From: muta...@gmail.com   
      
   On Tuesday, September 13, 2022 at 12:24:43 AM UTC+8, anti...@math.uni.wroc.pl   
   wrote:   
      
   > Even if you insist on having exactly the same functionality,   
   > in PSP it is easy to do without wraparound: just put extra far   
   > jump at end of BIOS ROM and in PSP have jump to this extra jump.   
   > Cost is extra 4 bytes of ROM used by the jump and extra   
   > machine cycles to execute extra far jump per each call 5.   
   >   
   > Of course, once BIOS without this extra call was in the wild   
   > DOS had to support such BIOS-es and gate A20 was logical   
   > solution...   
      
   I was thinking - maybe MSDOS could have checked to see   
   if the BIOS had the required 5 bytes, and only if it didn't   
   would it start relying on the A20 being disabled (or   
   non-existent).   
      
   BFN. Paul.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)