The marking on the connector certainly says CDC. And the next to last picture shows a black faceplate that pretty much matches what you see in 6000 computers. Look in the Thornton book (http://www.bitsavers.org/pdf/cdc/cyber/books/DesignOfAComputer_CDC6600.pdf <http://www.bitsavers.org/pdf/cdc/cyber/books/DesignOfAComputer_CDC6600.pdf>) which shows a photo on page 31. Two connectors, 30 pins each in 2 rows of 15 matches what those memories use. You could confirm it further by looking at the number of core planes in the stack. The 6000 memory modules use 12 planes for the 12 bit PPU words (5 memory units combine to make the 60 bit CPU word). Finally, if you're inclined to take off some covers so you can look at the memory plane, the fact that it has 5 wires per core (x, y, x inhibit, y inhibit, and sense) is distinctive. Most other memories have only a single inhibit wire per core, not two. The details of how this is used are in chapter 4 of 60147400A_6600_Training_Manual_Jun65.pdf which you can find on Bitsavers. paul