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When Ada was first announced, I rushed to read about it -- sounded good. But so far, never had access to it. So, now, after a long time, Ada is starting to ca

When Ada was first announced, I rushed to read about it -- sounded good. But so far, never had access to it. So, now, after a long time, Ada is starting to catch on??? When Ada was first announced, back then, my favorite language was PL/I, mostly on CP67/CMS, i.e., IBM's first effort at interactive computing with a virtual machine on an IBM 360 instruction set. Wrote a little code to illustrate digital Fourier calculations, digital filtering, and power spectral estimation (statistics from the book by Blackman and Tukey). Showed the work to a Navy guy at the JHU/APL and, thus, got "sole source" on a bid for some such software. Later wrote some more PL/I to have 'compatible' replacements for three of the routines in the IBM SSP (scientific subroutine package) -- converted 2 from O(n^2) to O(n log(n)) and the third got better numerical accuracy from some Ford and Fulkerson work. Then wrote some code for the first fleet scheduling at FedEx -- the BOD had been worried that the scheduling would be too difficult, some equity funding was at stake, and my code satisfied the BOD, opened the funding, and saved FedEx. Later wrote some code that saved a big part of IBM's AI software YES/L1. Gee, liked PL/I! When I started on the FedEx code, was still at Georgetown (teaching computing in the business school and working in the computer center) and in my appartment. So, called the local IBM office and ordered the PL/I Reference, Program Guide, and Execution Logic manuals. Soon they arrived, for free, via a local IBM sales rep highly curious why someone would want those manuals -- sign of something big? Now? Microsoft's .NET. On Windows, why not??

pjmlp 2y ago
> So, now, after a long time, Ada is starting to catch on??? Money and hardware requirements. Finally there is a mature open source compiler, and our machines are light years beyond those beefy workstations required for Ada compilers in the 1980's.
phicoh 2y ago
I recently started re-reading "Programming in Ada" by J.G.P. Barnes about the original Ada. In my opinion, it was not that good of a language. Plenty of ways to trigger undefined behavior. Where C was clearly designed to be a practical language with feedback from implementing an operating system in C. Ada lacked that kind of practical experience. And it shows. I don't know anything about modern day Ada, but I can see why it didn't catch on in the Unix world.
- pyjarrett 2y ago
  > Plenty of ways to trigger undefined behavior I'm curious about this list, because it definitely doesn't seem that way these days. It'd be interesting to see how many of these are still possible now.
  - kqr 2y ago
    Search engines seem to no longer produce an estimate of the hit count, but here are some of the ways: https://duckduckgo.com/?t=h_&q=site%3Aada-auth.org+%22erroneous%22&ia=web https://duckduckgo.com/?t=h_&q=site%3Aada-auth.org+%22errone...
  - phicoh 2y ago
    I didn't make a list, but let me give an example. Page 22 where variable declarations are introduced: If a variable is declared and not given an initial value then great care must be taken not to use the undefined value of the variable until one has been properly given to it. If a program does use the undefined value in an uninitialised variable, its behaviour will be unpredictable; the program is said to be erronous.
- micronian2 2y ago
  I recall watching a presentation about C++20. During the presentation, the presenter said there were about 163 undefined behaviors in the C language (note: I think it was C99) which implied there were many more in C++ since it’s a much more complex language. Unfortunately, I don’t have a link to that presentation. You might have heard about the SPARK variant of Ada. I recall reading in an article many years ago that the original version of SPARK was based on Ada83 because it is a very safe language with a lot less undefined behaviors, which is key to trying to statically prove the correctness of a program.

pjmlp 2y ago

> So, now, after a long time, Ada is starting to catch on??? Money and hardware requirements. Finally there is a mature open source compiler, and our machines are light years beyond those beefy workstations required for Ada compilers in the 1980's.

phicoh 2y ago

I recently started re-reading "Programming in Ada" by J.G.P. Barnes about the original Ada. In my opinion, it was not that good of a language. Plenty of ways to trigger undefined behavior. Where C was clearly designed to be a practical language with feedback from implementing an operating system in C. Ada lacked that kind of practical experience. And it shows. I don't know anything about modern day Ada, but I can see why it didn't catch on in the Unix world.

pyjarrett 2y ago
> Plenty of ways to trigger undefined behavior I'm curious about this list, because it definitely doesn't seem that way these days. It'd be interesting to see how many of these are still possible now.
- kqr 2y ago
  Search engines seem to no longer produce an estimate of the hit count, but here are some of the ways: https://duckduckgo.com/?t=h_&q=site%3Aada-auth.org+%22erroneous%22&ia=web https://duckduckgo.com/?t=h_&q=site%3Aada-auth.org+%22errone...
- phicoh 2y ago
  I didn't make a list, but let me give an example. Page 22 where variable declarations are introduced: If a variable is declared and not given an initial value then great care must be taken not to use the undefined value of the variable until one has been properly given to it. If a program does use the undefined value in an uninitialised variable, its behaviour will be unpredictable; the program is said to be erronous.
micronian2 2y ago
I recall watching a presentation about C++20. During the presentation, the presenter said there were about 163 undefined behaviors in the C language (note: I think it was C99) which implied there were many more in C++ since it’s a much more complex language. Unfortunately, I don’t have a link to that presentation. You might have heard about the SPARK variant of Ada. I recall reading in an article many years ago that the original version of SPARK was based on Ada83 because it is a very safe language with a lot less undefined behaviors, which is key to trying to statically prove the correctness of a program.