From: joemonk64@gmail.com   
      
   > On a modern CPU, what happened to real mode programs   
   > was not that they had performance problems, but that   
   > they simply stopped working one day with 64 bit   
   > operating systems, plus they were permanently   
   > constrained to 1 MB. I don't know what the 64 bit   
   > issue was, and I don't really care at the moment.   
   > I'm just interested in why there ever needed to   
   > be a 1 MB limit - the answer is, there didn't.   
      
   The reason for the 1MB limit is a physical one. The largest chip at the time   
   was a 40-pin DIP. Subtracting 20 address pins only leaves 20 other pins for   
   CPU control signals.   
      
   So, segmentation was a hack designed to allow a larger address space while   
   using parts that were available at the time.   
      
   All of the popular CPUs at that time .... 8080A, 1802, 6502, 6800, Z80, F8   
   were all packaged in 40 pin DIP packages.   
      
   The first larger CPU I'm aware of was the Z8000/MC68000. They were in 64 pin   
   packages that didnt exist at the time of the 8086/8088.   
      
   Also, Windows is based on Windows NT, which itself is based on the DEC VAX/VMS   
   kernel (the principal architect was Dave Cutler, who Microsoft hired away from   
   DEC). So the command processor in WinNT is not the same DOS as Windows 95.   
      
   Joe   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)