[Info-vax] Poulson info from Dave Cantor

[glen herrmannsfeldt]

Bill Gunshannon <billg999 at cs.uofs.edu> wrote:
(snip, I wrote)

>> Note that IBM's z/OS running on z/Architecture machines currently
>> in production will run object and executables written over 40 years
>> ago for OS/360 on S/360 hardware.  There are incompatible changes
>> in privileged instructions, but problem state code runs just fine.  
 
> It is my understanding that the same is true of Unisys.

That could be.  I do know that Unisys is the favorite example
of ones-complement machines still in production.  Note that
both C and Fortran allow for ones complement, though not everyone
writes code that allows for it.  (They also allow for sign magnitude,
though C compilers for the 7090 are pretty rare.)

-- glen