Burroughs core memory module <-> machine

(I just mentioned this in the thread about Burroughs part numbers, but am putting it forth in a separate question in case it gets missed by some readers.) I have a core memory module from some Burroughs machine. It is a large plug-in PCB about 16 inches square containing address & inhibit drivers & such. Mounted to this is a near-same-size daughter-board containing the sense amplifiers and the folded planar array of cores underneath a metal shield. It is organised as 32 KWords, 20 bits wide. Any suggestions as to what machine this may have come from? The 20 bits is the raw-memory-word width, one could speculate that some of those bits were used for ECC and the machine-word-width is smaller, although I'm not sure off the top of my head whether 4 bits is enough for ECC on 16 bits (isn't it >log2(n) for 1-bit ECC on n bits?)