The_Librarian

Had a little shufty at Hobbes, the OS/2 software archive, and was surprised to see that people still develop for an supposedly dead Operating System.

I then did a little nitpicking on virtualizers and OS/2, and discovered that OS/2 used the full instruction set of the Intel CPU's, which meant that it is very difficult to virtualize

According to Wikipedia :

OS/2 has historically been more difficult to run in a virtual machine than most other legacy x86 operating systems because of its extensive reliance on the full set of features of the x86 CPU.

And also :

VirtualBox from Sun Microsystems currently supports OS/2 Warp 3, 4 and 4.5 as well as eComStation as guests. Innotek (now part of Sun) also developed the “additions” code in both Virtual PC and Virtual Server which greatly improves host-guest OS interactions in OS/2. However, attempting to run OS/2 and eComStation can still be difficult, if not impossible to run, because of the strict requirements of VT-x/AMD-V hardware-enabled virtualization and only MCP2 is reported to work in a reliable manner.

QEMU and Bochs also support running OS/2 as they're full x86 system emulators and not virtualization software, and thus emulates the entire x86 architecture instead of relying on the host CPU, essentially allowing OS/2 unrestricted access to Ring 2, albeit an emulated one.

Interesting. So, if you're unsure whether you're running a real Intel CPU or not, just install OS/2, if it bombs out, then you'll know you're running a fake

Quite interesting. Makes one wonder what other OS'es makes full use of the entire Intel CPU instruction set.

But to do that, in today's times, would be foolish, as the OS will also need to run on AMD (and possibly, other) CPU's as well.

So glad I'm not coding any kernels...