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by lelanthran 1090 days ago
> In my 25+ year career I haven't seen it in use anywhere. I only ever encountered it while getting my CS degree.

Too bad you didn't join the company I left in the 90s. It was used in production.

I learned about it in my CS degree too, and (because I was a fulltime dev at the time as well as a part time student) I went ahead and used it at work[1].

From what I remember of using it in production, the only difficulty I had was in sourcing a free ORB (server software) that supported inter-ORB routing so that I could load-balance.[2]

My employer eventually shelled out a small fortune (it was the 90s, we were drowning in VC money) for something from, IIRC, IBM[3] that ran on Sun Enterprise Servers (another small fortune).

My experience with CORBA was GREAT! I mean, compared to the way we do it now with browser tech:

1. I could use any language to write the client software, not limited to only Javascript.

2. Making a server call from the client was transparent. It looked like any other function call, unlike how it has to be done now using promises/futures or callbacks.

3. The tech supported exceptions which were also transparent to the programmer. In C++ you could do the following and it would work as expected.

    try { myObj->foo() } catch  { /* ... */ }
4. It was all strongly typed; if you used an argument with the wrong type you'd get either (in compiled languages) a compilation error or (in Interpreted languages) a runtime exception before the call is made.

5. Developer velocity was great. I wrote my object specification, the tools generated both the server-side and the client-side wrappers, and all I had to do was call them.

[1] I was young, still in the phase of resume-driven-development.

[2] I used a free ORB written in C++ called either Mico or Micro; I don't remember the specifics.

[3] Maybe Sun, I'm not sure.

3 comments

> Making a server call from the client was transparent. It looked like any other function call

That is a very bad idea and one of the reasons this kind of thing rightfully died out.

Because a server call isn't like any other function call. It has orders of magnitude higher latency, and additional failure modes that you actually have to take care of.

It shouldn't look like any other function call.

> It shouldn't look like any other function call.

I'm sorry, This is the stupidest thing I see commonly repeated in public discourse about software.

Every single distributed application I've ever worked on in my 30-year career (including working for multiple companies you've heard of) wrapped remote calls in something that looks like a normal function call. It doesn't matter if your low-level RPC stub throws RemoteException or returns RemoteError, somewhere up the call stack someone has wrapped this into a simple method that looks like this:

    doSomethingUseful();
In real life, you make a call to a function and you live with the consequences. If you're lucky, the docs let you know the performance and failure characteristics. If not, you make some assumptions. When those assumptions are wrong, you spend some time debugging and profiling.

Adding a bunch of syntactic noise to the callsite doesn't help. The first thing any competent programmer will do is abstract your noise away in convenience methods. Because 99% of the time, it doesn't matter that your call is remote.

Take a look at your own codebase that makes client REST calls to some other service - you may hand-wire a bunch of http calls, but somewhere up the stack there's a function that hides the http mess. Everything below that function is accidental complexity.

> Every single distributed application I've ever worked on in my 30-year career (including working for multiple companies you've heard of) wrapped remote calls in something that looks like a normal function call.

This isn't a problem as long as the returned value provides the right failure semantics (like futures). The problem with trying to encapsulate the network is that deep call chains lead to cascading failures for problems that are common in networks (partitions, latency, etc.). These failure modes also lead to more pervasive use of timeouts in deep call chains, which then introduces non-determinism, which itself makes issues impossible to debug.

This is also nonsense. 99% of the time these failure modes are irrelevant. A remote call fails, the error propagates up the call stack, and someone gets an error message. Just like any of the thousands of other things that can produce errors in complex systems.

In the rare case you need to harden a particular call, you add caching or retries or whatever other logic fits your use case. It matters not one bit whether you're using futures or synchronous rpc stubs. Actually it does - synchronous code is easier to harden because it's easier to reason about.

Even javascript added await because it's better to pretend that async code looks synchronous. The failure semantics of "throws an exception" are just fine.

> A remote call fails, the error propagates up the call stack, and someone gets an error message.

Uh-huh, but did the message actually get through? Can they safely just retry? These are very uncommon failure modes on local systems but very common on networked systems. Without a proper stateful abstraction beyond just "procedure call", like a promise, you can't address these failure modes properly.

> In the rare case you need to harden a particular call, you add caching or retries or whatever other logic fits your use case

Which now makes your system nondeterministic like I said.

> Even javascript added await because it's better to pretend that async code looks synchronous

Yes, linear code is easier to read. I don't see what this has to do with anything. The use of promises and await indicates a possibility of failure semantics that would otherwise not be apparent in the program's control-flow.

Yes, you can superficially make this look like synchronous code, but it's not synchronous code.

> Uh-huh, but did the message actually get through? Can they safely just retry?

...

> The use of promises and await indicates a possibility of failure semantics that would otherwise not be apparent in the program's control-flow.

They don't, though. They don't indicate if the message got through. They don't indicate if you can safely retry. Their failure mode is exactly as opaque or as transparent as synchronous calls.

The reason for their existence and mandatory use in Javascript is due to a deficiency of the platform (single thread, so all synchronous calls block).

If the platform was better they would never have existed.

> you can't address these failure modes properly.

Again, total nonsense. There's nothing special about a promise. Whatever logic you can build on promises is easier to build synchronously. Everything that applies to building distributed systems applies whether you use rpc stubs or promises. Promises are just noisier and harder to reason about.

> That is a very bad idea and one of the reasons this kind of thing rightfully died out.

I agree, but, like everything else that is a bad idea, naming conventions help.[1] Namespacing helped too.

I used naming conventions to ensure that network calls looked different, and namespaces that kept network objects in their own module.

[1] Right now we rely on naming conventions in most codebases to differentiate between #define'd literals and variables (C), between constants and variables (Java), between variables and methods (Kotlin, Java, everything else), between interfaces and classes (C#, C++, everything else too, probably), for everything in Python (pep8).

Using naming conventions to identify remote calls is no different than using naming conventions to identify interfaces.

2: You can do HTTP/Json requests "transparently" just fine, it's an implementation issue. The issue is if you're doing that from JS you're blocking the only thread and even in a server/desktop language like Java, C# or C++ you're going to be blocking the entire thread and possibly degrade performance. This wouldn't have been any different with CORBA (But people ignored thread cost issues back in those days).

3: again implementation issue.

4: swagger/openapi will help on the compile side (sadly not runtime with all languages but again, language/impl issue)

5: generators are still a thing and available if you look.

For each thing you list as an implementation issue, it's a problem.

My complaint is not "these things don't exist now", it's "they're not part of the standard". For each "it's an implementation issue", you have multiple incompatible competing mechanisms. With CORBA, while the standard was large and stupid, the very basic thing (make an RPC call, get the response and handle any errors) was supported by the standard in a non-ambiguous and practical way.

So, yeah, the fact that something that was available in the 90s is now available depending on implementation is the problem.

The first 3 is every RPC API which is not complete dreck.

4 and 5 are limited to the schema-based ones.