Photographing high buildings gives you a picture where the left and right sides converge toward the top, making it look like the building is topling over backwards any moment.

Before digital photography, the only way to fix this were shift lenses. With digital images, you can fix the distortion, but that used to be a partly manual process.

Enter ShiftN. With the click of one button, it looks for lines which should be vertical, and modifies the picture to look like it was taken with a shift lens. Here is an example picture I took of the Bibliothèque Nationale in Paris. Left is the original, right the version ShiftN came up with.

ShiftN is freeware. It is written for MS Windows, but runs perfectly on Linux, thanks to Wine.

And although the ShiftN Web site is in German, the program's UI comes with English texts.

Despite its name, POPFile can sort mails using a couple of protocols, including IMAP. It monitors a configurable list of IMAP folders (usually your inbox), classifies the mails with a Bayesian algorithm, and moves them to one of the target IMAP folders. If the classification was wrong, just move the mail to the correct folder in your email client, and POPFile will learn from its mistakes.

POPFile has been sorting my mail into four folders named 00todo, 01important, 02later and 03trash for the last week. It now has an accuracy of 78%, and is especially good at getting rid of mailing list threads which I am not interested in.

Installation instructions for Linux, Mac OS X and MS Windows can be found on the QuickStart page. While the IMAP module is labelled as experimental, I did not have any problems with it so far. Contrary to the ImapInstructions, it comes with the standard installation of version 0.22.4. So skip the first part of the page, and start with the "How to get it running" section.

Update 15 Jun 2007: See Dell Latitude D800 Suspend to RAM with Fedora 7 for an updated version of this article.

Suspend to RAM on my Dell Latitude D800 just works with Fedora Core 5 and the free nv driver. Suspend also works with the binary-only nvidia driver, but the display either stays black or shows some fascinating color patterns after resume.

It turns out that fixing this is easy, and well worth it. The nvidia driver not only gives you 3D support, but also feels faster when switching tabs in Firefox.

The following has been tested with kernel-2.6.17-1.2174_FC5 and NVIDIA-Linux-x86-1.0-8774 on a Dell Latitude D800 with a GeForce FX Go5200.

As described in the nV News Forum, the following has to be done:

1. Append "agp=off" to the kernel line in /etc/grub.conf. This disables the built-in AGP driver and allows nvidia to load its own.

   kernel /vmlinuz-2.6.17-1.2174_FC5 ro root=/dev/vg1/root quiet agp=off

2. Edit /etc/X11/xorg.conf and set the NvAGP option:

   Section "Device"
       ...
       Driver         "nvidia"
       Option         "NvAGP" "1"
   EndSection
   	

3. Edit /etc/pm/functions-nvidia and disable the "vbetool post" call:

   resume_video()
   {
   	...
   #       /usr/sbin/vbetool post
           ...
   }
   	

4. Reboot, log in and check if the nvidia AGP driver is used:

   # cat /proc/driver/nvidia/agp/status
   Status:          Enabled
   Driver:          NVIDIA
   	

Suspend and resume should work now.