Mainframe stuff... - test-drb@ccmp.vtda.org

19 Sep 2001

On September 19, jkunz(a)unixag-kl.fh-kl.de wrote:
...
     The 8700 and
the 8600 are very different machines.  The 8700 uses
 VAXBI, and is mounted in a chasiss similar in size to that of the
 8600.  I don't think there's any XMI in there.

   Incidentally, the 8700 can be turned into an 8800 by plugging a
 second CPU card set into the machine.  Hmmm. I got confused by:
 http://www.de.netbsd.org/Documentation/Hardware/Machines/DEC/vax/sections.h…

 There is the 8600 (aka 11/790) listed as a SBI machine.
 There is no reference to the 8700. 
 The 8800 is listed as:
 	Basically an 8550 processor in a bigger box with space for additional
 	processors to make it into an 8820 or 8840
 The 8550 is listed: 
 	XMI processor/memory backplane with VAXBI I/O

 According to http://anacin.nsc.vcu.edu/~jim/mvax/vax-perf.html the 8k
 VAXen, except the 8600, are pure VAXBI, no XMI. XMI came with the 6k
 VAXen. 
  The only 8K machines that I have personal experience with are the
8200, 8250, and 8350.  They're definitely all pure BI machines...the
CPU and memory are BI cards.  The 8700 has BI busses for I/O but the
CPU (made up of multiple large boards) is definitely *not* BI.

...
  So I assume the "base" machine is the 8550.
In a biger chasiss it is
 named 8700 
  I've never seen the innards of an 8550, but I can tell you that the
8700 processor is several very large non-XMI boards...maybe six boards
in all, about twice the size of XMI boards, that use ZIF connectors
similar to those used in XMI and BI.

  The VAX CPU Summary lists both the 8550 and 8700 as 6 VUP machines.

...
  and with a second CPU the 8700 is called 8800? 

  Yes, I can confirm this.

       -Dave

-- 
Dave McGuire
Laurel, MD