New vm86 in 2.1.15, (dosemu needs upgrade)

Hans Lermen (
Mon, 16 Dec 1996 02:03:47 +0100 (MET)


Thanks to Linus, we now have (the long wanted ;-) enhanced support for
dosemu in the kernel, hence for kernels >= 2.1.15 the emumodule is no
longer needed. However, you have to keep the following in mind:

1. The first vm86plus patch that was distributed with dosemu-0.64.1 is
not compatible with the final one, because we did change the syscall
interface for vm86. The old one behaves exactly as before, the new one
is syscall 166 and currently only used by dosemu-0.64.2.
Dosemu binaries compiled for the old _vm86plus_ interface will
not work on kernel 2.1.15.

2. The vm86.h interfaces between 2.1.5 and 2.1.14 reflected the kernel's
internal pt_regs structure, hence did not contain FS/GS.
Now both user space interfaces (for 2.0.x and 2.1.x) are the same,
( the kernel translates to its own structure )
and you should be able to run a 2.0 compiled binary on 2.1 and vice
versa. However, binaries compiled on 2.1.5 ... 2.1.14 will bomb on

If you are interested in more details of the changes, have a look at
dosemu/doc/README.kernelpatches and get the new dosemu from

( it hopefully should be there tomorrow )