1" paper tape buy ?

[Chuck Guzis]

On 26 Feb 2009 at 22:22, Dennis Boone wrote:

> I always assumed the 12-60 relationship existed because the 12-bit
> architecture derived from a previous CDC design, and because it was
> somewhere between helpful and important that they be a multiple.
> 
> But I haven't run into anything that talks about it.  Anyone have a
> reference I should have RTFMed by now?

Well, the PPU design is basically a reworked and regurgitated CDC 
160A, a 12-bit design, shared among 10 sets of memory and registers 
(A,P,Q and K) so each PPU got its slot in the barrel every 10 minor 
cycles (or every 1 usec., which was also the speed of a core bank).

But did the PP word size determine the CPU word size? I don't know.

Maybe a 72 bit word length might have made more sense, as that would 
have matched the 7090 double-precision word size.  On the other hand, 
everything about the 6000 architecture does "fit together" nicely.

Maybe there's something in the CHM oral history archives.

--Chuck