Thanks that's very interesting. So what happened to all of this 11-Clone hardware and who has the rights to RSX, RT11, and RSTS? Can a PDP-11 be done in FGPA or some other programmable logic solution? The only thing would be difficult to reproduce would be the edge connector sockets. Regards ? Rod Smallwood ? -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of Shoppa, Tim Sent: 11 May 2011 14:24 To: cctalk at classiccmp.org Subject: Re: pdp11 CPU on S100 board? The early Mentec boards had real DEC J-11's and onboard memory And serial ports (not too conceptually different than 11/53's or 11/93's). This spans the M70 through M100. Toward the end Of this era a big crimp was that J-11's were becoming unavailable (even via Clever routes like removal from old HSC's). Later Mentec boards (after J-11's dried up completely) went to high density TI bitslices and then custom ASICs. This is the M11 and M1. Mentec was all Q-bus. (AFAICT). As the Q-bus peripheral market dried up in The late 90's I remember some talk amongst the Mentec guys of making a M11 or M1 with onboard MSCP-compatible controller for ATA or SCSI drives but I don't think this ever got off the ground. Others made J11 CPU boards too for Q-bus, Unibus, ISA bus, etc. And there were others who sold DEC-compatible CPU's using bitslice and other higher integration techniques (e.g. QED/Quickware). The Mentec and others' main selling points, were cheaper prices and higher Levels of integration on the CPU board (thus reducing total system price). Tim.