Posts by John Smith 19

Re: There's legacy, and there's legacy

"All you get from passing the ACV tests is the knowledge that some version of the ACV tests were passed using some version of the compiler and some version of the runtime."

Ever wondered why embedded dev teams who do life threatening mission critical code are very reluctant to change their tool chain, including new releases?

Re: Who Do We Believe?

"For all those months, the DNS Server had operated as if the Mainframe connection was a Temporary connection that would Go Away as soon as the "Session" was complete.

6 Months Later, the Same Problem occurred AGAIN.

The Same ID10T had reset the URL in the Exact Same manner and not managed to rub together the two brain cells that should have Fixed the problem the First Time."

"Bodge" coders (and their counterparts "bodge" sysadmins) can "fix" anything.

They're just not very good at the critical thinking needed to ensure it stays fixed, by doing the necessary spade work.

By their work, so will you know them.

Unfortunately.

Re: There's legacy, and there's legacy

"RTL2 was another matter. It seemed to incorporate the worst features of C and Pascal, with none of their redeeming characteristics, and a buggy compiler to boot. I remember compiling RTL2 to PDP11 assembler, and then having to get the overlays right to fit it all into 48K. Building got easier when the output was M68K, the compiler was no less buggy though."

AFAIK RTL/2 predates C and is around the same age as Pascal.

One of Unix's lesser appreciated gifts to the world was putting YACC and lex into the hands of anyone who wanted them. Suddenly if you wanted a compiler (and where prepared to invest a relatively small amount of time) you could have it

Before that if you wanted a compiler it was fire up the assembler, and prepare for pain. I would suspect that RTL/2 (like early C) didn't really have a formal "standard" and at any given moment they either hacked the compiler to match the (desired) behavior or hacked the standard to formalize what the compiler could do (without massive surgery to its structure).

With "hilarious" consequences all round.

Keep in mind that the "classic" PDP 11s did not have memory management hardware (IIRC that came with the 11/780s and the VAX's ).

BTW the British Teletext systems ran on PDP 11's running RTL/2 code before being retired in a C rewrite.

Re: There's legacy, and there's legacy

"These days gcc and gnat mean that in general 'only' the code generating bits need to be target specific, other kind and clever people have done most of the rest in a target-independent fashion, and you can have it (source included) for free."

Unfortunately the problem is not that you have a good compiler (Which is maybe 1/3 the problem. You need versions of the Ada standard packages and some version of the defined Ada development environment, ideally tools using the DIANA intermediate language.

But you're still not done.

You have to prove it. That's where you need a certified Ada validation suite from someone like NIST or BSI to prove what your compiler does (and does not) compile meets the Ada standard exactly

Do I have to say you won't find one of these on the shelves at PC World?

It's about giving the customer the certainty that the customers code will do exactly what the standard says it will do (although wheather they realize exactly what that is is another matter).

I know. It's anal, it's bureaucratic, it's slow but it's how they roll.

And honestly if you're sitting in one of those metal tubes in the sky would you really have it any other way?

"Surely you mean an Extraordinary Rendition Flight."

Surely, citizen you know no such flight has ever entered UK airspace.

Re: User submissions need pre-check

"It's just they're heading to somewhere different to where they said they would."

Isn't that an alarm, not a systems crash type event?

Jovial mainframe compilers.

Looking a bit further I found IBM did supply a JOVIAL compiler under their "Type III" license.

IOW It was freeware.

No guarantee supplied. Use at owners risk.

Possibly not what you're looking for to crunch the code for you mission (and life) critical ATC app.

The commercial ones were hosted on it as cross compilers for things like the 1750A and Zilog 8002 (apparently the F16 was a design win for this puppy. Defense con-tractors. Crazy).

My recollection of JOVIAL was it was common on DEC boxes but as cross compilers to deep embedded kit.

"This would be a good opportunity to examine whether a central ATC is optimal when transponders + computers in each aircraft could, like a swarm of birds, create a self-organising complex system."

The trouble with all such brilliant ideas such as yours is they fail to account for all the stuff that's in the sky that does not have the room/power/aerial to mount a part of you "swarm."

That's better tracked from a central site (or rather a series of "central" sites, usually called "airports") and reported as a proverbial "unidentified flying object."

Re: There's nothing like state of the art hardware

"OS/370 and its descendants were running mission critical workdwide apps when you were in nappies boy. "

Could you say with an "Emperor Palpatine" voice?

For the more humor impaired in the audience I should say I absolutely agree. I wonder if this is the one they got off the FAA in the states, and does it still have valves in it, as their last one is reputedly said to have had.

Reading the story and the comments 2 things intrigue me.

1) It looks like it was a "bug" in the data that borked the primary, then it did the secondary, which tried to switch back to the primary. So what kind of data can't be sanity checked before its passed into the system (and of course will checking be added to the code now)?

2) I did not know a Jovial compiler for IBM mainframes even existed. Historically it's been for deep embedded systems like aircraft flight computers, ECM systems, radars etc.

Re: There's legacy, and there's legacy

"But I've not kept abreast of recent developments, so does any one know what is now being used instead of JOVIAL? (I'm a little surprised the wikipedia article doesn't mention this, so presume the obvious candidate - ADA, isn't quite so obvious or universally used)."

JOVIAL was big for real time control apps. IIRC it did the software for the B52, B1 and F15 at least (off the top of my head). The USN (being the USN) had something else (CSL?, something with a C in it)

I guess the UK equivalent were things like CORAL66 and RTL2 (ICI's in house computer language. No that's not a typo).

In theory Ada was meant to be the cure for this babel of DoD languages (including most of the assembler). But writing a full Ada compiler is a not trivial exercise and the DoD has a lot of odd hardware knocking about. and getting conversion tools to convert old-bonkers-software-originally-running-on-valve-processors has turned out to be a tad expensive.

The big surprise (for me) was having a Jovial compiler for an S/390 (or rather an S/360 as it would have been then). AFAIK when it's IBM mainrframe and it's real time it was assembler (which is how NASA got theirs to deal with the Apollo programme).

Yes that's an anorak.

".. not want to recognise other countries as equals or that there is a limit to American rule."

It's called "Extraterratoriality"

Yes US federal law really does believe it applies everywhere.

The usual standoff is that other countries think its a crime and the USG applies other sanctions to its suppliers to compel compliance.

In the case of ITAR for example, where if you use a UK part in a US satellite US law expects you to comply with ITAR for all sales of that product to all customers, even when you are a UK company.

It's hard to believe just how far US Federal Jurisdiction is up it's own a**e.

"They just happen to be owned by Microsoft Inc. in the USA."

THE PATRIOT Act applies.

Therefor All your data belong to USG.

"Personal information" to customers

"Business records" to business

Makes f**k all difference to USG.

Re: "...Orion is a horribly expensive capsule..."

" 'Cause that'll be cheaper and safer. I bet that the risk of failure might be about 1-in-10,000. And there's no way that each launch would end up costing $1.2B. "

You forgot the rest.

"And set a fixed cap of 1 Beeeelion dollars a year* on the budget (with no rolling over any underspend) and no allowance for inflation."

Thank you Caspar Weinberger of the (Nixon era) OMB.

*Enough to design a single new vehicle and a single new engine, which killed all the original 2 stage proposals. The winning design (1 vehicle + mother-of-all-RATO packs + humongous drop tank was a British aerospace engineer).