11/70 front panel - test-drb@ccmp.vtda.org

24 Oct 1998

...
  Date: Fri, 23 Oct 1998 09:15:43 -0400 (EDT)
 From: Ethan Dicks &lt;erd(a)infinet.com&gt;
 To: classiccmp(a)u.washington.edu
 Subject: PDP-11/70 rescued!
 Message-ID: &lt;199810231315.JAA24826(a)user2.infinet.com&gt;
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 The Computer Quonset Hut has its first aquisition - a pair of PDP-11/70's
 with peripherals. 
Lucky guy.

...
  My biggest disappointment is that the CPUs have the
corporate front panel,
 not the programmer's front panel.  Anyone have a spare front panel they
 want to trade? ;-) 
Actually the panel is better in some ways (except looks) than the 11/70
front panel.

I do prefer the DECdatasystem 570 (I think) 11/70 blue corporate
cabinet front panel for style. (The 11/74 used almost the same
front panel -- YES I did work with an 11/74 in DEC Princeton...
They did exist...

The "programmer's" front panel doesn't exist for the PDP11/70.
What you probably have is the 11/70 Remote Diagnostic Console
which allowed DEC to remotely diagnose the 11/70 (even when hung
in a microcode loop or power fail routine) from Colorado.

The front panel hooks to a microprocessor controlled card which interfaced
to a 300 or 1200/300 baud DEC or Racal Vadic modem (in auto answer 
mode) when the key is in remote.  Colorado would run a diagnostic chain,
examine the bus, read error logs etc.

...

 -ethan

 P.S. ISTR that PDP-11/70's and VAX-11/750's use the same hex-height 39-bit
 ECC memory boards.  Is this true?  I know that 750's had 256K and 1Mb 
 boards (and eventually 4Mb boards), but every jump up required a new
 memory controller (and backplane wires ;-)  What's the scoop on the 11/70? 
They do use the same ones... I don't think the 11/70 supported more than
the 256k MS-11K boards, though.

Bill
ex-DEC Field Service...