Making the ViewSonic Tablet PC Run Linux
A few more items needed to be addressed before this tablet really was usable for the ISP. The first issue was the PCMCIA wireless LAN card. As it is a fairly popular PCMCIA device, I expected it could be plugged into a running system and be detected. Reality turned out not to be quite that easy. When I plugged the card in, no messages appeared in /var/log/messages and it was not seen by the system. Perhaps a setting could be tweaked somewhere, but I thought I first would try having the card inserted into the machine for a warm-reboot. That seemed to work just fine. Incidentally, the system correctly would handle ejecting the card, but not its reinsertion. But as long as it was present at boot, there were no problems with it.
Mutual Data Service's software requests were quite simple. All they really needed (so far) were Ethereal, the graphical network traffic analyzer; kismet, an 802.11 wireless network traffic sniffer; and xmms, the extensible media player. Xmms and Ethereal were installed with the basic install, and kismet was installed from DVD by using YaST.
The last task is making it quick and simple to change network profiles, a task that SuSE makes easy. The System Configuration Profile Management (SCPM) module, accessed through YaST, allows the system administrator to change the network location of the system with a few mouse clicks.
To use SCPM you first need to start YaST, which requires the root password. Select Profile Manager from the System group to open a new window for SCPM (Figure 5). SCPM is not enabled when it first is installed. Figure 6 shows our final configuration, in which you can see the General Setup section and the Options... button. Selecting the Options... button brings up the SCPM options window (Figure 7). SCPM can be activated by selecting the Enabled button near the top of the screen and then the OK button in the lower right.
Figure 5. A Window for SCPM
Figure 6. Final Configuration
Figure 7. SCPM Options Window
To use SCPM, you must configure the network settings and then save them into a profile. New profiles can be created simply by changing settings and storing them in that profile.
This is the process I used to create our set of profiles:
1. Open the YaST SCPM module on one desktop and the YaST Network cards configuration window on another (Figure 8).
Figure 8. Windows for YaST SCPM and Network Cards
2. Select the Add button on the SCPM screen to open the dialog for creating a new profile (Figure 9). Make the profile from the current system configuration and check the make the new configuration active box. Select the OK button.
Figure 9. Creating a New Profile
3. The Special profile settings screen should appear (Figure 10), where you can enter a name for the new profile and a short description. This screen also allows specifying pre- and post-start and stop scripts, which provide amazing flexibility when changing profiles. I was doing basic network settings changes, so these scripts are not needed.
Figure 10. Special Profile Settings
4. Going back to the YaST Network cards configuration screen, I made the changes I wanted in this profile. In this case, I disabled the RJ-45 network connection and configured the SMC wlan0 device. Select Finish on network changes to close that window. I now have the system configured the way I want the current profile to be stored, but the profile is not yet stored.
5. Now go back to the main SCPM page and Add a new profile. (It might seem like a step is missing here, but it is not.) When the new profile dialog comes up, it can be created either from the current system configuration or from another profile. If created from the current system configuration, do not make it the active profile. Select the OK button, enter a name and description for the new profile and commit the changes.
6. Back at the main SCPM window, select the newly created profile and click the Switch to... button. The changes to the network configuration made in step 4 are be seen by SCPM as modified from the current profile (not the one created in step 5), so I was asked if I wanted to save those changes to the current profile before unloading it (Figure 11). The default is to save the changes (note the X next to the network resource group), so I chose OK and the changes were saved to the current profile, the affected subsystems were stopped (networking in our case), the new profile from step 5 was made active/current and the stopped subsystems were restarted.
Figure 11. Saving the Current Profile
7. The system now has the newly created profile active. I now needed to go back to step 4 and make changes to the current profile before creating another new one and saving the current.
As an added ease-of-use feature, I set root's KDE environment to have two desktops, one for SCPM and one for everything else. As long as YaST is running on the SCPM desktop when root logs out, YaST automatically starts up and goes to the correct desktop at the next login.