Veering off topic here- seems like the original issue is taken care of, and I'm glad there's a workaround in sight that's lightweight.
Anyway, I've been in enterprises where NFS is in wide use, and I also used a boot-from-network diskless server that had /tmp mounted via NFS... and as for "One can use different filesystems for different files" of course Sys::Filesystem is path-specific, I only mentioned $OSNAME to reference something even more fundamental to the core than a core module.
