A very long time ago The University of York (UK) secured the contract from the UK Science and Engineering Council (SERC) to write a unix Ada compiler.<p>It was a multi pass, 5-10 stage process (or more. I want to say 13 but time plays tricks) Very costly language to compile, in those days. (Vax 11/780 running Unix 32V, a precursor to BSD and Ultrix by some years)<p>The story was it emitted an error/warning code along the lines of "Congratulations you have used the most abstruse feature of the ADA language" -which the approval people made them take out before it got certified.<p>Wirth had a sabbatical residency in York around the time of the Ada language selection process, his choices didn't make it through the strawman/steelman process, I think they resurfaced in Modula-II. It was a pascal teaching department like many others in the UK of the time, so it made sense for him to spend time there. Modula-II is said to be a systems programming language too.<p>Ada was very hard to teach. The ideas of asynchronous, and exception handling didn't sit very well on young minds. Maybe now they're well enough understood to teach in Rust. At the time, the absence of a rationale around "why" was very strong. York had a miniature 2-lift engine model which it used as a proving ground for Ada programs and undergraduate projects. Lift sequencing is a bit of a black art in itself but if you put that optimality of "which lift, which direction, which floor" to one side, the mixture of real-time controls and sensors were probably a good fit. (lift == elevator for the other side of the Atlantic)<p>I remember some concern in the department the only logical endpoint for Ada was to code military flight control/weapons/radar systems, and people felt uncomfortable about the implicit participation in the UK War economy. This was during the time of the Greenham common protests against US nuclear forces on UK soil.<p>During the Alvey 5th Generation funding debacle ("Catch up with Japan at all costs") there was another round of this using GEC400 computers, again very directly related to Uk MOD needs for weapons control systems and what I think became the Nimrod airborne radar. Probably signals processing is a very good fit for Ada. (I didn't work on that project, or the compiler)<p>People said that the consistency of mapping data structures to devices, chip signal lines, real things, and the abstractions around that in types worked well in Ada. I found it horrendously complicated to understand. People might say C is a hack but the literal directness of C structs on a PDP11 or Vax to the underlying architecture worked pretty well to me. I guess the problem is that C was always too close to Assembler for some people. Bliss/32 was the systems programming language of choice in Digital, and I think continued to be used to write VMS, although I read now it was almost entirely written in DEC Macro assembler.