On Mon, Mar 27, 2017 at 12:20 PM, Al Kossow via cctalk <cctalk@classiccmp.org> wrote: > On 3/27/17 7:37 AM, Systems Glitch via cctalk wrote: >>> I don't know of MOS memory appearing in 11/20s as built by DEC, but there's >>> no reason against it. > > There were 3rd party cards, Monolithic Systems, for example. > The problem with the 11/20 is that hex wide cards don't fit, the fans overlap > the unibus jumper area. > If you ever see hex-wide cards with a big notch in one end, they were > designed to work in the 11/15 11/20
Exactly. There are plenty of hex-height cards with MOS memory for Unibus (I have several for the 11/04 and/or 11/34 of a suitable size) but they would fit in an external BA11-K or BA11-L w/DD11-DK, not the CPU's BA11 because of the fans. That's why I was wondering if DEC ever made quad-height MOS modules for Unibus or if all DEC-supplied 11/20s and 11/15s had core and only core. -ethan
