pdp 14/30 chassis on ebay

On 10/19/12 3:41 PM, mc68010 wrote: I'm sorry, but Mark had this completely wrong and didn't understand what an Industrial-14 was. The point was to replace mechanical relay logic. The PDP-8 was just an embedded controller that gave you a limited function keyboard and a display that showed you 'ladder logic' that could be downloaded into the core memory of the Industrial-14 through a high speed serial port. Once the system was running, the PDP-8 didn't need to be there at all. You didn't even need the PDP-8 for program development. The company I worked for in the early 80's wrote software that could run on a PDP-8 or 11 to do the same thing. It was not uncommon for a large industrial process to have a dozen Industrial-14s chugging away replacing a whole room full of mechanical relay logic. These devices weren't general purpose computers. At the time, there was still a concern about computers and 'direct digital control', where control system designers didn't feel that general purpose computers that were reliable enough and could provide the fail-safes necessary that they knew that they could design into systems with relay ladder logic. This is also why there is still a market for PLCs (Programmable Logic Controllers) into industry along with the fact that these systems are expected to run for decades. Also, PDP-14 and Industrial-14 are two different things. The original PDP-14 used wire rope memory, which was a kind of ROM that you had to program the ladder logic into by hand while the Industrial-14 used PDP-8e core.