&gt;system 5.0 never existed (typical Microsoft ignorance)<p>Microsoft Works was not written by Microsoft, typical random blog ignorance :P<p>Microsoft Works was developed and licensed from Productivity Software, company launched by ex Apple employees Don Williams &amp; Gene Carter. Microsoft threatened to destroy their company if they didnt sell. From horses mouth <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=Ai24F4Nel7U&amp;feature=youtu.be&amp;t=1h27m50s" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=Ai24F4Nel7U&amp;feature=youtu.be...</a><p>Mac OS revolutionary? Not really, try AmigaOS with preemptive multitasking on ~same level of hardware. Mac OS was a quick hack and a kludge, whole switcher&#x2F;multifinder ordeal was just sad for a modern 32bit operating system :(