James Webb Telescope will run a proprietary JS interpreter by a bankrupt company
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Edit: Thinking about it, I have read that Lisp was used for early NASA missions because of its ability to be rewritten in-place, which JS mostly shares. Still, JS has so many weird quirks and so easily throws exceptions. And it can't be very fast at processing images. Maybe it's only used for high-level control logic?
Why not?
I doubt NASA wants to do much image processing on-board in the first place. Mostly just lossless compression and maybe some thumbnailing, if they can't download everything.
- undefined vs null vs empty
- the pile of weirdness that is ==
- the other pile of weirdness that is implicit truthiness/falsyness
- NaN's many fun qualities
>Building Lua should be straightforward because Lua is implemented in pure ANSI C and compiles unmodified in all known platforms that have an ANSI C compiler.
One thing that always stuck out to me though, were the counters in the room. We'd leave one in the test chamber as close to the parts as possible, to get more accurate readings. Those little counters always borked out. The 7-part digital counters would just flicker and dance about in the rads. These 'hardened' counters would always fail first, and a lot sooner, than the CPUs.
I was just doing the dosing, not the code in the CPU. But if those very simple counters were fried well before the more complicated CPUs, and they were not in the full thrust of the radiation, then I can't imagine what those guys were doing to mitigate their code in that rad-soup. It was very impressive.
This is good to hear though. JS is a great entry level scripting language and makes sense for applications like this where you just need to get a specific job done rather than worrying about everything else that comes with code being the actual product.
If prior longevity is used to predit future longevity it’s an interesting thought exercise to think of how you’d write software. If projected longevity were my concern for a system, I’d almost certainly want things written in C or C++, maybe Ada. If I wanted high level scripting, I’d probably embed a Scheme.
Also previous discussion on HN: https://news.ycombinator.com/item?id=13009598
http://www.flownet.com/gat/jpl-lisp.html
And of course, JavaScript having its origins as a more marketable syntactic overhaul of Lisp for in-browser scripting, it's not hard to see how we end up with JS on the JWST for many of the same reasons.
Like others, I tend to idealize space tech from a distance and imagine it using technologies that are across the board better, cooler, more pure than anything that stays on the ground. While the need for extreme reliability does change things a lot, it turns out most of the same forces that guide software selection anywhere else are at play there as well.
FWIW, they are sending observation sequences marked up as some custom JS, and an onboard interpreter will turn those into C&DH sequences and spool them out.
That decision seems arbitrary, given most onboard executives use a ... more standardized markup lang for sequences.
https://www.google.com/url?q=http://www.stsci.edu/~idash/pub...
https://mobile.twitter.com/alteredq/status/80085890885198233...
It’s unfortunate and unnessecary.
Sequence scripts are written in js.
Execution of sequences, hardware control, resource management, and everything not sequence markup is not. The sequences are not flight software (imho), but the interpreter is.
They wanted a scripting language, likely to make updating stuff around the craft easier, it's high level control so low level languages don't make that much sense.
You'll likely see Rust and other modern languages in about 15 years or so flying into space.
JavaScript is small, but then again - you need to ship the interpreter.
Not sure about maintainability either - static typing really helps with that.
The safety you mention is that js runs in a sandbox (and e.g can't wipe your hard drive), but this is a feature of browsers, not the language itself.
All in all I find it hard to believe they wrote any critical parts in js, and I'd also guess it's possible to replace the currently deployed scripts should they fail.
On the point about inconsistent state: if your JavaScript program is doing something important but then dies because of a bug then maybe the interpreter was left in a consistent state, yes, but what it was doing was not. This is safe how?
For bug prevention I like defensive programming, checking for "impossible" conditions that should never happen. And always exit if the unforeseeable occurs.
The most effective way to prevent bugs though is probably to keep that program small and comprehensible, and that's easier with a high level language.
The static type checking is just one of many ways to prevent bugs. Personally I rather want the dynamic features. And I add checks at critical intersections, with human friendly errors. And do other automatic tests.
What I was pointing at more is that there are ways to prove for a program (even for C I've heard) that your program has no bugs, and also that whatever loop it has it always runs at some "Hz" level at most - which makes this a good fit for controlling something efficient in real-time. As far as JavaScript goes it seems it's mostly meant to run at the edge where it's fine to fail mid-way and where you have time to wait for a restart. How much time is enough time is, I guess, very dependent on what is being controlled, and perhaps for a telescope restarting is tolerable.
I write haskell these days and I can say that for the most part of the code I don't check anything since the type checker does it for me (once, at compile time). And if it compiles I can be fairly sure that there are no bugs. It's only at the edges where I talk to external APIs and/or parse json where I get errors and need to handle them in some way. There are of course bug sources left after types, but a huge part of it simply doesn't exist.
But I do understand how JavaScript can be a good choice if errors are tolerable, since it's fast to prototype in, and also, as a language it's easy to pick up, tons of resources online, plenty of developers who already know it etc. But I'd still maintain that safety isn't a property of the language itself, but more of the infrastructure it runs on.
http://ttendency.cs.ucl.ac.uk/projects/type_study/
So, i don't think, that Haskell really helps not to introduce logical bugs. And, as to my experience with Haskell, such bugs really hard to detect (somebody else's code is hard to read; especially, if the code is based on categorical abstractions, not widely known, or on well known abstractions, but in pervasive ways), and harder to fix, because of the amount of code that should be rewritten.
And of course, with Haskell there are always undetectable system errors, like consuming all of the system RAM by quite simple loops. There are no internal tools in the Haskell's semantics, to detect such situations, catch them and treat sanely.
And usually strict type systems are bad in providing such a system reflection semantics to the languages. You always should fallback to some kind of external interpreter, like IO, which may be integrated in the language with extremely hard to detect errors. See, for instance, the bugs in FSCQ http://css.csail.mit.edu/fscq/
So, Haskell, i think, is not the best choice for spacecraft programming.
And one should not rely only on the type systems and verification (remember Arian 4 or Deep Space One stories). You always need to test exhaustively. But if so, why not to use simpler language? At least it might have less bugs in its interpreter/compiler.
But in reality, that's fine. They'll muddle through on something like this, finally getting it to work through endless tinkering, and it'll be fine.
Remember, the entire internet now pretty much runs on this premise. And it's fine, right?
TypeScript, for instance, is a much better development experience in terms of language constructs, but that only makes the package management situation stand out more.
I have a somewhat fuzzy definition. "A programming language that has more 'intent' to it."
For example, Rust. The designers had definite ideas about what they were creating, noted the trade-offs, and implemented features based on those decisions.
You can say that about lots of languages - Java, C#, Swift, or if you need to go back 10 years, Java <g />, C, or maybe even Python.
JavaScript on the other hand was cobbled together in a few weeks by some poor fellow who was under impossible deadlines. And it shows. We've all seen the "Wat" video. Programming in JavaScript is a minefield of bizarre phenomena. Function scopes as namespaces. Nutty math. It succeeds in spite of itself because, a. It's rarely used for anything truly important, and b. It runs on the most popular run-time environment on the planet.
Not that you can't do great things with JavaScript. But just about any other language would have been preferable.
No, they don't. All of Wat's complaints against JS, in order of presentation:
> [] + [] ; JS: '', Python: []
Python uses + between arrays for concatenation, just like strings, which I think is reasonable. JavaScript does random crap.
> [] + {} ; JS: '[object Object]' (that's a string, not an object), Python: TypeError.
Again, Python's output here is reasonable, JS's is off the deep-end.
> {} + [] ; JS: 0 (the integer) Python: TypeError
Again, Python's output here is reasonable. JS appears to demonstrate that + isn't commutative, but that's too rosy a picture: in this case, + actually is commutative, as ({} + []) and ([] + {}) are the same string, but without the parentheses we get 0. Yes, the lack of parentheses changes the value JS emits.¹
> {} + {} ; in Wat: NaN, in Chrome/Node: '[object Object][object Object]', in Python: TypeError
Similar to before, Python errors out on the garbage, JS just keep computing ever more insane values.
> [longer example, but boils down to "wat"+1 doing something and "wat"-1 doing something else for comedic effect.
Python TypeErrors on both of these.
Python certainly has its own warts, but they are not as ridiculous as the warts that JS carries around.
¹AIUI, {} + [] is parsed as empty code block, implicit semicolon, unary plus, empty array. The parentheses force the grammar to evaluate the entire thing as an expression, so ({} + []) parses instead as a parenthesized empty object, binary plus, empty array.
> cobbled together in a few weeks by some poor fellow
It was. And then all work has stopped on it, right?
Prototypical inheritance is actually not a bad choice.
The event loop also stood the stand the test of time, it's a great choice for IO heavy environments like the web is.
The weak type system made it possible to bang out code really quickly without much thought thus making it very beginner friendly. Most of its issues can be traced back to this.
every time like clockwork
I think you mean the Web.
That probably played 0 role into this. When the project was created, about 20 to 15 years ago, people put in the design specs. The language selection was JS, Python 1.5 (1.5, not 2, not 3, 1.5, released in 1999) and a custom script language.
NASA decided for JS because Python used more memory.
The JS that is being run is essentially IE6 or IE5-level, so none of the modern features introduced in IE8 and forwards that make it all so easy.
I'd expect more modern variants of JS (TypeScript) or even something like Rust to make an appearence in 15 years or so. Atleast for these kinds of missions.
> 2. An attempt was made to port each scripting engine to the VxWorks real-time operating system on a flight-like Power PC by embedding it into a payload flight software application. TCL was dropped from the study when it could not be successfully ported to VxWorks. JavaScript, Python and G-script were successfully ported and a series of tests with prototype flight software applications were run in order to rank them against the success criteria.
https://www.scribd.com/document/407354589/Event-driven-James...
(My guess: no, but that happened well before my Python initialization.)
Back in the early 2000s, before Numpy was a thing, STScI developed an image-file-reader for Python called PyFITS, and an underlying array extension to Python that allowed multiple base types, slicing, etc., called numarray (e.g., see https://scipy.github.io/old-wiki/pages/History_of_SciPy.html). In some sense, STScI might have been expected to prefer Python to JS.
I've done C, C++, C#, Java, Basic and Python for a living in the past and I always make rock solid software. JavaScript is by far the most productive programming language that I've used to do this.
People who think there's such a thing as an objectively "proper" programming language that they haven't even named are actually the problem with this industry, not JavaScript developers.
Everything else you claim is suspect because you said this.
Besides that, if you think that there are no people out there who can consistently write solid software, well...you're just flat out wrong. (And if you think you can't find them on HN, well wrong again...)
Honestly, if you've always delivered rock solid software, you're some sort of mythical creature.
Yes, anyone who's ever done a slight bit of bragging, even if it's actually true, is automatically and forever, completely lacking developer self-awareness.
> Honestly, if you've always delivered rock solid software, you're some sort of mythical creature.
There are whole agencies full of people that do it. But I get it, the thought that it's somehow impossible probably makes most software devs feel better about accepting their own mediocrity.
I love how everything is so black and white to HNers. "If you've ever bragged, you can't be telling the truth." or "If you use JavaScript, you're not a real programmer."
It's very comical.
I've seen great cathedrals of frameworks and patterns being built by smart experienced guys over few years, which ended up in quite a bit of mess at the end. Add a junior or two and see what added value they bring
Oh, great, a space telescope run like the internet. Now every 2-bit remote galaxy out there is going to be making toxic comments about the Earth and human civilization as we know it. Be careful not to mention things like white dwarfs, or you'll be in for it from all sides.
Thanks JavaScript. Way to ruin the night sky for all of us.
I've been coding since I was kid, and professionally for over 20 years. I've used a few different languages, in a few different contexts, but Iv'e done JS in front/backend for the last 7 years or so and I find statements like these utterly tiresome. Sure, there are lots of naive JS devs...but I can say the same for Java, or any other language that is "a proper programming language". A lot of JS code is written to optimize for things that may it not seem like "solid software" - but I've seen a lot of terrible "solid software".
When we collectively realize that our industry is so young, that the best practices of yesteryear are often now viewed as mistakes (and that the practices from before that were maybe the right idea...), and that we really DON'T KNOW the correct answer, maybe then we'll stop loving to hate on people who are doing work that we might not do so well at if we tried it.
I don't know your intentions in saying what you said, but in general there is a LOT of smug looking-down on web development in general and JS development in particular. Arrogance is not a good look, and derision is worse. The industry has improvements it can make, certainly, but this is something true of us all, not something restricted to one sub-group while everyone else is doing thing The Right Way.
That said JavaScript has a number of the same problems as PHP and pointing this out should be equally acceptable as pointing out issues with PHP[1], and while I'm impressed that it was created in three weeks and impressed with the JS community we shouldn't pretend it is a very well designed language. People being productive in JS is pretty much a result of an amazing ecosystem, not because of the language.
For a very simple example of what JavaScript could have been, look at Typescript: anything you can do in JS you can also do in TS. In fact, "porting" from JS to TS is as simple as changing the file extension.
Yet except for the need for transpiling TS is massively easier to work with and can eliminate whole classes of problems when used correctly.
Source: Have programmed and maintained others creations in JS and later TS.
[0]: https://eev.ee/blog/2012/04/09/php-a-fractal-of-bad-design/
[1]: I also have programmed my fair share of PHP code. It doesn't have to be bad. But I'll happily admit that it isn't the prettiest or most well designed language I know.
No. I will just pick a good ecosystem and the language it was built around and be happy instead of proving that you can build a skyscraper out of feces by producing steel via nuclear fusion.
That said, I really enjoy Common Lisp for being compiled (good performance versus interpreted) and the speed of compiling (compiling single functions at a time) so you get the same time-to-execution as your interpreted languages. Better, actually, if you change the function definition in place when you hit a condition.
EDIT: I hit submit before finishing my thoughts.
C++ isn't that bad. 5+ minute compile times can be tightened down if you have a good structure for your codebase. And if it remains at 5+ minutes, that's what unit testing is for (shouldn't need the whole build to execute) along with a build pipeline. Submit the change and get results after a few minutes. Distcc and other systems can also aid for the really large projects. Another factor to consider, to test that interpreted (presumably dynamically typed) program you have to have more tests than the C++ program needs. Static typing (even though I have issues with C++'s type system, it's still ok) covers a lot of the areas that you have to manually create tests for in dynamically typed languages
Not the best example, considering that PHP has done its time as whipping boy. I've never been a PHP dev and I did my share of trash-talk against PHP instead of learning about the aspects that I could learn from.
My problem isn't that it's "unacceptable" to point out issues - it's that people aren't doing so CONSTRUCTIVELY. Instead, it's about finding the lesser social class to dump on freely.
For example - I have serious concerns/doubts about typescript and how it props up a tool-enhanced crutch for programming-as-communication that ultimately leads to lower-quality code. You would likely disagree and would raise your concerns about JS without TS. We can have a lovely conversation comparing points and, while it's probable neither of us is convinced by the other, we both walk away with a better understanding of the perspectives of others and impacts of code choices.
OR we could imply that JS isn't a "proper" programming language, and thereby JS devs aren't "proper" programmers and we can pat them on the head and tell them to run along and play.
Back when I was doing a lot of Perl dev (before my Java days) I noticed that the weaker Perl devs would hate-on Python (and the reverse), while the stronger Perl/Python devs would hang out with the stronger Python/Perl and compare notes. It took me a while to figure out why that made sense. The two communities had a lot of explicitly different philosophies, yet were really able to learn from one another and occasionally both languages improved as a result.
If JS isn't someone's preferred approach, that's fine...but that doesn't mean they are "lesser". They're _different_, just like different problem domains are _different_. That doesn't make them immune from criticism either, but I'm far more interested in those looking to broaden their views rather than broaden the reach of their current viewpoint.
Reading your comment now and rereading your comment I realize you were defending Javascript programmers, not the language. (I guess we'll have to disagree about JavaScript the language :-)
I agree we shouldn't attack programmers because of language choice. And I am happy that I pointed out that I am amazed by the JS community as it hopefully shows that I wasn't trying to attack anyone.
As for the language - JS definitely has its warts and its holes. It's not a language I love, but it IS a language I greatly enjoy developing for. Then again, I thought Perl was a great language (albeit with its own warts) so my views are fairly unconventional. Definitely though, I tend to think that languages fall into a more complex graph than just "better" and "worse", or even "better at X" and "worse at X".
This is NASA we're talking about. For a satellite. There will be no muddling, or tinkering.
Nasa isn't in the market to hire any old web dev you know. This is rocket science.
Edit: On second reading you may not be a serious as I first thought :)