This article recently made the rounds on HackerNews: http://www.cs.columbia.edu/~vatlidak/resources/POSIXmagazine.pdf
It calls out IPC and async I/O as two particular areas where POSIX doesn't cover very much. I'm curious whether Redox folks have written about plans for those things anywhere? I noticed this issue discussing IPC, so maybe that's a good place to follow along right now? I didn't find a similar issue for async I/O though.