Hi, All, With the recent discussion of old PDP-11 core, I was reading over Warren Toomey's excellent description of piecing together the most ancient version of PDP-11 UNIX known, and dreaming of the day when I get my PDP-11/20 restored. I am missing, to my knowledge so far, two critical elements to getting the v1 UNIX kernel (and v2 userland) running on real hardware - an RF-11 and a KE-11A. I was figuring I'd have to make a hardware RF-11 emulator or tweak the code in such a way that some other device could be made to work in its place. The KE-11A seems to me to be a harder thing to replace with an alternative. I've read the manual on bitsavers and know the modules it's made of, but I was hoping to find a picture somewhere just to get a visual idea of its compexity. I know the general design of a number of 1970-ish DEC items, but mostly, I've treated Unibus devices as black-boxes - Unibus goes in, Unibus comes out, and in the middle stuff happens that does things. I guess I've been fortunate in that I've never had to do component-level repair of devices of that era (as opposed to lots of experience with older and newer gear). I've done lots of pre-OMNIBUS stuff, some OMNIBUS stuff, and lots of Unibus and Qbus single-card devices. The specific place I have little experience is with Unibus whole-backplane-era devices. The few that I've used worked when I plugged them in. So I'm not ever expecting to run across a loose KE-11A in the wild, so I have to consider what it would take to make one from scratch. Fortunately, it's a peripheral, not a processor option, so it's not festooned with attachments into the CPU itself (unlike, say, a PDP-8 EAE). I have lots of experience with making and debugging Unibus peripherals (COMBOARDs, among others), so I don't find that to be an insurmountable obstacle. I'm nowhere close to starting any sort of construction - I'm just hoping to find a photograph for now. Long before I'd start any sort of KE-11A project, I'd want to find a way to power up my three-BA11-11/20 (no authentic PSUs at the moment - those were harvested before I got the machine) and get it running. I'm expecting to be using XXDP and RT-11 to confirm that it works before I move on (fortunately, it's easy to drop peripherals like an RX11 on an 11/20 so I can import test programs from floppy or papertape as I debug any problems). Any pointers (in addition to bitsavers) on the KE11A would be much appreciated. I plan to tear into the changes made in simh to see how it works from a software standpoint, but the manual does have some good descriptions already. Thanks for any assistance, -ethan