Non-DEC 11's

Soviet PDPs

The PDP-11, as the PDP-8 before it, was cloned and copied extensively behind the so-called Iron Curtain. A number of plants produced PDP-11 compatible systems in the Soviet Union, including Elektronika-79 (11/70) and several machines without direct DEC analogues (DWK-4 with proprietary video controller).

I've never seen CIS realised on any Soviet-built clone. Elektronika-85 (Professional-350) was the most popular Soviet PC (of very low quality, though).

PDT-based IBM PC killer

Reported by Jerome Fine:

With respect to the different models of the PDP-11, your lists mention the PDT models which has a QBus backplane within a VT100. One model that I saw which was custom built included an 11/73 dual (KBJ11-A) along with a DLV11-J for ports. The memory used was a Cristlin 4 MByte quad board (some bright individual must have modified the backplane with a magnifying glass and added the wires to bring it up to 22 bits). The disk drive was an RD53, but it used a third party disk controller from SIGMA. Finally, they had also added a DHV11 to get an additional 8 serial ports. Except for the third party controller (an RQDX3 has no boot roms - also the memory could have used the MSV11-QC), all of the components were from DEC. They had stuck the disk drive under the video tube (evidently it was a real squeeze) with cables out the back to add a second drive. Does this example qualify for mention? It certainly was a power house and would have been the best scope on a PC if DEC had ever decided to put that much power inside the lowly VT100 as a standard.

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