The answer to all your questions: Maximum game sizes per machine
Remember: We Hate Micros (tm)

Micro		1-disk		2-disk			
-----		------		------	

TRS-80 MOD I	80K (81900)	87K PUR (89088)

OSBORNE		82K (83948)	90K PUR (92160)

ATARI		83K (84972)	90K PUR (92160)

TI-99		---		22K (22528) PRE (DISK1)
                                89.5K (91648) PUR (DISK2)

COMMODORE	> 120K

APPLE		123K (as of 1 Feb 84 -- per Dan Horn)

IBM		> 150K