splashutils-1.1.9.3 released

I’ve just released splashutils-1.1.9.3, hopefully the most stable version of the 1.1.9.x series :) It includes the usual amount of bugfixes, some enhancements (among which is better compile-time configurability; the ebuilds don’t take advantage of it yet, sorry) and some new features (font stuff — font styles, text positioning, variables evaluation, etc).

This is also the first 1.1.9.x release that has a full, up-to-date documentation. The previous versions lacked some descriptions of the new features. If you want to design a cool new theme which will use some of them, now might be a good time to start the work :)

Speaking of documentation, I’ve also written a new document describing the splash initscripts used in Gentoo. This was requested by several people maintaining support for splashutils in other distros, but I guess Gentoo users might find the new doc interesting as well, should they ever want to learn how the pretty boot-time stuff works on the inside.

If you want to help with testing, please do echo ">=media-gfx/splashutils-1.0" >> /etc/portage/package.unmask and re-merge splashutils. Suggestions and bug reports are appreciated.

The splash and breaking initscripts

Yesterday I spent a good few hours on chasing a bug related to the new splashutils. For quite some time my qmail and svscan have been misbehaving on my system. svscan seemed to start properly, but when I logged in, the process was dead and had to be manually restarted. After that everything worked fine. It turns out this kind of problems is caused by adding CONSOLE=/dev/tty1 to the kernel command line. So far I have discovered two services which cause trouble — hddtemp and svscan. I’ve opened bugs for both of them (#86550, #86562) and added info about the issue to the gensplash troubleshooting section on my devsite. Hopefully this will save others from the trouble I had with fixing this problem.

Changes in splashutils

As you might have noticed, some two weeks ago I released a new version of splashutils (1.1.9), which introduces many new features and some rather large changes in the way the splash works.

There have been a few factors that pushed me towards this release. First of all, people seem to like it when stuff is moved from the kernel into the userspace. Thus, starting with fbsplash-0.9.2, what little silent mode code there was in the kernel, has been removed. The truth is, the silent mode can easily be handled by userspace, with no help from the kernel. The verbose mode on the other hand can’t be moved to the userspace, unless one is willing to write a complete userspace console. That’s why fbsplash is there to stay, at least for some time. The silent image is now displayed on its own tty. This allows the user to switch back and forth between verbose and silent mode. It also automatically solves problems with consolefont, provided it doesn’t touch the silent tty.

Second thing that made me realize that some changes are necessary is a simple test I have performed. Try doing for ((i=0;i<65535;i=$i+1000)) do splash_util -c paint -m s -t livecd-2005.0 --progress=$i ; done. It’s slow! A lot slower than I suspected it would be. It turns out that loading and unpacking the background picture every time it is to be repainted isn’t such a good idea, even if the whole process is repeated only a few times during boot. Fortunately, a solution has existed long before the problem was discovered. It’s called the ’splash daemon’ and was originally planned for gensplash. The splash daemon code has now been integrated into splashutils. The new mode of operation allows us to avoid the constant reloading and unpacking that was taking place with previous versions of splashutils.

The third reason for introducing the changes was a feeling that gensplash is moving far too slow. I started the project more than half a year ago and since then there hasn’t been a single release. Sure, there is some progress as far as the code is concerned but it’s still nowhere near a final version. Taking splashutils as a base, I was able to implement many of the features planned for gensplash in just a few days. At least now it will be possible to test them and see them in action.

I realize most of these new features is undocumented yet, and thus hard to take advantage of, but this will be taken care of soon. I plan to include full documentation in the next release of splashutils.

Physics workshop

During the last week (Mar, 14th-18th) I took part in a physics workshop organized by the Polish Children’s Fund (don’t let the name fool you!) as part of its “educational enrichment and support programme”. The workshop took place at the Institute of Theoretical Physics of the Warsaw University.

There were three people in my working group (Marcin Bieda, Marcin Grzybowski and myself) in which we were working on “simulating the effects of large masses within the framework of general relativity” under the guidance of Mikołaj Korzyński.

For me, the workshop was a lot of fun and a source of new knowledge and experiences. The result of our 5-day work is a program that can simulate the optical effects in the vicinity of a massive, sperically symmetric and non-rotating body (we’re using the Schwarzchild metric). At this point, the code needs some clean-ups and possibly some new features as well (support for relativistic aberration and gravitational redshift, rendering directly to a X window, generating animations, etc). As soon as the cleanups are complete, I’ll publish the code in a new science-related section of my devsite. I’ve been planning on creating such a section for quite some time and I guess this program, along with a bunch of other ones, will be a good way of starting it.

The workshop has been my first chance to use general relativity in a practical project. I have been interested in the topic for quite some time before, but I never really got into applying it to anything. Now that I have a program to play with, I hope exploring this subject will be easier and more fun.

I’m currently reading “A First Course in General Relativity” (Bernard F. Schutz), “Gravitation” (Kip S. Thorne, et al) and I’m waiting to get my hands on “Relativistic Astrophysics” (Marek Demiański). If you happen to know any other good textbooks on general relativity, I would be grateful for sharing information about them with me.