I'd just like to go on record saying that I vote democrat, but if Hilary somehow steals the nomination from Obama, I will be voting for Ralf Nader or none-of-the-above :(
Wednesday, March 19, 2008
negativity
The conservative movement in this nation never ceases to amaze me. One of the most remarkable speeches of the 21st century was delivered yesterday and it fell upon many deaf ears. What is it about fear that a near majority of people in this country find it so enticing? It is the same fear that allowed popular opinion to sway toward the lies of our fearless president, whose trillion dollar mistake is commemorated today. "The troop surge is working." You have nothing to fear. Except black ministers...
Thursday, February 07, 2008
Invalid Checksums
Apparently, there is a checksum offload engine in my laptop's network card. Unfortunately, this engine doesnt work, at least with the latest Ubuntu release (Gutsy).
The problem manifests itself as a continuous stream of bad UDP checksum errors when monitoring network traffic with Wireshark. In particular, every DNS request my system sent had an invalid checksum error. I did not bother to check for the same problem with other traffic types. In any case, I found a bug report describing this exact issue:
https://bugs.launchpad.net/ubuntu/+source/libpcap/+bug/31273
Apparently it is very easy to turn off the checksum offload feature using this command:
After this modification, my packets are no longer broken!
The problem manifests itself as a continuous stream of bad UDP checksum errors when monitoring network traffic with Wireshark. In particular, every DNS request my system sent had an invalid checksum error. I did not bother to check for the same problem with other traffic types. In any case, I found a bug report describing this exact issue:
https://bugs.launchpad.net/ubuntu/+source/libpcap/+bug/31273
Apparently it is very easy to turn off the checksum offload feature using this command:
sudo ethtool -K eth0 rx off tx off
After this modification, my packets are no longer broken!
Thursday, January 10, 2008
Linux and the HVR 950
Just purchased a Hauppauge WinTV-HVR-950, which is essentially a small USB device that acts as an analog / digital television tuner. Not only can one tune into new digital over-the-air broadcasts, but also HD programming as well. Using a home-made DB2 antenna, I am able to pull in 31 digital channels including 6 HD channels. This was a very pleasant surprise :)
My ultimate goal is to connect this tuner to my PC and the PC to my old HD television so that I can get over-the-air digital channels and rid myself of cable. I attempted to get the tuner working with Ubuntu 7.10 (Gutsy) using this guide ( http://lunapark6.com/usb-hdtv-tuner-stick-for-windows-linux-hauppauge-wintv-hvr-950.html)
This guide ( http://parker1.co.uk/mythtv_ubuntu.php) was also helpful in my attempt to set up MythTV. Unfortunately, I did not succeed in getting the software to work. I may try again at a future date. I was able to get the tuner to work with a few simple command line utilities though. I installed the following packages in Ubuntu:
These utilities allowed me to scan all digital channels identified by the receiver. The scan takes a few minutes, so be patient. Also look at the other example scan files in the dvb-utils directory. Another may be more directly applicable, depending upon your location and interests.
This gives output like the following to a file called channels:
Dont be surprised if you get allot of output on the command line...it complained about every unavailable channel for me. The information above includes the name of the channel, frequency, and encoding. To tell the tuner to tune into a channel, use a command like the following:
Note that we are using 'azap' (for ATSC digital programming). See http://www.linuxtv.org/wiki/index.php/Zap for more information.
Finally, the following command will stream the output of the tuner directly to mplayer for display on the screen:
I have successfully tuned into standard and HD digital broadcasts using this simple technique.
My ultimate goal is to connect this tuner to my PC and the PC to my old HD television so that I can get over-the-air digital channels and rid myself of cable. I attempted to get the tuner working with Ubuntu 7.10 (Gutsy) using this guide ( http://lunapark6.com/usb-hdtv-tuner-stick-for-windows-linux-hauppauge-wintv-hvr-950.html)
This guide ( http://parker1.co.uk/mythtv_ubuntu.php) was also helpful in my attempt to set up MythTV. Unfortunately, I did not succeed in getting the software to work. I may try again at a future date. I was able to get the tuner to work with a few simple command line utilities though. I installed the following packages in Ubuntu:
dvb-utils, dvbsnoop, dvbstream, dvbtune
These utilities allowed me to scan all digital channels identified by the receiver. The scan takes a few minutes, so be patient. Also look at the other example scan files in the dvb-utils directory. Another may be more directly applicable, depending upon your location and interests.
sudo /usr/bin/scan /usr/share/doc/dvb-utils/examples/scan/atsc/us-ATSC-center-frequencies-8VSB > channels
This gives output like the following to a file called channels:
WBFF-HD:665028615:8VSB:49:52:3
Good TV:665028615:8VSB:65:68:4
Dont be surprised if you get allot of output on the command line...it complained about every unavailable channel for me. The information above includes the name of the channel, frequency, and encoding. To tell the tuner to tune into a channel, use a command like the following:
azap -r -c channels "Good TV"
Note that we are using 'azap' (for ATSC digital programming). See http://www.linuxtv.org/wiki/index.php/Zap for more information.
Finally, the following command will stream the output of the tuner directly to mplayer for display on the screen:
mplayer /dev/dvb/adapter0/dvr0 -cache 8192 -framedrop -vo x11
I have successfully tuned into standard and HD digital broadcasts using this simple technique.
Friday, December 14, 2007
Installed Packages
I've been searching for an easy way to itemize all installed packages on a Debian / Ubuntu system, but just found it today. To list all installed packages,
Now, you can use this list to re-install an existing system or duplicate its configuration on a new system:
Finally, run deselect to make the selection changes take effect!
Thank you to Ubuntu Forums for the answer: http://ubuntuforums.org/showthread.php?t=261366
dpkg --get-selections > installed-software
Now, you can use this list to re-install an existing system or duplicate its configuration on a new system:
dpkg --set-selections < installed-software
Finally, run deselect to make the selection changes take effect!
dselect
Thank you to Ubuntu Forums for the answer: http://ubuntuforums.org/showthread.php?t=261366
Monday, December 03, 2007
Finishing my previous thought
After expanding the virtual disk and the partition, simply run resize2fs on the device of interest and the filesystem (EXT2 or EXT3) will be expanded to occupy the full extent of the partition :)
Virtual Disks
Expanding a virtual disk in VMWare is very simple:
Just remember that you still have to expand the partition and the filesystem living on that partition as well. Thanks to http://4sysops.com/archives/expanding-a-virtual-vmware-disk/ for the information!
vmware-vdiskmanager -x 10GB myDisk.vmdk
Just remember that you still have to expand the partition and the filesystem living on that partition as well. Thanks to http://4sysops.com/archives/expanding-a-virtual-vmware-disk/ for the information!
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