This is extremely myopic. there is not a 1:1 correspondence between using asynchronous io and using one thread per file. Asynchronous io lets you dodge thread

This is extremely myopic. there is not a 1:1 correspondence between using asynchronous io and using one thread per file. Asynchronous io lets you dodge thread safety mechanisms like semaphores. Not all of us are trying to write a webapp or whatever, some of us just need to load a lot of data from several descriptors without serializing all the blocking operations. >Not every IO operation can be performed asynchronously though. File IO is perhaps the best example of this (at least on Linux). To handle such cases, languages must provide some sort of alternative strategy such as performing the work in a dedicated pool of OS threads. Uhhh this is just wrong file io can definitely be done asynchronously, on Linux, and without language support.