Servers: File system (namespace server?) Network Exec server User management Terminal server (interface server?) X server create windows by writing to files Each user can have as many user ids as they want, can merge them, can assign any of them to files, etc. User controllable: FTP file system Exec server nfs file system random signature generator (meh) - controls one file ~/.signature device file system /dev/(hd0,0) /dev/(hd0,0:hd1,0) One device spread over two partitions cat /dev/{gzip{slice{fd{0},1024,5}}} > ~/floppystart.gz Takes 5 KB of data from the floppy, compresses it, and saves it as floppystart.gz (powered by device file system) /dev/gzip{slice{/dev/fd{0},1024,5}} /dev/gzip(slice(/dev/fd(0),1024,5)) translators/ports