Jerry Pournelle on Fly-by-Wire and Programming Languages

Speaking about the Toyota software problems, Jerry Pournelle diagnoses the root of many quality problems in software:

When the computer revolution was beginning, there was a concerted effort to develop theories of computer languages. Two major champions of language reform were Niklaus Wirth** of ETH (Zurich, the Swiss Federal Institute of Technology) and the late Edsger Dijkstra (eventually held a chair at the University of Texas in Austin). Dijkstra spent much of his life developing theories on how to “prove” programs. They and some others were largely responsible for the movement that induced the Department of Defense to develop Ada, a strongly typed and highly structured language with some similarities to Wirth’s Modula languages. (The last time I discussed it with him Wirth did not care for Ada, in part because it became too complex with too many “features” and in part because he did not approve of exception handling — and that is one argument I’m not going to get into.)

More on all this another time, but my point is that in those times there seemed to be a lot more concern with languages, and with building languages that required good programming practices. In the various Wirth languages starting with Pascal the goal was to have the compiler catch incipient bugs: it took longer to develop a program that would compile, but once it did, it was likely to do what you expected it to do. Unfortunately the computer hardware of the time wasn’t up to huge programs in strongly typed and highly structured languages; it took a long time to compile a new addition to a program. The programming world turned to C and its derivatives, and in the early days a C compiler would compile almost anything, including very tricky uses of pointers and type changes.

I don’t know what language Toyota has used to develop its drive by wire programs, but I would bet reasonable sums that it wasn’t Ada or one of the Wirth languages.

To make it easier for people to become developers, they made it easier to write software. To deleterious effect.

By the way, be sure to use the word deleterious in a sentence this week. Vocabulary is a weapon.

One Response to “Jerry Pournelle on Fly-by-Wire and Programming Languages”

  1. dustbury.com » C++ is for Camry Says:

    […] The Director sums it up this way: To make it easier for people to become developers, they made it easier to write software. To deleterious effect. […]


wordpress visitors