Hi all -- I just added a PDP-11/44 to my collection and it appears to have some manner of cache upgrade; it's made by Digital Data Systems (DDS) and consists of two cards, one hex-height labeled "SC44 SETASI" (in the place of the normal 11/44 cache board) and a second quad-height labeled "1051" at the end of the first backplane. The two are connected via a ribbon cable.
I know DDS made some seriously nice upgrades for the 11/70 but I can't find anything on this board set at all. I'm assuming it's just a souped-up cache but it'd be nice to know more (and docs would be excellent of course). Thanks, Josh