I agree with much of what you say, Jan, particularly as it applies to machinery.

Back in the late '70's and early '80's, I installed digital 3-axis position displays on machines that would otherwise have had to be replaced with much more costly and, then, not so well-understood or trusted, in terms of their benefits ones. Not long after that, I installed remote control and monitoring capability on some of those machines, using their displays as the position indicator in order to provide feedback for the control systems. This meant that machines that worked perfectly well would otherwise have had to be replaced in order to provide digital control and monitoring capability. It might have been less costly, in hindsight, to have bought control and monitoring systems for those machines at the outset, but the monetary investment combined with the downtime for each machine was a sufficient justification for doing things the way I did them. It did cost about 40% of what it would have cost to install the entire commercial system at once.

Stepwise refinement is what has brought about the situation that I'm occasionally required to manage. It's not terribly difficult or disruptive. I made these enhancements with whatever MCU boards were available at the time, and often enough, some of them would have one MCU, while others used another, because microcontroller board ABC was cheaper that week than board XYZ that was used last month. That's why I'm stuck with supporting these old devices, that's why I want a monitor that's adaptable from one MCU to another, and that's why I'm looking for a full-function resident debug monitor that's available as 'C' source code. I'm just trying to make my work easier. What's more, I'm not a youngster any more, and these installations will probably outlive me. Someone else will eventually have to do what I presently do, namely nurse along these old-timers as their environment evolves.

One of my colleagues has been supporting similar work he did in the early '80's using 2nd-hand Commodore VIC-20 computers that were discarded as their owners upgraded, say, to the newer Commodore or Atari toys. He bought the old VIC's up at $5-$10 each and applied them to tasks such as this, and has been earning a fine living from them ever since. His customers are well-served and happy, as are mine.

RE