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RE: Ah, when disk drives looked like washing machines

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In Reply to: RE: Ah, when disk drives looked like washing machines posted by jedrider on July 31, 2024 at 12:47:55

I worked for Calay Systems in the early 1980's, a manufacturer of CAD systems for automatic layout of printed circuit boards. I traveled the country installing and training customers on Calay "rip-up and reroute" systems. It basically went through several hundred iterations over night or longer to arrive at the best PCB trace layout for the components list it was given to work with.
Our system was based on the Q-BUS DEC LSI-11 that ran the RT-11 OS.
These systems would find the most efficient way to make connections between electronic components on a PCB. The resulting Gerber files were then sent off to a service that would convert the files into actual multi-layered printed circuit boards.
We interacted with the DEC via VT-101 terminal but the PCB designers used a mouse and a crude and hugely heavy color CRT. I don't recall what the color graphics subsystem was comprised of. I think it may have been proprietary.

Rip-Up and Reroute (Open in New Window)

Edits: 07/31/24 07/31/24

Follow Ups:

RE: Ah, when disk drives looked like washing machines - kh6idf 03:05:35 08/01/24 (3)
When I started my first job after college (EE degree), I was designing a set of circuit boards using CMOS logic chips and power MOSFET transistors.

We had a guy who did the circuit board layout after I had finalized the schematic. My prototypes were wire wrapped.

This was also in the early 1980's.

On one card, he routed a trace to ground along the perimeter of the board, traveling about 3/4 of the way around before reaching ground.

I got a call early one morning from the factory making the assembled boards. The boards were burning up during functional test. Turns out one of the power MOSFETS was oscillating at a frequency of about 400 MHz when it should have been just turning ON or OFF. We redid the trace to ground to take a much shorter path and that fixed it.
- RE: Ah, when disk drives looked like washing machines - AbeCollins 09:44:49 08/01/24 (2)
  Similar path here. Aside from the HAM radio hobby in the early 70's I got my start in electronics in the late 70's and 80's. I remember the original 7400 series TTL, 74LSxx, 4000 series CMOS, 74HCxx CMOS, and the ever so popular (to me anyway) 2N2222 and 2N2907 transistors we used for heavier duty load switching following the digital logic outputs.
  
  I did some wire wrapping too with a little tool that you placed over the IC socket pin and twisted between your fingers. The assembly lady 'pros' had battery powered wire wrap guns so we preferred having them do the more complex prototypes.
  
  Those auto-router systems were far from perfect. The designer had to go in and manually cleanup the layout before sending the Gerber files out to the PCB house.
  - RE: Ah, when disk drives looked like washing machines - kh6idf 11:14:33 08/01/24 (1)
    OK, one more story from my working days:
    
    After a few years as a circuit designer, I gravitated more toward the software realm. One day, we were testing a 777 flap/slat control unit for the first time in the lab, which had a real aisle stand, flap lever and one wing with flaps / slats / hydraulics, etc. Pretty much the real deal.
    
    I had done an analysis of the end-to-end logic for extending the flaps/slats from the flap lever all the way to the torque tube rotation. There were a dozen or so steps and many of them reversed the logic. So we weren't 100% sure of what the software would do when the flap handle was moved out of the zero detent. Would the tube rotate in an extend or retract direction? Only one way to find out..
    
    We had the mechanical guys who designed the gearbox watching, and as the handle was moved to extend, the tube was rotating in the wrong direction - to retract. The mechanical guys were in a panic, saying "oh no, we need to add another gear now and we don't have any room left!".
    
    I said, don't worry, we can change the one to a zero in the code and it will rotate the other way.
    
    The mechanical guy said "YOU CAN DO THAT??" :-)
    - RE: Ah, when disk drives looked like washing machines - AbeCollins 07:12:01 08/02/24 (0)
      I like that story. Reminds me of Tesla recalls involving millions of vehicles. The solution? An over the air software update.

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