LinuxWorld: Run levels revisited - What happens when linux startsJan 05, 2001, 07:11 (0 Talkback[s])
(Other stories by Joshua Drake)
"Linux is not like other operating systems such as MS-DOS and Windows 9x. Linux is its own beast. Quite a few would call Linux a UNIX clone, but I don't think that is fair to Linux. Linux is much more open and capable than most UNIX systems."
"When Linux starts, it calls a program named init, which runs all subsequent startup tasks. Those tasks include the multiuser environment, networking, and services such as sendmail."
"The run level is just that -- the level of functionality in which the operating system is running. The levels range from level 1 to level 6, and each level has a different degree of functionality. The run levels are specified within the /etc/inittab file. /etc/inittab is the master file in which the init program looks to execute its subsequent services. The very first services it executes are those located in the /etc/rc.d directory tree."