Friday, January 26, 2007

ethne with X

Well, I cannot determine the problem with kappa, though I don't think it is just static electricity. It's getting harder and harder to get it to boot, so I'm going to put it away for now and try to get working later. I went ahead and installed X on ethne, though I'm really feeling the drop from Fedora Core 6 to CentOS 4.4. CentOS is wonderful for servers, but I'm going to need a number of things that aren't available for RHEL yet. I'm using Xfce 4.2 (yikes!) because RHEL is still at GTK+ 2.4.x... OpenOffice is still at version 1... etc. So things are kind of old here. I'm probably going to try to install FC6 later next week to get things up to speed, though I'll need to borrow a CD burner from someone...

In the meantime, I need to write my sermon for Sunday :)

Wednesday, January 24, 2007

Laptop troubles

Today after I finished about five hours of work, kappa (my laptop) froze. Thankfully my work was screen'd away on ethne (my server here at Moody) so I wasn't too concerned about losing all that work - I could just reboot and reattach the screen session. Rebooting... that turned out to be a bigger issue than I planned.

Kappa has had some trouble recently coming out of hibernation - the light would come on but nothing would appear on the screen and I'd have to hard shut-down. I thought it was just a Windows problem, but it is a warning sign of deeper problems under the hood. Tonight, kappa was freezing up continually in Windows and I was having trouble even booting the machine. It looked like a bad RAM problem, as I couldn't even get the BIOS to show up, but I tried switching out both DIMMs (I have two 512s) and no noticeable results. Thankfully the problem is still intermittent and I was finally able to boot to Fedora.

One of the reasons I prefer Linux is that it actually tells you what's going on in your computer. When the freezes happened in Windows, there was no error message at all to give me a clue. When I first booted Fedora, there was an error about my ipw2200 firmware and then an error "psmouse.c: bad data from KBC - timeout bad parity". That must be it. On every subsequent keypress, the this psmouse.c error would appear on the commandline.

To Google we must go. About 300 hits for this error message, and one of the most informative is on the Linux kernel bugzilla. Several people have had this message and were probably referred here. They have common symptoms - laptops with intermittent freezes in both Windows and Linux. A few people debate whether it is a hardware or software problem, but I'm sure the intermittent nature of the problem and the fact that it exists in both Windows and Linux points to a hardware issue. One post in the bug report caught my attention: the idea that it is the result of an ESD - Electrostatic Discharge. Maybe this is it! I have definitely felt more static around me recently. That, combined with the particular clothes I'm normally wearing here in Chicago (my new coat, my scarf) may have contributed to the problem.

I'll let you know how things turn out. In the meantime I'm going to make sure to back up my school folders to ethne. If Kappa dies completely I can always install X on ethne and use it as a desktop in a pinch. "There are levels of survival we are prepared to accept."

Tuesday, January 23, 2007

Brilliance Bordering on Irrationality

I don't really get Dr. McDuffee, though one thing is certain: he is unlike any teacher I have ever had. I don't think all the things I'd heard about him could have prepared me for his class, either. Though he and Dr. Litfin teach two halves of the same course, Christianity and Western Culture, they could not be more opposite in their teaching styles. Dr. Litfin could occasionally wax poetical at times, but overall his teaching style was straightforward, fact-oriented, linear, and concrete. Dr. McDuffee, on the other hand, thrives on rhetoric. Everything is interconnected with everything. I'm still trying to get a handle on how to learn from him, and his class has made me realize what a linear thinker I am. Dr. Litfin was easy for me to follow; Dr. McDuffee is not. However, I've met other people in the class who tell me that their experience is the opposite; Litfin was hard, and McDuffee makes more sense to them.

I've been thinking about this a lot, particularly since the class is still new to me. I think I'm finally beginning to understand that Dr. McDuffee's primary objective in class is not to transfer the course material into our brains; rather, it is to get us to think. This is his goal. CWC is merely a context. I suppose all of Moody is merely a context. Maybe I can learn more from him than I originally thought.

Another issue that this has brought to my mind is the issue of learning styles. If I am a linear thinker, I may have the propensity to leave the part of my audience behind - the part that more readily understands Dr. McDuffee's lectures than Dr. Litfins. I can't be all things to all people, but it did get me thinking: who do I isolate when I say such and such?

When I'm out of Moody, which of these teachers will I remember?


Xfce 4.4.0 final was released Sunday. I installed it on kappa (my laptop) yesterday and it went smoothly. I've been following the development of this project with some interest over the past year, so I've been testing out each development release and I've learned a lot about managing a project. I like Xfce's minimalist philosophy and the "snappiness" feeling of the environment. Thunar is a neat file manager that has plenty of convenient options like mouse gestures. Windows explorer even feels slower than Thunar. Speaking of which...

Over the past few months, my Windows XP Home install on kappa has been getting slower and slower lately. Boot time is getting longer and longer, and loading apps takes much more time. I have no idea what the problem is, as my Fedora Core 6 install has not slowed down at all. I'm planning on wiping the whole drive and reinstalling both OSes, but that will have to wait till I'm home again. Maybe Fedora Core 7 will be out by then :) single sign-on

For a while we've talked about implementing a single sign-on for the services on Here are some notes I jotted down about how to do this.

  • Mediawiki
  • phpBB
  • mailinglist?
The user logs in to a customized form. Upon proper authentication with the LDAP database, the web application sets the login cookie(s?) for the various services. Clicking "Logout" on any one of the services logs the user out of all services.

Possible complications:
  • Mediawiki uses user id numbers as well as usernames. phpBB may do this as well.
  • phpBB (or others) may also need to set session ids in a database - potentially a problem if this expires based on user activity - can we remove this?
  • Mediawiki's database structure for user profile options is a minor headache
  • Where does the mailinglist store user information?

Possible implementations:
  • Create an application to set the proper cookies for each service (more complicated; not a very elegant solution)
  • Hack the existing services to handle a single "logged on" cookie. (more elegant, but potentially less secure. If there is a security flaw in our implementation this might render other services vulnerable. Also if there is any future upstream security vulnerabilities in one service it might affect other services.)
  • Note: Either of these will require carefully analyzing the implementations of the authentication mechanisms for each service. If we need to upgrade a service, we will have to carefully track what changes are made so that they can be "patched" into future versions. (Example: Let's say that we install version X of Mediawiki. If version X is later found to have a cross-site scripting vulnerability, we will need to upgrade to version Y, but we also need to make sure our customizations fit into version Y.)

To what degree should the individual services' profile databases be merged into the LDAP database? One of the cool parts of this will be the ability to sync email address changes, etc. but is this going to be viable with every service, everywhere? Will we need to create a "single profile editor" in addition to the single-sign on? It'd be cool, just more work :) Basically we need to decide whether the LDAP will handle authentication only (just username/password) or an email address, or even other profile information.

Things to store in LDAP
  • Username
  • Password

Possible things to store in LDAP:
  • Email (confirmed?)
  • Group membership for each service (Admin, Moderator, etc.)
  • phpBB variables (id number?, signature, avatar, website, etc)
  • mediawiki variables (watchlist, etc.)
  • mailinglist variables (subscriptions, active/inactive, digest, etc.)

I don't have much experience with LDAP; in fact I've only briefly played around with PHP's LDAP functions. I guess I'll learn more if this project ever gets off the ground :)


My name is Ken Dreyer, and currently I'm a sophomore at Moody Bible Institute in Chicago, IL. I live in Northern Virginia and intern for a US Government agency. I plan to use this blog to post what's going on in my life, etc. Hope you enjoy reading :)