> But there’s a nuance in that OS/2 1.x used 286 protected mode the way Intel had intended it, by booting into it and never returning to real mode ( OS/2 had t

> But there’s a nuance in that OS/2 1.x used 286 protected mode the way Intel had intended it, by booting into it and never returning to real mode ( OS/2 had the ability to run DOS programs in a DOS box. my recollection was that OS/2 had to switch back to real mode to do this (thereby suspending all the OS/2 native processes.) Windows 3.0 in standard (286) mode did something similar. All this was done with triple faulting, iirc: http://www.rcollins.org/Productivity/TripleFault.html http://www.rcollins.org/Productivity/TripleFault.html > Steven Sinofsky writes about it in his personal Microsoft history: You might like Larry Osterman's recollection of this, if you haven't already seen it: https://www.landley.net/history/mirror/ms/davidweise.html https://www.landley.net/history/mirror/ms/davidweise.html