Getting Started with Wireless Network Technology

Part III: Adding Wireless to a Linux-Based Laptop or Notebook PC

Mike Angelo -- 28 January 2002 (c) -- Page 2

The boot-time load order for PCMCIA services is set in the /etc/init.d/pcmcia startup-script file. So, you will have to edit that startup script in order to change the load order for the PCMCIA services. If you do not find that pcmcia startup-script file in /etc/init.d/, try looking for it in /etc/rc.d/init.d/ (/etc/rc.d/init.d/pcmcia).

Log on to Linux as a regular user. If you prefer to work in a GUI (graphical user interface) and you are using KDE, then click the K button on the K panel and then System > File Manager (Super User Mode). That gives you Root privileges in that super-user, file-manager window even though you are logged on as a regular user.

If you prefer the command line, open a terminal and su - to Root. (Use the - with su as shown so you will inherit the root user's environment. That way you will avoid those annoying command or file not found error messages, even when you know darn well the command or file is there.)

With your root (super user, or simply su) privileges as gained above, open the /etc/init.d/pcmcia startup-script file in a text editor. If you are using the KDE file-manager, simply alternate (right) click on the file name to bring up a context menu. Then click on Open With > Editors > Advanced Editor.

About six or so lines down in that file you should see:

# chkconfig: 2345 45 96.

(Please see Figure 3.) Change the 45 in # chkconfig: 2345 45 96 from 45 to 09. Now that line should be:

# chkconfig: 2345 09 96.

(The 09 and 45 tell the boot process manager when to execute the pcmcia startup script in the booting sequence. The 2345 tells the boot process to use the pcmcia startup script in run levels 2, 3, 4, and 5.)

Next, you need to force the Linux operating system to re-read that edited pcmcia startup-script file. To do that you need to be at a command line as root. So, if you used the graphical, K-desktop File Manager (Konqueror) to edit the file, now please open a terminal and su - to Root. If you used the command line to edit the pcmcia startup-script file, you already are there.

Then at the root-prompt command-line please type chkconfig pcmcia off and enter it. Next, please type chkconfig pcmcia on and enter it.

Now, if you reboot Linux, the Proxim Skyline 802.11b PC Card should work nicely.

Please keep in mind that Proxim does not support Linux. So if you try to use a Skyline 802.11b PC Card with Linux, you are on your own.

Enabling & Disabling Ethernet Interfaces in Boot Sequence

If you installed Linux with both the wired Ethernet cable plugged into your notebook and the wireless PC Card plugged in, then the Linux boot process will try to start both devices at boot time. That means if you boot Linux with the Ethernet cable removed, there will be a substantial delay while the Linux boot process hunts for the missing wired Ethernet interface connection. You can avoid that delay by disabling the wired Ethernet interface.

If you normally run your laptop or notebook computer with the wireless adapter only, then you might want to remove starting-the-wired-network-adapter from the boot process. Removing it avoids that delay while the boot process tries to find the missing wired-network connection.

To do that you must determine whether your wired, Ethernet-cable interface is Eth 0 or Eth 1 (presuming that you have only two Ethernet interfaces configured.) One way to do that is to disconnect the Ethernet cable from its RJ45 jack on your notebook computer. Then boot or re-boot Linux.

Watch the boot messages. When the boot manager starts to load the Ethernet interfaces, you will see eth0 and eth1 in the boot messages. One of these will indicate OK and the other will indicate Failed. The one that fails is the one that goes with the disconnected wired Ethernet device.

For this example, let's say that eth1 fails. That means that Eth 1 is the Ethernet interface that needs to be disabled.

To disable Eth 1, open up a Super-User Konqueror file-manager window or su- to a root prompt in a terminal window, as you did above when you modified the PCMCIA startup-script. The file to modify is in the /etc/sysconfig/network-scripts directory. You should see several similar files such as ifcfg-eth0 and ifcfg-eth1.

Because eth1 failed during the boot process, the file we want to edit is ifcfg-eth1, which controls the auto-on boot for Eth 1. Please see Figure 4.

In the ifcfg-eth1 file, change:

ONBOOT=yes

to:

ONBOOT=no

Then save and close the ifcfg-eth1 file. Now when you boot Linux on your wireless-networked laptop or notebook, the boot process should skip trying to start the wired Ethernet interface.

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