Open main menu

CDOT Wiki β

Changes

Temp OPS235 Lab 1

3,197 bytes removed, 15:51, 11 January 2012
no edit summary
{{Admon/tip |Updating Fedora|The Fedora 16 software is updated frequently to add features, fix bugs, and upgrade security. Perform a system update to get the latest versions of the packages installed in Fedora: Start the Firefox web browser, turn off popup window blocking (select ''Edit>Preferences'', then select the Content tab and uncheck the box to Block Popups), then login to SeneNET. Open a terminal and type <code>su</code> to start a shell as root. Enter the command <code>yum update</code> This will download and install all of the packages that have been updated since the installation DVD image was created. If you complete this command at Seneca it should run quite fast as Seneca College hosts a Fedora Repository mirror (a copy of all of the current fedora packages, on a local web server).}}
== Investigation 3: What is a runlevel? ==
After the kernel boots, it starts a single program, called <code>init</code>. A running instance of a program is called a '''process''' -- the init process always has a process ID (PID) of 1. All other processes on the system are started by init, or they are started by processes started by init. Most current Linux systems use some variation of the init system originally developed for Unix System V (called "sysvinit") or a newer version called "upstart". These systems employ the concept of "runlevels" -- groups of software that can be selected, so that the system can be run in various modes. In Fedora systems, these runlevels are used: {|class="mediawiki" border="1"!Runlevel!Description|-|0|Halt (powers off the system)|-|1|Single-user maintenance mode, network not running, character-mode display|-|2|''Not normally used - originally meant: Multi-user mode, network not running, character-mode display''|-|Investigation 3|Multi-user mode, network running, character-mode display|-|4|''Not normally used''|-|5|Multi-user mode, network running, graphical user interface|-|6|Reboot|} {{Admon/note|Different runlevel systems|Various Linux distributions may use the runlevel numbers differently. For example, on some Debian/Ubuntu systems, the default (standard) runlevel is 2.}} In order to implement runlevels, init uses a configuration file and a number of script files: * <code>/etc/inittab</code> is the configuration file, which sets the default runlevel.* <code>/etc/rc.d/init.d</code> is a directory of scripts. In order to determine which of the startup scripts should be executed in each runlevel, the one directory per runlevel is created (<code>/etc/rc.d/rc'''X'''.d</code>, where '''X''' is the runlevel). This directory is filled with symbolic links to the startup scripts in <code>/etc/rc.d/init.d</code> # To find out the value of the runlevel your GNU/Linux system goes into after boot, enter the command: <code>grep initdefault /etc/inittab</code># You should get a single line containing ":" as the field delimiter. The second field stores the value of the runlevel the init process will use after a reboot. Record the output in your log book.# A list of processes that should be running at a given runlevel can be found in the directory <code>/etc/rc.d/rc'''X'''.d</code> where '''X''' is the runlevel. Do a directory listing of that directory and study what files are in there. Pay attention to the first three characters of each file name. They have special meaning to the system. Record your observation in your log book.# Make a backup of the file /etc/inittab with the command: <code>cp /etc/inittab /etc/inittab.original</code># Edit the file <code>/etc/inittab</code> and change the default runlevel to 3. Save the change and reboot your system.# After the reboot, you should get a "Text Login Screen". Login with your Learn account and type startx at the command prompt. Describe what happens in your log book.# Enter the command: <code>runlevel</code> -- this shows the previous and current runlevel. Record the values in your book.  Answer the Investigation 4 questions in your lab log book. == Investigation 4: What is the network configuration? ==
# To check the network configuration settings obtained from the DHCP server, run the following commands, describing the output in your log book:
Msaul
Administrators
13,420
edits
Retrieved from "https://wiki.cdot.senecapolytechnic.ca/wiki/Special:MobileDiff/77523"