Category Archives: Linux

Semantic Mainstream

Databases, Linux, SemWeb

I spent most of my wednesday at the Copenhagen Bella Center at the anual Linux Conference : Linux on Enterprise 2006. It was organized in part by OSL — thanks to Magenta for the invitation.

It was quite interesting to hear about practical experiences with open standards and open source in the government, and listening to Peter Quinn of Massachusetts fame was inspiring (as was the free beer — the presentation included hilarious jabs at Richard Stallman).

Most interesting was the fact that the IDC analyst as well as the special guest Dirk van Rooy from the EU Information Society/IST activity, both mentioned intelligence in computing as “the future”, with clear references to the Semantic Web (and the omnipresent intelligent refrigerator).

Another point: The May/June issue of Oracle Magazine contains an article on the Semantic Web, with sidebars tooting the horn of Oracle 10g Release 2: Semantic Breakthrough

I think it seems like this stuff is going to stick…

Linksys WPC54G and Redhat Linux

Linux

Just in case someone else runs into the same problems I did — and in case I need it later — here’s what I did when trying to get my laptop with Redhat Linux 9 and a Linksys WPC54G wireless card working together.

First I tried the Linuxant drivers, but luckily they didn’t work — they aren’t free (as in beer). Then I went on to try the NdisWrapper NDIS API implementation, and even though I had to build the tools and modules myself because of a kernel version mismatch, they ended up working perfectly without too much hassle.

To build the tools and install the XP driver (NdisWrapper works by emulating the NDIS API for the non-free Windows drivers):

make install
ndiswrapper -i WPC54G/lsbcmnds.inf

Next up is creating an interface configuration file in /etc/sysconfig/network-scripts/ifcfg-wlan0:

MODE=Managed
ESSID=wifi.mfd-consult.dk
KEY=<26 hex characters for the 128 bit WEP key specific to my AP>
DEVICE=wlan0
ONBOOT=yes
BOOTPROTO=dhcp
USERCTL=no
PEERDNS=no
TYPE=Wireless

Then came the tricky part: The WPC54G is a PCMCIA card, but on my Redhat Linux 9 installation, the networking is set to start up before the PCMCIA interface is initialized. To overcome this problem, I changed the chkconfig parameters for three of the startup scripts (the NFS script failed to work properly if not started after the network):

  • pcmcia: 21 96
  • network: 22 90
  • nfslock: 23 86

After that, I issued the following commands to reset the sequence:

chkconfig pcmcia reset
chkconfig network reset
chkconfig nfslock reset

The only thing missing was to make sure the PCMCIA and NdisWrapper drivers were loaded on startup, by simulating a card insert event — if necessary — and forcing the drivers to load:

rmmod ndiswrapper 2>/dev/null
cardctl status | grep "no card" > /dev/null && cardctl insert
modprobe ndiswrapper

That’s it, running /etc/init.d/network restart should bring up the wireless interface, after which I could turn off the ethernet connection by setting ONBOOT=no in /etc/sysconfig/network-scripts/ifcfg-eth0.