Re: [9fans] Easiest way to make a filesystem

["roger peppe" <rogpeppe@gmail.com>]

i agree that it's too hard to create servers for simple filesystems.

i've been wondering on and off for years what a "low-bar-to-entry" filesystem
creating library might look like, and my current thoughts go something like:

- it's the generality of the problem that makes it hard. 9p allows a great
deal of freedom in implementing semantics. there's not one design that
fits all patterns.

- that said, if we restrict the problem, we can make things simpler.
inferno's file2chan is an extreme example. 9pfile is an example at the
other end of the spectrum. something that deals with stackable filesystems
would be another example - but how much generality do you go for?
change contents only? change names? add new hierarchies?
change blocking behaviour?

- it seems to me that most of the time we want "natural" (i.e.
standard filesystem) semantics
everywhere we don't specify something different. this can be looked at a kind
of inheritance, the difficulty being that the inheritance cuts across many
possible aspects of the implementation - fids, qids, tags - all of which are
expressed in very different ways in code.

- perhaps there's room for a new "little language" here; along
the lines of yacc, maybe. but, how would we *want* to
express the specification for a file server?