Resolution issues in LTSP

Yesterday I brought my whole class down to my newly configured LTSP lab with my dual quad core xeon, 8 gigs of RAM server powering my 22 Pentium 3, 128 MB RAM thin clients across a 10/100 switch with gigabit uplink from the server to the switch. From everything I've read this setup should work fine, especially since I've got firefox running as a local app now. Alas, it was not long before the familiar old complaints were ravaging my ears. "Mine's frozen!" "The computer's not working!" "Mine's slow!"

Ugh.

I did my best to alleviate the immediate issue by moving kids off of computers and that seemed to help a bit, but I still think there must be some sort of issue with my switch or something. I'm not entirely sure what the problem could be, but I knew that 128MB was pretty lean for the clients so after school I collected all the old PC133 SDRAM I had in stock and installed an extra stick in each client. This brings me to 256MB RAM in each machine which should be adequate.

I figured out how to check on the switch settings and all the ports are running at full duplex, but I've got a parent here who's pretty saavy with network issues so I might have him probe around a bit more.

One thing still left me puzzled yesterday, and that was the fact that some of the machines were not showing the screen correctly. Things were showing tracks around the screen and the resolution was different on different monitors. This despite the clients all being the same make and model. Very confusing.

It's taken me a couple of hours this afternoon, but I finally figured out the problem. I noticed that the problem was only happening on certain monitors, Dell M782 models to be exact. The Dell 781P's, which are actually a year older than the 782's, were working perfectly.

After wading through the ltsp handbook for a while and trying all kinds of settings in my lts.conf (/var/lib/tftpboot/ltsp/i386/lts.conf) I finally found the one setting that fixed all my problems:

XRANDR_DISABLE = True


Apparently Xrandr was trying to autoconfigure the settings on the monitor and was somehow getting them wrong. By disabling xrandr I was able to dictate the resolution I wanted and all the tracing and slow performance disappeared! Sweet. Here's my complete lts.conf if you're curious, but disabling xrandr was really the key to getting the monitor resolutions right. Cheers! -joe

[Default]
LDM_DIRECTX = True
XRANDR_DISABLE = True
X_RAMPERC = 80
X_MODE_0 = 1280x1024
LOCAL_APPS = True
LOCAL_APPS_MENU = True
LOCAL_APPS_MENU_ITEMS = firefox
SEARCH_DOMAIN = 192.168.0.1 || Change this for your own network
DNS_SERVER = 92.168.0.1 || Change this for your own network
RCFILE_01 = /etc/init.d/chmod-resolv.sh

Xrandr, why Xorg crashed last time and the benefits of Internet based computing.

Well my reinstall of Gutsy went well. I figured out that Xorg crashed last time because I had changed the display driver from the experimental Intel driver to the older i810 driver. While this had been suggested in one of the forums as a way to enable a secondary monitor output it apparently was also the reason Xorg could not find any screens the next time I started the computer up. Since the reinstall I've tried using the same terminal command that worked for me before:

xrandr --output VGA --auto

and it seemed to do the trick. I was also able to then shut down the computer and start it again later without a hitch, so that's always a good thing.

I suppose if I were a bit more knowledgeable, daring, or motivated after the crash I could have figured out how to reconfigure Xorg so that I didn't have to do a complete reinstall of edubuntu, but after a few minutes of contemplating this I realized that there really wasn't anything on the machine that I didn't also have somewhere else. Moving from using Word to Google Docs hasn't always been easy, but in cases such as this it was enormously advantageous. I suppose I do have to worry about Google's servers crashing and losing all my stuff, but those guys seem to know what they're doing over there so I think I'll take my chances. I'll try to blog more about our school's recent move to Google Apps, but for now I'm pretty focused on the wedding. We're like 52 hours away at this point and I'm not even packed for Jamaica yet. Cheers! -joe

Xorg is ruining my life!

It would be hard to state how much I was looking forward to the Ggaphic user interface for multiple monitors that was supposed to arrive with Gutsy. Since the beginning of the school year I've had a pretty nice VAIO laptop that used to be my principal's machine (she got a new macbook), but I've been unable to use it at all with a projector to show slideshows and the like to the staff during presentations or meetings. Perhaps designing and implementing a reliable GUI for external monitors and projectors is more difficult than I understand, but this is a such HUGE issue for so many people that I'm honestly appalled that it hasn't been addressed sooner.

In any case, all is to be fixed with Gutsy right? I mean I'd seen screenshots of the Multiple Monitors GUI since the beta releases. How great would it be to be able to just connect a VGA projector to my laptop and mirror the output? I mean, under Windows MCE the machine does it AUTOMATICALLY! I just plug in the cable with the projector on and BAM! it's up on the screen. It should honestly be this easy under Ubuntu too. Alas it is not.

I wrote last time about my disappointment with the Multiple Monitors GUI on my classroom computer, but today has been an absolute debacle. Not only did the GUI not work (surprise, surprise) but after doing some command line junk (which again, should NEVER be necessary) and actually getting the setup to work fine, my Xorg server crashed and as I type this, Edubuntu is reloading all over again. Crap.

So I'm sure there's a very good reason the GUI doesn't work. I've actually read about it on the forums and whatnot, something to do with specific video cards or something. Here's the thing though: I Don't Care. This is something that "just needs to work". It's unacceptable that something this necessary requires me to scour forums, sort through a bunch of stuff about changing device drivers, xrandr, my Xorg.conf file and then eventually leads me to try some command line code that appears to work but also crashes my system.

The good news is that bulletproofX is coming with Hardy Heron and is supposed to solve these problems the way windows did way back in the last millennium, namely by defaulting to a basic GUI display set instead of just crapping out entirely. So if you thought I was anxious for this change before Gutsy, you can imagine how I'm feeling right now. Hoping beyond all hope. -joe