Talk:Runlevel

On proposed merger with RL3

The only thing I have to say is that it's nice to get a quick definition if you're just curoius. The link to runlevel is there if you need more info. --AlanH 22:29, 28 January 2006 (UTC)

Ubuntu and Upstart

While ubuntu does use upstart, runlevels still play an important role. Single user mode is still accessed with "sudo init 1" and startup/shutdown scripts are placed in respective rc directories.

The section IMHO should say ubuntu uses upstart and its init levels are the same as debians (as it did before).

I would do it myself but I am unsure of how accurate I am and I am not knowledgeable enough to talk about init. --Sish 04:36, 29 May 2007 (UTC)

Purpose of run level 4

Run level 4 is for "turnkey" UNIX systems, such as AT&T's telephone switches. In a modern context an Pizza shop application would boot into run level 4. If the system is swapped out for diagnosis then the programmers can boot the machine into run level 3 or 5 for the standard multiuser development environment. I've got an old Bell System paper on System V Init which describes this, I'll see if I can find it.Gdt 12:53, 15 November 2007 (UTC)

Discussion about merging runlevel and init

I don't think they should be merged even they are so related they are not the same. Callmejosh (talk) 08:01, 6 September 2008 (UTC)

Runlevels a, b and c

What about runlevels a, b and c? They're called "on-demand" by man inittab(8), but the manual doesn't clarify what they're supposed to be used for. Does anyone have any documentation on those? --Wtrmute (talk) 19:05, 31 July 2009 (UTC)

To quote from a System V administrator's manual from 1982 - look for "INIT (1M)":

Telinit, which is linked to /etc/init, is used to direct the actions of init. It takes a one character argument and signals init via the kill system call to perform the appropriate action. The following arguments serve as directives to init.

...

a,b,c tells init to process only those /etc/inittab file entries having the a, b or c run-level set.

and to quote from a System V administrator's manual from the same manual set - look for "INITTAB(4)" (yes, it's silly that it's in the user's manual; I guess they didn't bother having a separate "4M" section, in the administrator's manual, for files used only by administrators):

There are three other values, a, b and c, which can appear in the rstate field, even though they are not true run-levels. Entries which have these characters in the rstate field are processed only when the telinit (see init(1M)) process requests them to be run (regardless of the current run-level of the system). They differ from run-levels in that the system is only in these states for as long as it takes to execute all the entries associated with the states. A process started by an a, b or c command is not killed when init changes levels. They are only killed if their line in /etc/inittab is marked off in the action field, their line is deleted entirely from /etc/inittab, or init goes into the SINGLE USER state.

So those are for "one-shot" running of processes from init. Guy Harris (talk) 19:34, 23 March 2019 (UTC)

RL 0-9

Which OS has runlevels 0 to 9? --Vssun (talk) 08:14, 20 August 2011 (UTC)

I have added runlevels to my systems so I have 0 to 8. 81.228.219.220 (talk) 16:55, 3 June 2016 (UTC)

Arch Linux runlevels

With Arch fully switched to systemd, it no longer has runlevels by default. — Preceding unsigned comment added by 146.145.85.49 (talk) 23:50, 6 February 2013 (UTC)