Fixing Apache Installation after Upgrade to Ubuntu 14.4

October 31, 2014

After an LTS upgrade, my Apache was no longer working. The new version of Apache came with two significant changes to the configuration file.

Virtual Hosts The filter for including hosts from /etc/apache2/sites-enabled had been updated to only match paths ending in the extension .conf. More about it here (see post by augustin from Sep 17).

Permissions outside of normal Document Root The default permissions had become more restrictive disallowing access outside the normal document root. More about it here (see post by Irve from May 22).

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Sensor Swab Type Explanation

July 30, 2013

While looking for a description of the differences in the three types of sensor swab products from Photographic Solutions I came across this reference.

The overall rule seem to be that the key is:

  • Type 1 – For reduced frame (crop 1.3) sensors
  • Type 2 – For reduced frame (crop >1.3) sensors
  • Type 3 – For full-frame (35mm) sensors

There are discrepancies though (e.g. the Nikon D7000 being mapped to type 1).

On a related note Thom Hogan has a nice article on sensor cleaning.

CPU Frequency Scaling under Linux

July 23, 2013

Example for setting the frequency on a dual-core system:
cpufreq-set -c 0 --freq 2000MHz
cpufreq-set -c 1 --freq 2000MHz

Read out current frequency by doing
cat /proc/cpuinfo

ADB Over WiFi

July 23, 2013

This assumes that you have your phone in developer mode, that it is attached to your computer using a USB cable and that it is accessible from the computer through 192.168.0.115.

Switch to wireless ADB by running (on the computer):
adb tcpip 5555
adb connect 192.168.0.115:5555

Switch back to wired by running:
adb usb

Read more here.

Git References

July 2, 2013

To be updated …

Android LogCat

June 12, 2013

The main logging infrastructure on android — LogCat — is essentially a circular buffer (of limited size) stored in /dev/log/main. Debugging tools can sip into it. In order to keep a longer sequence of entries it needs to be connected to adb or a similar system. Apps like alogcat can display the log without having some other computer tethered.

Details are available on this blog.

Resuming a Failed SCP Transfer

May 21, 2013

A failed scp transfer can be resumed using the following command:

 

rsync --partial --progress --rsh=ssh user@host:remote_file local_file

Naturally, you will have to replace user, host, remote_file and local_file.

Hidden Android Developer Settings

May 17, 2013

In Android 4.2 the developer settings have been hidden. Among others, this affects the Nexus 4 phone.

This post explains how to access them.

In short you go to “Settings” -> “About phone” and click the “Build number” item 7 (yes, that’s seven) times.

ADT: The connection to adb is down, and a severe error has occured

May 10, 2013

The Android Developer Tools (ADT) version of Eclipse has a so-called “Android Virtual Device Manager”, available through the “Window” menu. It essentially holds a list of virtual device configurations. A highlighted configuration can be started.

If no configuration is started, running an application will result in the following error message:

[2013-05-10 13:54:45 - MyFirstApp] Android Launch!
[2013-05-10 13:54:45 - MyFirstApp] The connection to adb is down, and a severe error has occured.
[2013-05-10 13:54:45 - MyFirstApp] You must restart adb and Eclipse.
[2013-05-10 13:54:45 - MyFirstApp] Please ensure that adb is correctly located at '/opt/adt-bundle-linux-x86_64-20130219/sdk/platform-tools/adb' and can be executed.

Skype on Debian Testing

April 30, 2013

The instructions on the official wiki worked for me.

Starting a Program at Boot-time

February 9, 2013

First step is to become root. One of the following should do

sudo su
ssh root@localhost

Next step is to copy the skeleton service:

cp /etc/init.d/skeleton /etc/init.d/SERVICENAME

Then update the copy to make sure that the variables DESC, NAME, DAEMON, DAEMON_ARGS, PIDFILE, and SCRIPTNAME are correct:

nano /etc/init.d/SERVICENAME

Then depending on distribution run one of the following (first is for debian, last is for redhat):

update-rc.d SERVICENAME defaults
chkconfig SERVICENAME on

MSP-FET430UIF on Debian Testing

February 7, 2013

Connecting the TI MSP-FET430UIF (a msp430 programmer) to a box running debian testing will not result in a device being created. This is caused by a missing firmware file (ti_3410.fw).

Download it from here (local copy here) and place it in the /lib/firmware directory. Then reconnect the FET430 and the port should show up.

Found the fix here.

Installing Android Developer Tools on Debian Testing

January 11, 2013

Download

Download from here.

Extract

Assuming that (i) /opt exists, (ii) you have permission to write to it, and (iii) you downloaded the amd64 version to ~/Downloads:

cd /opt
unzip ~/Downloads/adt-bundle-linux-x86_64.zip

Verify

Start by running:

cd /opt/adt-bundle-linux/eclipse
./eclipse

Add shortcut to Gnome Shell

Save the following to /usr/share/applications/adt.desktop:

[Desktop Entry]
Version=1.0
Name=Android Developer Tools
GenericName=Android Developer Tools
Comment=Android Developer Tools
Exec=/opt/adt-bundle-linux/eclipse/eclipse
Terminal=false
Icon=/opt/adt-bundle-linux/eclipse/configuration/org.eclipse.osgi/bundles/2/2/.cp/icons/android-64.png
Type=Application
Categories=Programming;
MimeType=text/x-java-source;

Notes:

  1. You must be superuser to write to this location.
  2. There are two references to the installation directory.
  3. There should be a local version of /usr/share/applications/, but I couldn’t find it.
  4. The 64-bit version depends on a 32-bit libncurses package.

At this point ADT should be registered with the gnome activity screen.

Empathy “Network Error” Revisited

December 30, 2012

Empathy should really give better error messages than “Network Error”. The Help->Debug window is not easy to decipher. I still have no idea what is causing it.

This time around I encountered the problem on an up-to-date Debian Testing installation. It affected my Facebook chat. The following command seems to fix it:

killall telepathy-butterfly telepathy-haze mission-control-5 telepathy-logger telepathy-salut telepathy-gabble empathy-chat empathy

 

The Scopists Creed

October 13, 2012

aka the Full Metal Oscilloscope is here.

Inkscape Presentations with Sozi

April 29, 2012

The Sozi extension to Inkscape provides a system for constructing presentations from an SVG file. There’s an introduction.

The approach is to define frames within the SVG and paths between them as translations, zooms and rotations. The resulting file can be viewed and navigated in most decent browsers.

Bootstrap loader synchronization error

February 27, 2012

I am starting to see a lot of tos-bsl errors of the format:

$ tos-bsl --telosb -c /dev/ttyUSB0 -r -e -I -p main.hex
MSP430 Bootstrap Loader Version: 1.39-telos-8
Mass Erase...

An error occoured:
Bootstrap loader synchronization error

According to this post the issue is related to ports not being released properly. Opening and closing the device in a serial console (like cutecom) fixes the problem.

Upgrade to Oneiric breaks VMWare Player

November 28, 2011

After upgrading the Ubuntu install on my laptop from Natty to Oneiric my VMWare Player failed to start. It gave a error about not being able to compile the wmmon module. The compile process reported errors like:

/tmp/vmware-root/modules/vmmon-only/linux/driver.c:783:59: error: ‘SPIN_LOCK_UNLOCKED’ undeclared here (not in a function)

The fix was to repeat the official installation instructions. No need to remove the old one first. This upped the major version number in the progress.

Grouping Facebook Contacts in Empathy

July 16, 2011

You can’t. Facebook doesn’t support editing of groups in their jabber implementation. The trick then becomes to assign groups through facebook.

This is done by logging into facebook and choosing ‘Edit Friends’ from the ‘Account’ drop-down menu. The process is first to create the groups (lists in facebook-lingo) and then to assign contacts (friends in facebook-lingo) to them.

Modifying message of last commit in GIT

July 14, 2011

You wrote the wrong description for the last commit and it annoys you. What to do?

git commit --amend -m "The correct description"

This will modify the history. Further discussion here.

Binary Drivers and Kernel Updates

June 26, 2011

Binary drivers tend to be build against a specific kernel. When the kernel is updated the driver will break if not rebuild. Ubuntu has a mechanism for dealing with this, but it depends on the linux-headers-generic package being installed:

sudo apt-get install linux-headers-generic

Specific drivers may need a few hints to realize that they should rebuild (normally done at boot-time). This page covers the specifics for the proprietary nvidia driver.

Gnome 3 Reference

June 24, 2011

To be updated …

Gnome 3 themes on Natty

June 20, 2011

Installed Natty Narwhal (Ubuntu 11.04) and quickly became annoyed with the new ‘unity’ interface. The old ‘classical gnome’ option worked fine, but I decided to try installing Gnome 3 from PPA.

I ended up with some fallback theme. With some inspiration I managed to fix it using

sudo apt-get remove gnome-accessibility-themes gnome-accessibility-themes-extras
sudo apt-get install gnome-themes-standard

and then choosing the ‘Adwaita’ theme.

List of Graphical Interfaces to GIT

June 1, 2011

Linux

OSX

Windows

Skype via Empathy

February 14, 2011

This thread describes how to do skype chatting in empathy.

The steps to follow – for ubuntu users at least – are:

  1. Install skype: see link.
  2. Install pidgin-skype: sudo apt-get install pidgin-skype
  3. Start skype.
  4. Go to empathy’s account manager and add a bigbrownchunx-skype-dbus account for your skype identity.

Maverick and rpy

December 30, 2010

The version of python-rpy and r-base-core does not match in the current Ubuntu. A workaround is suggested via the relevant ubuntu bug entry: Pull python-rpy from ppa:bigmadwolf/misc instead.

BOINC Control Issues in Maverick

October 27, 2010

A bug in upgraded Ubuntu 10.10 (Maverick Meerkat) installations has caused the boinc manager to lose its menubar. As a result the option to control the execution policy is gone.

The same control is available through the commandline,

boinccmd --set_run_mode always

for starting and

boinccmd --set_run_mode never

for stopping.

DIKU World Community Grid Statistics

October 25, 2010

For statistics regarding the progress of World Community Grid team DIKU, follow this link

Enabling Audio on Macbook Pro and Ubuntu 10.10

October 13, 2010

An update to Maverick Meerkat disabled sound on my laptop (a 13″ mbp7,1). I got it working again by following this guide, which states that:

  1. Add to the end of /etc/modprobe.d/alsa-base.conf the following line:
    options snd-hda-intel model=mbp55
    The file can be opened by running: gksudo gedit /etc/modprobe.d/alsa-base.conf
  2. Save the file and reboot the computer

Regaining Lost Touchpad Preferences on Ubuntu 10.10

October 12, 2010

After updating to Ubuntu 10.10 – the Maverick Meerkat – I discovered, that I had lost the touchpad preferences on my Macbook Pro 13″ (mbp7,1). A quick-google revealed this post, describing the solution:

  1. Install the driver: sudo apt-get install xserver-xorg-input-synaptics
  2. Log out and then back in
  3. Open System>Preferences>Mouse and go to the Touchpad tab