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Coding The Future Linux Desktop [updated]
the.jedi writes "With the release of GTK+ 2.4, and Gnome 2.6 due out some time next week, it seems of some the Gnome developers are looking at how they'll be coding Gnome and the rest of the Linux desktop. Havoc Pennington of Planet Gnome has written a short blog pondering and analyzing the available options as coders move towards high-level languages like java and C#. He gives a good overview and assessment of technologies like mono, OO.org's UNO framework, as well as other ways of tying new languages to the existing code base. An extremely interesting read for desktop linux hackers everywhere."
Update: 03/17 14:44 GMT by T : Speaking of the future of Gnome, aeneas writes with a list of Gnome 2.6 release parties around the world (linked from gnome.org/start/2.5).
I'm not favoring XUL, but if I read ok, the article mention sthat XUL only has bindings to javascript. These are maybe the best implmented, but ti has also bindings (or being worked on) for perl, python and ruby.
Michel
A big part of the slowness of gtk2 is font rendering. Motif uses (or used?) XDrawString(), so text was done entirely by the server. On the downside, the quality of the text rendering was very poor.
gtk2 draws all text with pango. Pango is a high-quality unicode text renderer with an Xft2 backend. If you have an old X server, this can be pretty slow. If you have a recent XRender extension, it's almost as fast as the old XDrawString().
Owen Taylor did add an optimisation to render text more quickly for text which gtk knows is being drawn over a plain background, this helps old X servers a lot, provided you're not using a pixmap-based theme.
At 8mb on my system (that includes the java class library) that's pretty light. For comparison .NET on Windows weighs in at about 30mb and the Mono RPM (compressed) is about 8mb as well, so it's certainly competitive.
I haven't heard of the Adobes, Macromedias, or Intuits of the world scrambling to rewrite their apps in .NET; what makes HP think that GTKmm or QT isn't good enough? Don't believe the hype dude; the MS marketing machine has been blowing a lot of smoke up a lot of asses.
Yup.
Java/C# are snazzy for:
* Custom application development
* Lightweight distributed and networked systems.
* (Java at least) Cross-platform GUI apps.
* Vertical market software development.
C/C+ are snazzy for:
* Libraries
* Horizontal market applications
Until Microsoft goes out and rewrites MS SQL Server, MSIE, and Microsoft Word in C# (not going to happen, for good reasons), I don't see any reason why there should be any interest in doing the same with the core GNOME apps.
The same goes for Sun and Java. When Sun decides that Java would make a really great language for Open Office and successfully writes an efficient Java-based Office release, then it might be worthwhile considering Java for said use.
Until then, I'd suggest rnning out and actually *using* one of the desktop apps that people have written with Java. Hey...they're slow, RAM-hungry, and annoying to run on systems with different JVMs.
There have been a zillion less efficient languages proposed to replace C (and later C++) over the years. All of them failed to replace C/C++ as a general application programming language. Efficiency matters. The fact that Microsoft is pusshing a high level language and Sun is pushing a high level language (at other people -- notice failure of Wordperfect Java port for an example of why Java/C# are not good choices for horizontal market apps) does not mean that *this* year is the time to move to a high level language. I don't think anyone here wants GNOME or KDE to have a *bigger* RAM footprint, which Java would do.
May we never see th
1) Mozilla and OO are written in C++ not Java or C#
2) Java on a modern hotspot JVM can outperform the equivalent C++ code for stuff that isn't IO limited (ie number crunching stuff)
3) GCJ compiles Java to native code anyway.
I'm not sure I see your point.
We are not hostile at all to DotGNU.
We think we have a better implementation so we keep going forward with that. I don't think we're even competing since DotGNU seems to have different targets than us: for example the reason we built a JIT from the start is because we want Mono to be an efficient developer platform that enables people to move away from unsafe and difficult to use langauges: this of course would be not compatible with an interpreter design which is slow. By all means continue with the DotGNU implementation, improve it and try to build on its strengths, but don't just call us hostile only because we have a different implementation from yours.
Nasty type errors are really rare, though. Normally, you've either done something stupid and the code doesn't run at all (and you have to test everything at least once), or the types are right.
Of course, some languages can be really helpful with their type checking. Haskell often gives some insight into the nature of some code by giving it a more general type. But I find Java tells you nothing you didn't already know.
Python has a few other problems. It's (a) slow even with tools like Psyco.
I've looked at the output of some code from psyco and it looked just like C (provided you stick to C-compatible types, of course). Python tends to off-load critical loops into C libraries (map(), etc). Java tends to be much slower, perhaps because most of its standard library is interpreted?
Modern C++ compilers also have access to profiling information. Moreover, they then can optimize over the true average rather that what happens on the first few times that code is encountered (which may not be that typical).
The Tao of math: The numbers you can count are not the real numbers.
But even so, this information might not be useful.
For example, GCC compiles per file. It doesn't compile the project as a whole, so it can't perform cross-module optimisations.
Another example, how do you efficiently optimise a library statically? Not only that, but the behaviour of the application might depend upon, for example, a read-in piece of text (to determine, for example, if it logged or not). A sophisticated JIT can then generate more optimised code than a C++ compiler over time.
There are loads of cases where a JIT can outperform a static compiler. That's not to say that static compilers don't have a large number of strengths, or can't be modified to overcome a large number of these weaknesses (whole program compilation is already pretty much there for gcj, adding it to the gcc in total might not be that difficult, likewise a runtime profiler could rely on static hints for places that might be good to optimise, akin to dynamo). But at the moment, JITs don't necessarily lose out.
It turns out most S.W.F client code relies too much on poking around "behind the scenes" way of pinvoke badness and the like that there needs to be a real Win32 implementation behind it.
.NET was so they could cast off the shackles of Win32 backwards-compatability, for good and bad reasons both)
(which is also why Microsoft is backing off of S.W.F themselves; the whole point of them going with
That said, mono is in fact working on a S.W.F implementation in conjunction with Wine.
DNA just wants to be free...
Yes, because IceWM and WMaker are written in a unicode-supported toolkit that trades a little bloat for i18n purposes..
Oh wait, they aren't! Metacity is the one that's written to be run anywhere in the world.
Honestly, if there was another GTK+ 2 window manager with all the Gnome hooks built into it to compare it to, then you'd have a platform to stand on.
Otherwise, you may as well be saying 'd00d WTF!!! why is Doom III so much slower than Wolfenstein 3D???? id is t3h sloppy coding!!11!'
I'll try to address some of the issues Havoc presented. Of course, I'm a Mono developer, so I'm biased, but hopefully people can see my arguments are more on the technical side than advocacy.
No rewrites please: this is a very important point: we can't just throw away the current code: we need incremental changes to not disrupt stability and compatibility. I'll just note that using Mono (and C#), interoperability with existing C code is much easier than with Java because of P/Invoke.
Calling managed code from C/C++: Havoc says it's hard, but Mono provides an easy to use interface to do that. Mono is designed to be embedded in existing applications, not just as a runtime for standalone completely managed programs. Also, it would be easy to create a shared library and header files to access managed methods seamlessly: they can be automatically generated thanks to the use of Reflection and the Mono embedding API.
I'm not sure a "simple native component system bridge" would solve the issues, mostly because simple systems are always found later to be incomplete, they get changed and become big, but with all the design warts needed to make a simple design work for not-so-simple constraints.
A minimal Mono system is currently about 2 MB on disk, but no effort yet has been put into reducing it (and I think it's entirely possible, we have been busy implementing features and leaving aside space optimizations). Of course, since the default build of the core assembly has lots of features, much of the reduction in size could be achieved by trimming features that other systems don't have:-). Even without trimming, most people will concour that 2 megabytes of disk space for a shared component is small enough in a desktop setting (and applications compiled to IL code are usually much smaller than comparable C apps anyway).
Community should decide: of course, I agree. Anything that is pushed down our throats by somebody else is not going to work for the free software and open source communities. The solution will need to be choosen because it actually solves issues the developers and the users see. Java had several years to try to attract developers from our community and it had some success in some niche areas (not for desktop applications, though). Mono has just started, but from the comments of the developers that actually used it to write new applications or port existing ones from C, it looks like we are on a good adoption path (even though we didn't release a 1.0 version yet, we are still working on debugging support and documentation is sparse).
Havoc fears the adoption of Mono or Java for the desktop would alienate people and cause forks. I don't think that will happen with Mono, because Gnome will continue to have a diversity of developers who'll prefer using the C libraries directly: Mono allows to keep and interoperate with existing code very easily and we want the migration to happen incrementally, so at first only end-user applications would be written in managed code, while the foundation would still be in C (at least, enough of the foundation to have people happyly writing their own apps in c or with the existing bindings). At that point, when a managed execution environment has proven itself to both developers and users (hopefully) we could start discussing about using it for the foundation, too, if that makes sense. I think Mono is positioned better here to allow this incremental shift of both development and espectations towards a managed runtime.
Problems with a .Net clone: Havoc claims that MS controls the platform
because, even if the core is unencumbered, some assemblies are tied to MS
technologies and there is non standards body or community momentum to build
alternative solutions for a complete platform. Well, considering that until
a couple of months ago there were 5 people developing mono, we have achieved a lot,
not only in the implementation of the runtime, but also, thanks to the large
commun