DEC "Junk" rescued - test-drb@ccmp.vtda.org

16 Nov 2005

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Subject: RE: DEC "Junk" rescued
   From: Paul Koning <pkoning at equallogic.com>
   Date: Wed, 16 Nov 2005 09:33:03 -0500
     To: cctalk at classiccmp.org

 >>>> "Allison" == Allison 
<ajp166 at bellatlantic.net> writes: 
 Allison> I thought the 11/24 was the 11/23 chipset (F-11) mated to
 Allison> Unibus rather than the Qbus.

Correct.

 > 11/24 is split I&D UNIBUS, right? 

Nope...

	paul 
Funny thing about PDP-11 system models.  Even number for the most part 
are unibus like 11/34 or 11/44 (11/05, 11/35 exception) and odd number
like 11/03, 11/23 are qbus.  

I&D for Chipset CPUs didn't start untill the J-11.  The F11 gave us
user/system register sets and the MMU.  The unibus J11 was the 11/84
I believe. 

F11 machines are a good workhorse 11s.  As far as my data goes all of 
the chip (F11 and J11) cpus on unibus are faster by some amount as 
there isn't the multiplxed address/data bus transaction.  Though I 
believe the real reason was to preserve the unibus IO investment
and generally higher IO transaction rate that unibus devices enjoyed.

Allison 