DISCLAIMER: These notes are from the defunct k8 project which precedes SquirrelJME. The notes for SquirrelJME start on 2016/02/26! The k8 project was effectively a Java SE 8 operating system and as such all of the notes are in the context of that scope. That project is no longer my goal as SquirrelJME is the spiritual successor to it.
The new year approaches.
The good thing is POSIX wise is that only two directories are required in root, and those are "dev" and "tmp". Because in Linux and BSD there are tons of directories in /, and stuff like /opt/ and /usr/. Very messy. In k8 there will only be 4 directories above the standard (since it is all Java) and those will be /local/ (This computer only), /network/ (Based on possibly a remote network location if this were a thin client using something like NFS, network would be that, otherwise /network/ is just the same as /local/), /user/ (the current user which is visible to the process), and /cards/ (sub directories inside of this contain individual users, if the user named "foo" exists they will own the subdirectory "/cards/foo", if a process is logged in as that user then /user/ will point to that directory.
Actually cards would be a bad idea, users would exist in their subdirectories as a users directory in /local/ or /network/. So there can be global network users which are visible.