Archive for September, 2009

Photo trap for Bats

September 19, 2009

Came across an article describing one guys efforts in photographing bats slurping water from a pond while in flight. The pictures are strangely beautiful.


Cloning a VirtualBox Virtual Machine

September 12, 2009

Locating clear guidelines describing the proces of creating a copy of an already existing machine (also known as cloning it) is not an easy task. I gave up when I came across an unofficial guide or two.

In VirtualBox, virtual machine definitions are stored separately from disk images. Cloning the machine can be reduced to the matter of cloning the disk(s) and creating a new machine which uses the cloned disk(s). Since disk images contain a unique identifier (UUID) a simple copy – as performed by the operating system – won’t do. Instead, use the following command:

vboxmanage clonevdi ORIGINAL_IMAGE NEW_IMAGE

The default locating for disk images is ~/.VirtualBox/HardDisks and the files use the .vdi extension.


$ vboxmanage clonevdi ~/.VirtualBox/HardDisks/Disk.vdi ~/.VirtualBox/HardDisks/DiskClone.vdi
VirtualBox Command Line Management Interface Version 2.1.4_OSE
(C) 2005-2009 Sun Microsystems, Inc.
All rights reserved.

Clone hard disk created in format 'VDI'. UUID: cd4972c2-b57f-4b59-90f3-db151ac131e5

Then create a new virtual machine which uses the DiskClone.vdi image.

Adapting a Leica R-mount lens to Nikon F cameras

September 12, 2009

This site sells kits to convert Leica R-Mount lenses to Nikon F mount.

Features (according to site):

  • The procedure is fully reversible.
  • The lens will focus to infinity.
  • Nikon cameras will show focus confirmation light in viewfinder.

It seems like a few Hong Kong based brands are offering alternatives on ebay. Don’t know if they are trustworthy though …

leitax also has kits for other exotic lens/body combinations. Just about any combination of:

  • Lens: Contax Carl Zeiss, Leica R
  • Body: Canon EOS, Minolta/Sony alpha, Nikon F, Pentax, Sigma

9/11, 1973 edition

September 11, 2009

Chilean coup d’état

Leica announces M9, X1

September 9, 2009

After a long line of rumors Leica today announced the M9 digital rangefinder camera along with the ‘beginners’ X1. An artful Leica M9 brochure was leaked.

DPReview has a preview of the M9, a brief preview of the X1 and a tour of the Leica Solms Factory. Luminous Landscape also has an article on the X1.

Gizmodo has a well-written article on the event and the phenomenon that is Leica. A quote about the press event:

“I’ll say—I’ve never gotten so many looks of pity for carrying a Sony DSLR as I did at the press event today. No one looked down on me; they just looked … sad.”

The announcement was – for some reason – done as a webcast:

Evolution unable to generate folder list

September 6, 2009

After a system freeze, evolution ceased to be able to generate the folder list for my inbox. The statusbar said Error While Generating message list. Clicking on the message popped up this dialog:

Error dialog

According to this bug report the issue might be linked to evolutions use of SQLite.

In the same bug report it was suggested that the following command might solve the issue.

cd ~/.evolution/mail ; for i in `find . -name folders.db`; do echo "Rebuilding Table $i"; sqlite3 $i "pragma integrity_check;"; done

I didn’t have sqlite3 installed, so I ran sudo apt-get install sqlite3 first. For me this command located a handful of files called folders.db and sqlite3 did find errors in one of them: ~/.evolution/mail/local/folders.db.

To make sure that I had the right file I ran

sqlite3 ~/.evolution/mail/local/folders.db "pragma integrity_check;"

which again presented the errors. In the bug report someone explained that missing folder.db files would be regenerated, so I tried stopping all evolution-related processes (evolution-data-server and evolution-alarm-notify will linger after exitting the main program) and removed the file. I then started evolution and everything came up nicely.

On the inability to create evolution filters after migration

September 5, 2009

I recently moved my evolution setup from one machine to another, in the proces changing my username. Mostly the move was successful, but signatures got cleared and the ability to add filters broke. This post describes a workaround for the latter issue.

First a working evolution setup was backed up (File->Backup Settings …) and restored (File->Restore Backup …) on a different computer as a different user.

After adding a message filter and applying it (Message -> Apply Filters) a warning would pop up (‘asjo’ was my username on the first machine):

Filtering Error


Make sure no processes related to evolution are running. Then edit the ~/.evolution/mail/filters.xml file:

  1. Locate the rule in question (enclosed by <rule></rule> tags). It is most likely in the buttom of the file.
  2. Inside it, you will find a <folder/> tag (Assuming your filter is a move-to-folder operation). Mine says <folder uri="email://5/Inbox/tinyos"/>.
  3. Replace the 5 with local@local so that you come up with something similar to <folder uri="email://local@local/Inbox/tinyos"/>.

Then save the file.

In order to test the change, simply start up evolution and try to apply filters as before.

Windows must-haves

September 3, 2009

While fooling around with Windows (XP variant) I found a few missing essentials:

  • For transferring files there is putty (there’s an installer common to almost everything)
  • For calculating checksums (MD5/SHA1) there is HashTab which adds a tab to the file properties dialog box

I intend to update this list as I find additions.

Radeon Mobility 7500 under Jaunty

September 2, 2009

Update 2: On a clean install of Karmic Beta, this was fixed out of the box.

Update: The config below results in some stability issues on my machine. It might be isolated and it might not be. But for me it triggers random restarts once a day or so and a reproducible restart when I try to run

cvs -z3 co -P tinyos-2.x

which really doesn’t make sense. I have reverted to this xorg.conf (which is slow) and hope for the best in Karmic …

Original post:

Since the arrival of Jaunty Jackelope (Ubuntu 9.04) my laptop has performed miserably on the 2D side of things. It’s an IBM ThinkPad T42 2379-R4U. Thats an ATI Radeon Mobility 7500 with 32MB and a 1400×1050 screen.

Today I found this page and as a result my /etc/X11/xorg.conf now contains this device section:

Section "Device"
Identifier "Configured Video Device"
Option "AGPMode" "4"
Option "AGPFastWrite" "True"
Option "EnablePageFlip" "True"
Option "AGPMode" "4"
Option "AGPSize" "64"
Option "RingSize" "8"
Option "BufferSize" "2"
Option "EnableDepthMoves" "true"
Option "RenderAccel" "true"
# Eyecandy Stuff
Option "AccelMethod" "XAA"
Option "EnablePageFlip" "true
Option "DDCMode"
Option "SubPixelOrder" "NONE"
Option "ColorTiling" "false"
Option "MigrationHeuristic" "greedy"

This gives me decent, but not great, performance.