I386 has native way to switch to PM, no need triple fault trick and it
was introduced by Intel in 1985. For those who wanted to be compatible
with 286 there was a trick invented back then to switch to PM in a
portable way between i386 and i286:
http://www.rcollins.org/ftp/source/3fault/reset.asm
I doubt that OS/2 was not updated to use something like this.
I can't test 16-bit OS/2, so if someone would like to give it a try
that'd be great. It'd be interesting to see what method it uses.
I will try 16-bit Windows 3, and MS-DOS with HIMEM.SYS and Turbo C++ to
see if (a) they still work and (b) what method they use.
16-bit OS/2 is not working at all, it stops in booting the installation floppies because of unknown CMOS error.
That was last time I checked in about 0.7.0.
I know that between 0.9 and 0.10 still crashed on same "STDIO line", however I don't know if it is the same CMOS error, so I don't know what will happen when it triple faults because the kernel still did not tried to (apparently).