It's odd wording for sure, and doesn't feel like a common use of the term from before the arrival of monolithic integrated circuits. But there is some precedent; through the 1970s if not somewhat later there were "hybrid integrated circuits", often found in high performance A/D and D/A converters. Those are essentially compact circuit modules, but typically with unusual substrates like ceramic ones instead of PC boards, and surface mount components when PCBs used all through-hole components. So "integrated circuit" wasn't limited to the "monolithic" kind back then. I sometimes refer to "hollow state integrated circuits" to describe the complete multi-stage amplifier in a single package built by Loewe of Germany in the 1930s; look for "Loewe 3NF". paul

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. 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