Virtual 8086 mode

In the x86 CPU architecture Virtual 8086 mode, also called virtual-real mode, allows the execution of real mode code under the control of a protected mode operating system.

It is used to execute DOS programs in Microsoft Windows and OS/2 through Virtual DOS machines, in SCO UNIX through Merge and in Linux through dosemu.

Let's note that protected mode DOS programs, either 16 or 32-bit, do not execute in virtual 8086 mode, but rather in user mode (as long as they are DPMI compatible), so the above emulators do actually more than just supporting the virtual 8086 mode.