), so this is no trivial matter. One such solution, for example, is a dummy memory cartridge for the cartage port that convinces the PCjr that there is no longer a cartridge port and the memory space reserved for it exists as main memory (in the high memory block).