- /etc — system-wide configuration files
- /bin — essential binaries needed for single-user mode (e.g. ls, cat, cp)
- /sbin — essential system binaries (e.g. init, ip, mount)
- /boot — bootloader files (e.g. kernel, initrd)
- /lib — libraries essential for the binaries in /bin and /sbin
- /var — variable data (logs, spools)