This is a good read. I believe that Steve Bourne (of Bourne Shell fame) implemented the file system in UNIX at Bell Labs but I may be mis-remembering that. He w

This is a good read. I believe that Steve Bourne (of Bourne Shell fame) implemented the file system in UNIX at Bell Labs but I may be mis-remembering that. He was also a big Multics fan. What is unsaid in this article is that nearly all file systems that are in widespread use today, started when "disk space" was a constrained resource. It is a very reasonable thing to ask, "now that stable storage space is much more plentiful, how might we design systems that are better than the current ones?" The ability to scavenge blocks to re-create state is a good example of that. One of the cool things about WAFL (the Write Anywhere File Layout) system that NetApp used (uses?) was that it's very design made snapshots 'trivial' since every write to disk was to un-allocated blocks. What that meant in practice was that the file system on disk was always sane. This was what let you pull the power from the box at any time, and assuming its non-volatile RAM was still available, it could always recover. Something that you could do with Intel Cross Point memory and a bunch of disks. Microsoft research built a number of interesting file systems, some more successful than others, which incorporated many of the ideas from Multics and other OSes. All in all, its a fun place to experiment.