From: arne@vajhoej.dk   
      
   On 7/3/2025 6:39 PM, Lawrence D'Oliveiro wrote:   
   > On Thu, 3 Jul 2025 10:56:26 -0400, Arne Vajhøj wrote:   
   >> 5) The idea of emulating one OS on another OS is questionable   
   >>      in itself. It is not that difficult to achieve 90-95%   
   >>      compatibility. But 100% compatibility is very hard. Because   
   >>      the core OS design tend to spill over into   
   >>      userland semantics. It is always tricky to emulate *nix   
   >>      on VMS and it would be be tricky to emulate VMS on *nix.   
   >   
   > It was always tricky to emulate *nix on proprietary OSes. But emulating   
   > proprietary OSes on Linux does actually work a lot better. Look at WINE,   
   > which has progressed to the point where it can be the basis of a   
   > successful shipping product (the Steam Deck) that lets users run Windows   
   > games without Windows. That works so well, it puts true Windows-based   
   > handheld competitors in the shade.   
   >   
   > That has never been done before. And it’s got to be a more difficult job   
   > than emulating VMS, with its much simpler APIs.   
      
   After 31 years of work, then Wine is pretty good. But I don't think   
   anyone would call it 100% compatible. Which is why many *nix users   
   still would run real Windows in a VM.   
      
   WSL 1 did the other direction. Worked decently, but not 100% compatible   
   either. So WSL 2 uses a VM to run the real thing.   
      
   >> Getting DCL, image activation, process permanent files,   
   >> subprocesses, logicals and symbols working 100% compatible on a   
   >> Linux kernel would not be easy. A lot hang on the 4 mode design and   
   >> DCL being in S.   
   >   
   > We don’t need to emulate the internals of DCL. We just need to be able to   
   > run users’ command procedures.   
      
   The issue is that the internals is reflected in the semantics. It   
   becomes messy.   
      
   Arne   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)