Error:
end_request: I/O error, dev sr0, sector 537392
If you’re getting a similar error filling your screen once you’ve installed Ubuntu, don’t panic. It’s pretty common which is basically because Ubuntu (or any other Linux distro) can’t control your CD/DVD drive properly, it’s probably trying to open/close it but doesn’t know if it has or not. The problem is that you don’t get to see what Ubuntu wrote before because it’s filled your screen up with this error.
If you’ve just installed Ubuntu this probably happened when it wanted you to take the disc out and close the cd tray (if there is one) then hit Enter to finish the installation, so just do that and ignore this error.
When trying to install Gnome Planner ( http://live.gnome.org/Planner ) in Arch Linux, I came across this error:
Error:
/usr/bin/pygobject-codegen-2.0: line 11: /usr/bin/python2: No such file or directory
make[2]: *** [planner.c] Error 127
make[2]: Leaving directory `/home/alex/Desktop/planner-0.14.4/python'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/alex/Desktop/planner-0.14.4'
make: *** [all] Error 2
To fix this, I made a symbolic link from /usr/bin/python2.7 to /usr/bin/python2, this should work with other similar errors involving missing python2 file.
sudo ln -s /usr/bin/python2.7 /usr/bin/python2
Once you have made the made the symbolic link continue to make and install the program as usual.
If you’re running off a live USB disk or changing your graphics card the error below might appear when Xorg is looking for the wrong drivers or device. You might also get this error while using the Nvidia drivers, I found however this was caused by some of the extra options added into the xorg.conf file (usually located /etc/X11/xorg.conf). If the case is that it’s a problem with the aditional options I suggest making a backup of the file and attempting to comment out (#) aditional options, this will need a bit more of an expert eye to see what isn’t needed though.. You can also use the following to rollback to a working version when using the Nvidia drivers.
There is a pretty simple fix, if it is caused by broken or changed xorg.conf file:
Fix:
Make a backup of your current Xorg.conf, just in case something goes even more wrong and it can be easily restored:
sudo cp /etc/X11/xorg.conf /etc/X11/xorg.bckup
Now you’ll want to restore the failsafe (sometimes called xorg.conf.backup) config to be used as the default:
sudo cp /etc/X11/xorg.conf.failsafe /etc/X11/xorg.conf
Yeah, it was that simple (if this error was caused by a broken or changed xorg.conf anyway. So you can continue and start the x server with:
startx
Error:
X.Org X Server 1.9.0
Release Date: 2010-08-20
X Protocol Version 11, Revision 0
Build Operating System: Linux 2.6.24-27-server i686 Ubuntu
Current Operating System: Linux ubuntu 2.6.35-22-generic #33-Ubuntu SMP Sun Sep 19 20:34:50 UTC 2010 i686
Kernel command line: noprompt cdrom-detect/try-usb=true persistent file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash -- maybe-ubiquity
Build Date: 16 September 2010 05:39:22PM
xorg-server 2:1.9.0-0ubuntu7 (For technical support please see http://www.ubuntu.com/support)
Current version of pixman: 0.18.4
Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Fri Mar 4 11:35:54 2011
(==) Using config file: "/etc/X11/xorg.conf"
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
(EE) No devices detected.
Fatal server error:
no screens found
Please consult the The X.Org Foundation support
at http://wiki.x.org
for help.
Please also check the log file at "/var/log/Xorg.0.log" for additional information.
ddxSigGiveUp: Closing log
giving up.
xinit: No such file or directory (errno 2): unable to connect to X server
xinit: No such process (errno 3): Server error.
Numeric
Error:
Traceback (most recent call last):
File "", line 1, in
ImportError: No module named Numeric
Package:
sudo apt-get install python-numeric
ImageTk
Error:
ITraceback (most recent call last):
File "", line 1, in
ImportError: No module named ImageTk
Package:
sudo apt-get install python-imaging-tk
Previously I was having problems with Ubuntu dropping wifi connections and failing to reconnect, to solve this I wrote a script which would kill the network-manager and then connect using iwconfig commands (here). While this works fine, it felt a little hacky, having to have a script running as sudo constantly in the background checking for a dropped connection. After a little searching I came across cron (the time based job scheduler ) and /etc/rc.local (a script which is run after all other initialization scripts have ran, allowing for scripts to be ran on startup) so from this I decided to split the old script up into connection and checking scripts which could be ran from init.d/local and cron, respectively.
Firstly my startup script in /etc/init.d/local which sets up and connects to the wireless network, open the file as sudo:
sudo gedit /etc/rc.local
Paste in the following:
#! /bin/sh
service network-manager stop && service networking stop
iwconfig wlan0 essid NETWORKNAME
iwconfig wlan0 key WEPKEY
ifconfig wlan0 up
dhclient3 wlan0
sleep 10
if iwconfig wlan0 | grep -o "Access Point: Not-Associated"
then
ifconfig wlan0 down
sleep 10
ifconfig wlan0 up
fi
exit 0
Next the script for checking the network is still connected, if not attempt to reconnect (named wirelesscheck.sh):
#!/bin/bash
if iwconfig wlan0 | grep -o "Access Point: Not-Associated"
then
ifconfig wlan0 down
sleep 10
ifconfig wlan0 up
fi
Make sure this script is executable (from the directory of the script):
chmod +x wirelesscheck.sh
Note: This is setup in the sudo crontab, only because this command needs root privileges – other commands could be added to a user crontab (by removing sudo from the following.)
Now, edit (-e) the crontab for sudo:
sudo crontab -e
If crontab has not previously been used choose an editor (I used nano – 2) and append this line to the bottom of the file and change the frequency and directory of the script. The current settings will run it every 5 minutes (*/5) every hour, day, month and year and the file is located in “/path/to/script/wirelesscheck.sh”.
*/5 * * * * /path/to/script/wirelesscheck.sh
If you have any issues, leave a comment and I will help if I can.
[swscaler @ 0xbf2130]No accelerated colorspace conversion found from yuv420p to bgr24.
This problem is basically an issue converting YUV to RGB using ffmpeg, in order for it to work ffmpeg needs to be recompiled with x264. To get around it use the following to recompile ffmpeg and OpenCV 2.1/2.2:
- Follow steps 1-to-4 of FakeOutdoorsman’s guide on ubuntuforums.org – here
- OpenCV 2.1/2.2 Install Guide by Sebastian Montabone - here
If you’re getting this error but you’re still connected to the internet this page might help. This error is sometimes caused by repository’s which are down or broken.
Failed to download repository information
Check your Internet connection.
From terminal run the following command:
sudo apt-get update
If the output runs through a few repositorys but ends with something similar to the below (most probably with different repositorys failing) and ultimately stopping your updating process then there is a good chance you can fix it by just removing those failing sources from the software sources.
Err http://ppa.launchpad.net maverick/main Sources
404 Not Found
Err http://ppa.launchpad.net maverick/main amd64 Packages
404 Not Found
W: Failed to fetch http://ppa.launchpad.net/bugs-sehe/gparted/ubuntu/dists/maverick/main/source/Sources.gz 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/bugs-sehe/gparted/ubuntu/dists/maverick/main/binary-amd64/Packages.gz 404 Not Found
E: Some index files failed to download, they have been ignored, or old ones used instead.
Software Sources can be found under either:
Applications > Ubuntu Software Centre > Edit > Software Sources..
OR
System > Administrator > Synaptic Package Manager > Settings > Repositorys
Click the Other Software tab.
Nnow find the repositories which caused the failure on the update and uncheck them and then close the Software Centre.
Re-run the update command and hopefully everything will work!
sudo apt-get update
Check the example below where gparted was causing the error:
Having gone through several upgrades and countless repository’s added to the software sources, things can begin to get really messy really quickly and often begin to screw up when updating the system if you’re not careful. You may find yourself, like I have, wanting to restore your sources.list file back to its default in order to get things working again.
In order to do this there is a pretty handy webapp available called the “Ubuntu Sources List Generator” - http://repogen.simplylinux.ch/
By moving through each section it enables you to select your country, release and then check each repository you want to add, not only does it support all the official ones for things like security and updates, it also allows for 3rd party repos such as Banshee, Chromium, Conky and VLC amongst a bunch others. Once you have what you want hit generate and it’ll create a nice, comment, new sources.list file ready for you to replace your old one with.
You may want to backup your old sources.list just in case with the following command:
sudo cp /etc/apt/sources.list /etc/apt/sources.list.bkup
Once you have that you can open the sources.list and simply paste the new one in from the repogen:
sudo gedit /etc/apt/sources.list
Paste, Save and Close the file and now you should paste the generated GPG keys, found just below the generated sources.list file, into your terminal.
Everything should be back to default and allow you to once again update everything.
(cd ./brain/psom && make)
make[1]: Entering directory `/home/ubuntu/pyrobot/brain/psom'
(cd csom_src && make _csom.so)
make[2]: Entering directory `/home/ubuntu/pyrobot/brain/psom/csom_src'
gcc -c -g -I -I/usr/include/python2.6 som_pak_wrap.c -I/usr/include/python2.6 -Isom_pak-dev
som_pak_wrap.c:125: fatal error: Python.h: No such file or directory
compilation terminated.
make[2]: *** [som_pak_wrap.o] Error 1
make[2]: Leaving directory `/home/ubuntu/pyrobot/brain/psom/csom_src'
make[1]: *** [csom_src/_csom.so] Error 2
make[1]: Leaving directory `/home/ubuntu/pyrobot/brain/psom'
make: *** [brain/psom] Error 2
To fix
sudo apt-get install python2.6-dev
I have an updated fix for this issue using a startup script to connect and a time scheduled script for checking the connection, rather than having one constantly running in the background, avalible here – http://alexsleat.co.uk/2011/01/09/a-more-elegant-solution-to-ubuntu-wi-fi-reconnecting-issue/
I’ve been having some trouble with my wifi on Ubuntu recently but I think it’s because I’m almost out of range of the access point. The problem is that once it disconnects it never seems to be able to reconnect unless wireless is disabled and re-enabled. No doubt there is another way of fixing this issue but it gives me a chance to write my first shell script.
In short the script disables network-manager (it was trying to do things auto which was screwing with things), sets up the connection and connects then checks for a string in the wireless card parameters which will only occur if it’s disconnected, if the string appears it’ll disable and re-enable the wireless device which seems to allow it to connect again. If it’s connected it’ll wait 3 minutes (180 seconds) before checking again where as if it does disconnect it’ll check again 30 seconds after it’s tired rebooting the device.
Here’s the script, be sure to try it if you’re having the same problem (you might need to change the wireless device ‘wlan1′ to yours) and comment if I’m doing something wrong or there’s another way around this, cheers.
#!/bin/bash
service network-manager stop
iwconfig wlan1 essid NETWORKNAME
iwconfig wlan1 key NETWORKKEY
ifconfig wlan1 up
dhclient3 wlan1
while true;
do
if (iwconfig wlan1) | grep -o "Access Point: Not-Associated"
then
ifconfig wlan1 down
echo "not connected, rebooting Wifi"
ifconfig wlan1 up
sleep 30
else
echo "connected"
sleep 180
fi
done
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About Hi, my name is Alex. I just got through studying Robotics at UWE and I am continuing to do a MSc by Research also in Robotics.
I enjoy a whole heap of things but on this website I mostly post linux, programming, machine vision and other similar topics.
You're free to redistribute anything you find on here, unless it states otherwise, as long as you are not selling it for profit and you link back to my site. Cheers.
Disclaimer Just to cover my ass.
Any information on this site is for informational purposes only, I take no responsibility for the accuracy, reliability, bla, bla or bla to it. Any information you use, you are using at your own risk. I am in no way liable for any loss, damage of data, hardware or anything else in connection with the use of this website.
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