On 12/21/2018 07:19 AM, Noel Chiappa via cctalk wrote:
Yes, PDP-5 and DEC LINC were made with "System Building Blocks", similar in technology to the board pictured, but single-width and wrapped in an aluminum frame, with a blue connector hand-wired to one end. Single-sided, paper-phenolic PCBs. Kind of similar to half of the board in the picture. I think this same technology was used in a number of other machines. Discrete transistors, diode-steered capacitor-coupled FFs, really ANCIENT technology.> From: Mattis Lind> I cannot figure out which early machine it comes from. They're called 'System Modules': http://gunkies.org/wiki/System_Module and they were used from the PDP-1 through (I think) the PDP-7; at least, this PDP-7 internals image: https://www.soemtron.org/images/jpgs/decimages/sn113robertjohnson85680004.jpg seems to show System Modules at the top, and FLIP CHIPs at the bottom. (I'm pretty sure even the first PDP-8 - the 'straight 8' - uses only early FLIP CHIPs - transistorized ones.) The DEC brochure for it (P5141) is a little puzzling; it says (p. 2) that "INTEGRATED CIRCUITS are basic elements of the low cost, newly designed silicon FLIP CHIP modules used throughout PDP-7", but AFAIK, the first FLIP CHIPs (R-series, B-series, etc) were all transistors; the later M-series were the first ones to have ICs. Maybe this is some old meaning of "integrated circuits"?
The "classic" PDP-8 was built with basically the same circuit technology, but on smaller, unframed glass-epoxy PCBs with etched and gold-plated card-edge fingers, with color-coded handles indicating what technology was on it. So, basic logic was R with red handles, memory boards (select, read amp, etc.) were G with green handles, etc.
Jon
