/sbinbinaries essential to system and all users/usr/sbin/system admins binaries/binbinaries used by system and all users. cannot do without them./usr/bin/non essential users binaries/etcconfig file for system eg: /etc/init.d/ has startup config scripts/homeeach user gets a directory in here/roothome directory of root user/libshared libraries required by system programs (kind of like windows .dll files)/varspooling data, stuff always being written to and read from it