Drools and Maven
I spent the day playing with Drools, mostly with an eye for porting the RDFS rules into it. After fiddling with JARs for ages I decided that I should just let it go, and use CVS. That meant I needed to build the system, and that meant I needed Maven.

I'd never heard of Maven before, but it seems to be an XML based build system non unlike Ant (yes, I can see that it's a little different, but in Drools it's being used to do the builds). The main page describes it as a "project management and project comprehension tool".

So I ran the examples through Maven, and these worked fine. But to integrate Drools we need to set up the environment without Maven, and it wasn't as easy as I thought. I took all of the JARs I thought I needed from Drools and put them in the classpath. Then I ran the example... only to find that it didn't seem to be configured correctly. The stack trace didn't help much, but there was an error message which seemed to indicate a problem either in configuration or the ability to find to namespaces:

no semantic module for namespace 'http://drools.org/rules' (rule)

The Maven XML configuration did not appear to offer any hints on configuration, so that left the possibility of a missing class. I added a few, and then all the JARs provided with Drools, and none of it helped. I thought to try running Maven in verbose mode, but -v didn't seem to do anything. Finally AN suggested I try maven --help which said that -X provides a debug option. Some days I end up feeling really dumb.

Debug on Maven showed a whole heap of classes under a ~/.maven/repository directory. Huh? Where did this come from? Well Maven seemed to have a LOT of JAR files which Drools didn't come with, but obviously needed, including some directory-service-type JARs. This got it going, and has let me proceed with writing my own code that doesn't use Maven. Took me long enough. Hope I'm more productive tomorrow.

LG DVD Burner
I got the drive replaced, but I haven't been too happy about how the new drive has behaved. This time it's a 8042B, rather than an 8041B.

The first thing I did was format a DVD-RAM disc. This worked perfectly (whew!). Then I tried to burn a DVD-R. This failed, but unlike the returned drive it told me instantly that it wouldn't burn the disc. The old drive would take several minutes before failing, so this seemed to be an improvement.

Back to Windows, and I tried to burn a DVD-RW disc with verification. The burn proceeded, but it took a couple tries before the drive acknowledged the disc. Once the burn finished, the verification didn't even start. This had me concerned about the ability to read the disc, so I tried opening it in Explorer. This too failed, but I thought to look at the properties of the drive, and found the "Burn" options. Changing some of the settings in there gave me a message stating that enabling the drive for reading would mean I would be disabling the ability to read and write DVD-RAM. This looked really promising. Sure enough, I could suddenly read the disc. So I tried a new burn with verification. This started well, but halfway through verification it stopped. No error, but it didn't proceed for over an hour.

I'm wondering about the fact that Windows can't configure the drive for both DVD-RAM and DVD-R at the same time. If this is a drive setting, then this would explain what I saw when I couldn't write to DVD-R after formatting a DVD-RAM. I've rebooted to Linux, and I'll have a go at dvdrecord again later.

So within the space of a couple of days I've become really dissatisfied with LG drives in general. I'll probably start using it more as just a DVD-RAM, and let the new notebook (when it gets here) meet all my DVD-R needs. Then I can replace the LG with a better name drive that does dual layer once I get a little money together. These drives are getting really cheap lately. The LG I bought originally cost $230, and now it's down to $120. The dual layer version is only $190 (and no, it's more than just a firmware difference). Matsushitas, Sonys and the like all cost more, but I'm pleased to see prices coming down so rapidly.

I'll just have to research if another manufacturer supports all formats (+/-/RAM).