On Wed, Jul 22, 2015 at 8:02 AM, dwight <dkel...@hotmail.com> wrote: > I recall trading a board with one of the 432 family parts with you > years ago for a disk drive unit.
Thanks again! I've lost track of which 432-related hardware I got from whom, but I remember that some of it came from you. > I recall that everyone was thinking the military would switch to > ADA The part of the DoD that caused Ada to be brought into existence and mandated its use was focused on long-term cost and reliability benefits. Unfortunately for any given DoD contract, the contractor could say "we can get this done sooner and for less up-front cost if we do it in <non-Ada-language>", and get a waiver. It wasn't long before all DoD contracts were getting such waivers, so eventually they dropped the requirement entirely. > and the 432 was groomed for that. Intel marketing claimed that the 432 was designed for Ada. That's not actually correct. Intel had their own language in development, which in early form was called Prototype System Implementation Language (PSIL). When Ada came along, everyone believed it was the future of software, and that it was better to adapt to Ada than to try to push a proprietary programming language. They found that Ada would map tolerably well to the 432 architecture, though Ada didn't provide some capabilities that were necessary to the operating system, so Intel actually had an extended subset of Ada. Some features of the early 432 architecture were actually dropped, including coroutines, because they couldn't be supported in Ada. The DoD Ada validation requirements disallowed language extensions, so Intel sometimes referred to the extended Ada as SIL (System Implementation Language), though it used the same compiler and I don't recall there being any way to disable the extensions. > It was believed that more correct software could be created that > way. At least the generals bought it. > What wasn't known or thought about at the time was that the > more serious errors in released code was a misunderstanding > of what the code was suppose to do and not so much how it was > doing it( at least, once you remove memory leaks from the list ). Actually it's pretty well documented that programming in type-safe languages does result in more reliable code (as compared to e.g. C). It doesn't prevent all bugs, obviously, but it catches at compile time several classes of bugs that can only be caught at run time in non-type-safe language. > I'm curious, does anyone program in Ada? Even though the DoD doesn't require it any more, it actually does see a fair bit of use in the aerospace and telecommunication industries. When companies are building software for themselves, rather than for the DoD, sometimes they are willing to factor the long-term benefits into their decision-making. Boeing uses Ada for the flight control software of the 777 and 787.
