The test could work both ways, if you really think about it: 1. I vaguely remember hearing stuff like that long ago - e.g. "Lotus 1-2-3 used such low-level fea

The test could work both ways, if you really think about it: 1. I vaguely remember hearing stuff like that long ago - e.g. "Lotus 1-2-3 used such low-level features of the OS (MS-DOS) and the hardware (PC) - for performance, that it would not work on PC clones that are close but not 100% compatible. 2. It could also have meant: MS-DOS clones and PC clones were different enough (even if just slightly, but in crucial ways) that Lotus would not work on clones.