Please provide a short (approximately 100 word) summary of the following web Content, written in the voice of the original author. If there is anything controversial please highlight the controversy. If there is something surprising, unique, or clever, please highlight that as well. Content: Title: Ask HN: What are some good resources for learning about low level disk/file IO? Site: I've been messing around with writing a toy database for fun/learning, and realised I've got a fairly big gap in my knowledge when it comes to dealing with performance and durability when dealing with file reads/writes.

Example of some questions I'd like to be able to answer or at least make reasonable decisions about (note: I don't actually want any answers to the above now, they're just examples of the sort of thing I'd like to read in depth about, and build up some background knowledge):

  * how to ensure data's been safely written (e.g. when to flush, fsync, what
    guarantees that gives, using WAL)
  * blocks sizes to read/write for different purposes, tradeoffs, etc.
  * considerations for writing to different media/filesystems (e.g. disk, ssd, NFS)
  * when to rely on OS disk cache vs. using own cache
  * when to use/not use mmap
  * performance considerations (e.g. multiple small files vs. few larger ones,
    concurrent readers/writers, locking, etc.)
  * OS specific considerations
I recall reading some posts (related to Redis/SQLite/Postgres) related to this, which made me realise that it's a fairly complex topic, but not one I've found a good entry point for.

Any pointers to books, documentation, etc. on the above would be much appreciated.