Yesterday I stumbled upon KDE Plasma, which is an attempt to bring some innovation into KDE's next major release.
So they discovered that desktops, except for minor incremental fixes, have hardly improved over several decades. This is a good start.
Sadly, it mostly already stops here. It seems they made the discovery, but have no idea what to do about it. Reading their "Vision" document, it is much like reading Microsoft announcing a new Windows version: Everything will be so much better, and more buzzword-compliant, and new possibilites, and stuff... But going down to the details, you realize that hardly anything has really changed.
OK, that is a bit unfair. There is a bit more in Plasma beyond the realization that change is necessary. There is for example some rough notion (in the form of extenders), that the desktop geometry needs to become more dynamic -- though they constrain it to a specific domin, instead of making it a more fundamental concept. There is also a rough notion of alternative sessions for different use situations -- though they create a specific solution for desktop layout, instead of considering a more fundamental concept. Yes, there are some things going in the right directin, even if in extremly small steps.
And there is this applet concept. It isn't really new; similar concepts existed in specific environments for a long time. It isn't even terribly new as applied to the desktop. Beginnings existed in the form of dockapps and similar for quite long; and Apple, though not very long, has something -- I believe -- quite similar to what they are planning in Plasma.
Nevertheless, this made me consider the topic a bit closer. So, what are the distinctive concepts that make up these applets?
Basically, we have comparatively small, independantly developed hacks, adding functionality to the application/system, without touching the core. There are numerous examples of such an approach resulting in a thriving community of extension developers: TeX/LaTeX, Emacs, Perl, Firefox and Greasemonkey come to mind.
The most fundamental property is probably the fact that those hacks -- whether called extensions, widgets, applets, whatever -- do not touch the application/system core, but are developed using some extension language/API. There is a number of implications from this: People can start writing improvements without knowing the language of the core (usually more low-level than the extension language), or the core code -- just build on some simple APIs. People can do their improvements independantly, without discussing with the core developers, according to an own release schedule etc. They can distribute them independantly. Problems are less critical, because they do not touch the core, and because they affect only those people who explicitely chose to use the extension. For the same reason obscure features can be implemented without bloating the core. And so on. While some of the advantages may be actually organisational or even psychological rather than technical, all of them contribute to lowering entry barriers for people to contribute improvements, for getting actively involved.
The good news is: The Hurd lends itself to such a concept. With a hurdish application infrastructure constructed of small components building upon each other, the whole system actually could be considered the applet idea taken to extreme. (Which is one possible explanation why I like it...) All services being exported via filesystem interfaces, we also always have very accessible extension APIs to easily plug applets into. And with the concept being consequently implemented throughout the system, it's much more powerful than any solution limited to the topmost layer like in Plasma or any other specific approaches possible on traditional systems.
Now the only thing we really need to be careful about, is to ensure Hurd components are really easy to create, distribute, and install...