XPost: alt.folklore.computers   
   From: anton@mips.complang.tuwien.ac.at   
      
   Peter Flass  writes:   
   [IBM STRETCH bit-addressable]   
   >I don't get why bit-addressability was a thing? Intel iAPX 432 had it,   
   >too   
      
   One might come to think that it's the signature of overambitious   
   projects that eventually fail.   
      
   However, in the case of the IBM STRETCH, I think there's a good   
   excuse: If you go from word addressing to subunit addressing (not sure   
   why Stretch went there, however; does a supercomputer need that?), why   
   stop at characters (especially given that character size at the time   
   was still not settled)?  Why not continue down to bits?   
      
   The S/360 then found the compromise that conquered the world: Byte   
   addressing with 8-bit bytes.   
      
   Why iAPX432 went for bit addressing at a time when byte addressing and   
   the 8-bit byte was firmly established, over ten years after the S/360   
   and 5 years after the PDP-11 is a mystery, however.   
      
   - anton   
   --   
   'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'   
     Mitch Alsup,    
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)