Part of the usually invisible file system structure that describes a file, such as its ownership permissions or file size.
The program that is automatically run after the kernel has finished loading, and therefore early in the boot procedure. It’s responsible for effectively starting the operating system.
Collection of startup scripts that make up the components of a run level. Found under the SUSE Linux systems at /etc/init.d/. Symbolic links to selected init.d scripts are contained in folders within /etc/init.d that are named after run level numbers, such as rc0.d, rc1.d, rc2.d, and so on.
Initial RAM disk; system used by the Linux kernel to load modules that are essential for the kernel to be able to boot, such as disk controllers.
Now deprecated component of version 2.2 of the Linux kernel that allows the creation of network security setups, such as firewalls or port-forwarding arrangements. Note that some distros still prefer to use ipchains. See also iptables.
Component of versions 2.4 and 2.6 of the Linux kernel that allows powerful network security setups. Chiefly used in the creation of firewalls, but can be used for more elementary arrangements such as network address translation (NAT) routers.