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The Rise and Fall of Corba
ChelleChelle writes "Chief scientist of ZeroC, Michi Henning, has an interesting look at the story behind CORBA a once-promising distributed computing technology. Henning provides more than a brief history, in addition to several reasons pinpointing why CORBA fell short, focusing specifically on the OMG's technology adoption process itself. Most interesting is the final discussion on what we can learn from CORBA's decline, particularly in reference to web services."
CORBA might have been a great messaging infrastructure and all, but any corba websites I saw were confusing, over-diagrammed, impenetrably academic documents. Seriously, could you dumb it down a shade? Spare me your medical mumbo jumbo? Hello world apps?
CORBA is too complex, an overengineered attempt at creating a clockwork the size of Tokyo whereas a single wristwatch would have sufficed.
Yes, I have had to use it, unfortunately.
The OMG people are clever bunch, but why do they insist on making these superheavy monolithical monsters? Why not build interoperable but smaller things which you can grok immediately, almost via intuition?
Like you yourself put it indirectly via examples, developers like to develop systems which have the best supporting tools, systems which are the most intuitive and easiest to understand, systems which do not fight back when you try to do something, systems for which development is not an exercise in sado-masochism. So there's a design paradigm for you: make the APIs dead simple to use, and they will be used, a lot.
Nobody wants to hack around some big behemoth. It's about job ergonomics, really. If a chair doesn't feel right for your body, you don't sit in it.
CORBA always required holes in firewall, more complicated to setup(as mentioned in article), poor/no load balancing/fault tolerance mechanism/ maintainability(probably this was not meant to be there, but very important for an ecommerce setup), poor QoS (this improved in CORBA 3.0 after Douglas Schmidt's and others contribution), security (though iiop over ssl appeared sometime later, security mechanisms for ecommerce were missing, that could bring collaboration from unknown consumers/providers.)
SOAP/xmlrpc address some of these issues nicely, and might become defacto tools for business to business integration. I had only one issue with it. The protocol is too verbose.
My 2 cents.
hilarious
I can't find a citation for this offhand but the original author, whoever it was, deserves credit.
Imagine two superposed graphs, with time on the x axis. One is the rate of technical change. The other is the rate of adoption.
Standards activity needs to happen between the peak of technology development and the peak of adoption. Too early, and you standardize on immature technology that nobody will want. Too late, and the market has committed to somethign other than your standard.
Those two peaks in the charts are called the "two elephants". In fast-moving markets they move closer together, and the standards committee is "squeezed between two elephants".
Given that people were rushing to deploy immature technology for distributed apps, one factor in CORBA's troubles may have been that there was no room between the two elephants for a reference implementation or for nontrivial test deployments.
The problem with CORBA was mostly the technicalities and 'grossness' of the design. Yes I used the Java bindings, and it was just crap. All these "helper" objects and peers and stubs and junk. You'd compile an IDL, which was some hacked up C++ interface which wasn't even C++, get a buttload of Java classes that did not act anything like any other Java object on the planet. Lots of 'icky' exceptions. It just, for lack of a better way to describe it, had no style.
Try to teach CORBA to some normal programmer and they'll be thinking that creating their own wire protocol is probably going to be easier for 99% of the things they need to do. Seriously, you just don't look at CORBA bindings (for Java at least) and want to have anything to do with it. It's probably not so bad for C++ developers because they are used to a lot of noise and complexity, and they have templates and stuff to 'spray perfume' on CORBA and make it smell... better.
But seriously, when your technology drains the life out of any competent developer who actually likes to program then you know something is very wrong.
I'm not sure I agree with your chief argument, WRT latency in RPC calls. The answer to this is to use asyncronous development techniques as part of your IPC.
The increasing amount of network-related latency dealt with in everyday communication generally means that in any reasonable interesting application, there are often large numbers of blocking calls that take a variable amount of time to return. Threads in and of themselves are truly not the answer, except possibly when used sparingly as part of a non-blocking system. (as an aside, I've found that as a Python developer, working with the Twisted Python libraries was invaluable in my understanding of asychronous development techniques.)
With regards to the idea of function calls being an innappropriate abstraction for these mechanisms, I think the issue really depends on the implementation. The reasons I've used an RPC/IPC solution to communicate between processes (either locally or remotely) was because the various processes weren't closely related, and needed to have a common interface between them.
Making assumptions about implementation is an inherently bad programming habit, and has much farther reaching consequences. APIs would be essentially worthless if the developers made assumptions about how the work is done "behind the scenes". If you need intimate knowledge of the memory space of another process, it may be an indication to use process fork()ing to provide the same results.
anyways, my 2/100th of a dollar....
-phil
have you been seen on slash?
Some years ago I worked on a roll-out of some systems management software at a large company.
This software was based on CORBA.
It was hoped that by installing this software on every server and workstation in every branch nationwide (typically only around 3 to 6 machines per branch, although there would eventually be over 2000 branches netweorked), it would be possible to determine that all servers were working properly.
However the memory and CPU footprint used by the monitoring tools was immense. More than half of the RAM in the servers was taken up just by the monitoring software CORBA services, and the CPU load was also huge.
We also had serious problems with firewalls. Far too many open ports for anyone's liking.
Your comment is similar to many of the other comments in this thread. You're right that the CORBA specifications are HUGE and overly complex. But here's one of the great things about CORBA: it can be easily 'subsetted'. I use CORBA every day. I use 10% of it's features, and it is beautiful. If you gave me an exam about the esoterica of CORBA, I would fail, but for the parts that my company uses, it's easy.
BTW, most of the huge CORBA spec that we ignore is stuff that isn't part of the SOAP spec anyway; SOAP isn't really comparable to CORBA, SOAP is comparable to IIOP (the most popular CORBA wire protocol). Saying that SOAP is better than CORBA because it's easier/simpler is kind of like saying that MS Works is better than MS Office because it's easier/simpler (no, that wasn't a great analogy, but at least it isn't an automotive analogy).
Censorship is telling a man he can't have a steak just because a baby can't chew it. --Mark Twain