Help identifying a PDP-11

Dave McGuire mcguire at
Sun Sep 16 14:39:18 CDT 2007

On Sep 15, 2007, at 4:01 PM, Tobias Russell wrote:
> Can anyone help me identify my latest PDP-11 rescue. Not been able  
> to get a good look at it yet as it is in a room packed (and I mean  
> packed) with junk. Machine consists of a DEC Datasystems cab (about  
> 35-40U with a blue bottom panel, pretty similar to light blue cabs  
> here:
> I'm not familiar with the DEC Datasystems versions of PDP-11s. Does  
> anyone have any background information on them?

   I have one of those.  It's simply a PDP-11/70 in a different type  
of cabinet with a different front panel...nothing else weird about it.

> Also, I'm pretty sure I've not lucked out and found an 11/70 as no  
> toggle switch console, any ideas on what other models were fitted  
> to these cabs. I'm guessing 11/34.

   I don't know offhand what other systems came in that type of  
cabinets, but what you have is definitely a real 11/70.  Your has the  
remote maintenance panel, which replaces the lights-and-switches  
front panel and allows DEC Field Service to dial into the machine's  
console and perform standard front-panel operations remotely.

   As I understand it, nearly all 11/70 systems were originally  
shipped with standard lights-and-switches front panels.  Later in  
their life cycle, though, DEC swapped out many of those "real" front  
panels for these remote access panels like the one you have.  Now for  
the important part: The lights-and-switches front panel was the  
property of the customer, and the policy was to leave them at the  
customer site.  If you got this machine from the original owner, it's  
likely that the real front panel is stuck in a box in the back of a  
rack, or in a closet somewhere.  Try to find can easily be  
put back into place.

   When Brian Hechinger and I scored three 11/70 systems from a  
publishing house in Pennsylvania years ago, they had these remote  
panels installed.  We found the real front panels and put them back  
the way they were supposed to be.  Incidentally, two of those three  
systems were of the DECdatasystem-570 ("corporate cabinet") variety  
like yours.

> Machines is fantastic condition having been stored for last 30  
> years. Comes with 2 x RK07s (in floor standing cabs) and a tape drive.

   Fantastic!  Umm, the drive to the left of the 11/70 in your  
picture looks more like an RM02/RM03 than an RK07 though...?  Can yo  

> Any advice on moving RK07 drives? Do I need to lock heads?

   They are top-heavy, so be careful there.  If memory serves,  
RK06/07 drives don't have a manual head locking mechanism.

   Congrats on that really nice system.  It is very similar to mine  


Dave McGuire
Port Charlotte, FL
Farewell Ophelia, 9/22/1991 - 7/25/2007

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