From: cr88192@gmail.com   
      
   On 10/4/2025 5:44 PM, John Levine wrote:   
   > It appears that Michael S   said:   
   >>> The last widely used single address space systems I can think of were   
   >>> OS/VS1 and OS/VS2 SVS,   
   >>   
   >> How would you call OS/400 (nowadays, IBM i) ?   
   >   
   > I haven't looked at it for a while but I think you're right.   
   > They have POSIX compatible APIs, wonder how that works.   
   >   
      
   FWIW, I suspect that the number of programs that use "fork()" without   
   immediately calling "exec*()" is probably fairly small.   
      
   AFAIK, programs that depend on full "fork()" semantics wont generally   
   work on Cygwin either, as IIRC it is just sort of faked by copying the   
   local stack frame and spawning out a new thread that terminates on the   
   "exec*()" call.   
      
   Apart from non-PIE ELF or similar, not much else doesn't work in an SAS.   
   Though, ABI tweaks are needed to make things efficient (eg, not needing   
   to load in a new copy of the binaries for every new process).   
      
      
   >>> I suppose there could still be single address space realtime or   
   >>> embedded systems where all the programs to be run are known when the   
   >>> system is built.   
   >>   
   >> IIRC, Windows CE supported SAS mode of operation just fine without such   
   >> limitations.   
   >   
   > For that matter, so did MS-DOS and Windows up through 3.0.   
   >   
      
   Not sure if 16-bit protected mode segmentation counts as SAS though.   
   MS-DOS, maybe, as one could do address math on the segments.   
      
      
   FWIW, some of my own engineering efforts here took inspiration from   
   Windows CE.   
      
   Like, the way I am using the "Global Pointer" directory entry in the   
   PE/COFF headers wasn't entirely a novel innovation on my end, ...   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)