alt Hacker News> Modularity abstraction aspires to hide the interleavings and present operations as if they were atomic. Its goal is to make the module easy to use, but in doing so it forgoes exposing concurrency or efficiency opportunities.
> In stark contrast, the modeling abstraction is about identifying what should leak and leveraging it! It exposes the fine-grained actions and orderings, and proves that invariants hold despite the interleavings. The payoff for this work is to harvest the maximum safe concurrency from the system.
I guess I don't understand the argument here because those just sound like two different flavours of the same custard to me; the difference is just the balance of work you're doing on each side of the interface, and that decision depends on use cases specific to the project.
This feels more like it's making a point about system design? Abstraction is abstraction - you can apply it at different levels within a project, and a big part of building skills in software development is in learning to zoom in and out and nail the abstraction at each stage, but ultimately you're doing the same thing over and over. I don't personally think we need categories of it.
> I guess I don't understand the argument here because those just sound like two different flavours of the same custard to me; the difference is just the balance of work you're doing on each side of the interface, and that decision depends on use cases specific to the project.
It is two different flavours. One is about interconnecting things, and the other is what you interconnect. What TFA called modelling abstraction seems to be the primitive ideas that goes in building more complex systems (which it calls Modularity Abstraction). Something like a String is not a primitive, but rather a combination of the idea of Character and List are. Just like you can go from a disk (a pure array of bytes) to a file system (in the unix world, a tree with nodes of metadata). The primitive here are Array (existing) and Tree (target) and with them you build a modular system (The file systems) that transform ones into another.
So yes, both are abstractions, one is about identifying primitives, and the other is about combining them.