Perhaps we should start by looking at the difference between the Q-bus and S-100 bus. It also strikes me that that if we can do that that why not our own hobbyists Q-Bus CPU card? Made from USSR chips, FPLA or what have you. Let's try for say a 25 MHz PDP-11 CPU board. If Mentec and what happened was not such a deep dark secret, then that might have been a starting point. To try and explain my thinking lets look at classic cars as an analogy. Notice I said 'classic' not vintage or veteran. The UK has always been the home (with one or two exceptions) of small sports cars. One of the better known marques was (and is) MG. Their MGB and MGBGT models were produced in relatively large numbers and there are still something in excess of 100,000 still running. When production ceased a company bought up the tooling and still produces three or four MGB body shells per day strictly for the amateur restorer / reproducer market. The owners club stocks all the other parts and new 1975 model MGB's get built. So restoring a PDP-8 or PDP-11 is one thing but building a new one from scratch is more of a challenge. Regards ? Rod Smallwood (Digital Equipment Corporation 1975 - 1985) ? ? -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of Andrew Lynch Sent: 19 May 2011 00:14 To: cctalk at classiccmp.org Subject: RE: pdp11 CPU on S100 board pdp11 CPU on S100 board? jim s jws at jwsss.com <mailto:cctalk%40classiccmp.org?Subject=Re%3A%20pdp11%20CPU%20on%20S100%20bo ard%3F&In-Reply-To=%3C4DD317BE.4050704%40jwsss.com%3E> Tue May 17 19:50:06 CDT 2011 * Previous message: pdp11 CPU on S100 board? * Next message: pdp11 CPU on S100 board? * Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] ________________________________ I have raised the issue of documentation for the Soviet parts with a fellow who posted here recently who lives in Moscow. He will help with getting documenation translated if it can be had. I passed him three auctions with the parts I believe people here could bid on and obtain. He also looked for some information and sent it to me. [snip] -----REPLY----- Hi Jim! Thanks! I appreciate your enthusiasm for the S-100 PDP-11 CPU board project. I am willing to capture a schematic in KiCAD, layout a PCB, and get some prototype boards for build and test. At S100computers.com and N8VEM home brew computing project we have a substantial library of free/open source S-100 board designs we could reuse and borrow from to reduce technical risk. However we are missing an important part of this project -- someone to the design the board! I know almost nothing about PDP-11 and certainly not enough to design an S-100 CPU board based on one. Nearly any S-100 CPU board is a significant design effort even with the mere 8080 which the S-100 supports almost natively. Were someone to send me a handwritten schematic I could capture it in KiCAD and send it out for review. Hopefully the datasheets can be made available or translated. That would be helpful. Also, a reliable source of the chips would be helpful too. However, I would like for people to have realistic expectations. This project won't happen unless an actual designer steps forward. This is a substantial project and it will require many skilled and able hands. It would also need someone to write and/or modify an existing free/open source PDP-11 operating system to use existing S-100 peripherals. I suspect that is a major task as well for which we have no volunteers. I would like to see this project happen but it is missing key participants to make it work. Thanks and have a nice day! Andrew Lynch