Thursday, 11 February 2016

Notes on Concurrency and Distribution: Programming Languages

In my previous posts, I had mentioned programming languages multiple times as the right place to implement solutions to concurrency and distribution. I'm going to elaborate on this a bit more.

A programming language is a tool which provides powerful abstractions to build software systems. Much of our approach while building systems is guided by the languages that we know or use. For example, there is a significant difference between the people who use a functional language vs people who use an imperative language.

Functional programmers seem to have a data driven approach i.e, they think about how the input data can be transformed to generate the desired output. They use functions as black-box entities to transform the data, and the program as a whole is a function. And, by definition, a function must return the same output every time for a given input - this encourages the programmer to write stateless programs i.e, the programmer doesn't use many intermediate data structures which represent the current state of the program's execution.

While on the other hand, imperative programmers approach the problem as a sequence of steps which need to be performed on the given data to generate the desired output. Here, the programmer often achieves this by storing the result of a certain sequence of instructions in an intermediate data structure, which can further be used in the remaining sequence of instructions.

The key idea, is to realize that programming languages, to a large extent, affect the way programmers break down a given problem into sub-problems. More details on this specific topic can be found on this paper.

This is precisely the reason I (and many more people) think a programming language is the most effective way to provide abstractions to effectively build concurrent and distributed systems. But this is also where the problem lies, as most widely used languages are designed primarily for sequential computation and merely "support concurrency" (let's not even get into distribution).

It is not that these languages cannot be used to build distributed systems (people have done that), rather, it is very difficult to effectively build and maintain distributed systems in such languages (the same people will tell you that). It would be great to have the intricacies involved hidden from the programmer and implemented (and hence natively supported) by the language itself. When was the last time you said "Oh, I forgot to deallocate that memory block" ? (I feel sorry for you if you have an immediate answer).

More on the specifics later.

p.s. Yes, Erlang folks, I hear you.

2 comments:

  1. These notes on concurrency and distribution is so helpful for all the programming language students.These would be so much supportive for them during their practice of programming.

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