On Mon, Mar 28, 2016 at 7:26 AM, Noel Chiappa <jnc at 
mercury.lcs.mit.edu  
wrote:
   From: Charles
Anthony 
  the missing piece of the rounding algorithim has
been identified:
     Only round if the mantissa was shifted more then 71 bits. 
 Wow. I'm really impressed that they implemented that in hardware, back
 then!
 Then again, they threw so many gates at the Multics CPU, I guess they
 figured
 a few more wouldn't matter... ;-)
 
 The floating point actually predates Multics (GE-635 I believe); I suspect
that the driving force for sophisticated floating point was the growing
'scientific computing' market, remember this was Cold War era and the
military was spending piles of money on nuclear weapon research. (I don't
have any documentation, just my informal understanding of mainframe
history.)
-- Charles
        Noel