Can you give some specific examples of software that crashes with 512K of RAM but works with 128K? (Both using the 64K ROMs of course.) It seems very unlikely to me, so I'd like to see it happen and maybe work out just why. From a Mac Toolbox perspective, you make a call that allocates memory and it either works or doesn't. I don't know why someone writing for a 128K mac would have a call checking the total available RAM - there was only the one size and its not like they had to make sure there was not only 64K or something... (especially given the lack of multitasking).

Ken