What were the other major flaws?

einr · on July 15, 2023

* No standard ISA slots, instead a bulky and expensive ”sidecar” system

* Partially incompatible with regular IBM PC software

* Max 128K RAM

IBM likely did this stuff on purpose to avoid cannibalizing PC sales, but it ended up killing the Jr. Later on Tandy would borrow the PCjr sound and graphics hardware (superior to a normal CGA PC/XT) for a line of more successful personal computers.

bdowling · on July 15, 2023

> * Max 128K RAM

IBM sold a 128K memory expansion sidecar to bring it to 256K. There is also apparently a way to swap in denser RAM chips to make it 512K (640K total).

anyfoo · on July 15, 2023

And very expensive for all of that.

fuzztester · on July 18, 2023

Thanks