This article was originally written in 2011, and was slightly updated in 2014.

Filesystem types and (lack of) compatibility

Despite the fact that we’re no longer living in the 1980s, filesystem-compatibility between operating systems seems to remain an issue in computer-land. The filesystem basically defines the way in which files are organised on a disk. In the 1980s, the popularity of MS-DOS led to widespread adoption of the FAT filesystem, which was also used in earlier Windows versions (½/3/95/98/ME). As NT-based Windows versions (NT/2000/XP/Vista/7) started becoming the mainstream consumer-versions, more and more computers started using Microsoft’s proprietary NTFS.

Nowadays, most external USB harddisks are sold pre-formatted with an NTFS-filesystem, while camera flash-cards and USB thumb-drives tend to still use a FAT32 filesystem. NTFS …

For a couple of years there have been a number of great open-source programs around for encoding video, both in Windows and (Ubuntu) Linux. Some of them provide a nice graphical user interface, but the best ones are still commandline tools, such as ffmpeg and MEncoder. They are extremely flexible, but unfortunately also have a bewildering number of commandline options. This page lists a few invocations I regularly use.

Extracting DVD titles

To extract a single title from a DVD, first copy the DVD to harddisk:

dvdbackup -M

Next, use totem or vlc (under Plackback->Title) to find out the number of the title you want. For our example we’ll assume that the DVD files are in a directory called DVD_VOLUME/ and that we want the second title. Finally, copy the title …

For some reason, repairing broken equipment is one of these tasks that I tend to put off for months, if not years, because it feels like it’s going to be a lot of hassle.

About a year ago the volume knob broke off my Kenwood KRF-V5090D audio video surround receiver during transport. For a while I was able to make it work again by gluing the parts back together, using a matchstick and some polyurethane resin. In the end, this didn’t hold though, and it became increasingly difficult to set the volume. Given that I bought the thing quite cheaply in a second-hand store and the remote control was missing, I decided to try and replace the volume knob myself. The amplifier is a member of the Kenwood KRF-V and VR …

This post was originally written in 2012, and was slightly updated in 2017.

When I first started writing stochastic, individual-based computer simulations in 2005, I thought it would be a pretty straightforward job. Although I’m technically a biologist, I already had quite some (self-taught) experience in C-programming and knew about Object Orient programming. Also, my history of hand-optimising assembly code for the Atari Falcon had taught me a thing or two about writing fast code. Or so I thought. Of course I then proceeded to walk into just about every trap that a naive non-professional software developer can walk into… Here are some of the things I learned over the past years, quite a few of these by trial and error…

Debugging

It is often said that a software developer spends 50 …

Repairing a damaged PDF-file

Ghostscript can “repair” some damaged or buggy PDF-files, by regenerating them. Try something like:

ps2pdf damaged.pdf fixed.pdf

Believe it or not but ps2pdf will happily accept PDF as input, and from it create a new PDF… You can use all the usual Ghostscript options. If you don’t specify any, default values will be used to generate the output PDF. But for instance, if you’re generating a high-quality PDF for printing, try:

ps2pdf -dPDFSETTINGS=/prepress damaged.pdf fixed.pdf

This is needed to fix PDF files generated by OpenOffice.org 3.2.1, which have invalid xref entries (bug #615812). These PDF files can be viewed in Ubuntu and MacOS X, but cannot be printed in the Windows version of Adobe Reader.

Alternatively, you can use …