Category Archives: Linux

Kernel 2.6.30 is a Go

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I initially thought this would be a rather uninteresting release, especially when we learned Xen dom0 didn’t make the cut. Following the changelog line-by-line, this one still didn’t seem very interesting to me. But analyzing the sum of parts, I have to consider 2.6.30 a ‘golden’ kernel — certainly the best in a while.

There is solid improvement top to bottom here.  A lot of the new KMS/DRM stuff from Fedora 11 has worked its way up stream.  File system work is too much to mention, but highlights include relatime, writeback by default for Extfs, NILFS2, Btrfs development and more. FSCache works as advertised.  Also some groundwork for NFS 4.1, which will eventually bring us pNFS.

Boot speed seems fast as ever, but I haven’t taken the time to do any empirical analysis.  Your results here will be hardware dependent but async initialization of certain subsystems is a welcome move in the right direction.

Basically, a solid release with a good balance of new stuff but mainly refinement of existing systems and merging of longstanding patches.

Kernel Newbies has, as usual, a great change summary: http://kernelnewbies.org/Linux_2_6_30

Kernel developers don’t get Xen

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The recent bruhaha surrounding Xen on LKML (http://lkml.org/lkml/2009/6/2/475) is really disheartening.  Essentially, the Linux kernel devs are at a disconnect with users.  Some are proposing narrow-minded ideas such as DROPPING software paravirt or merging Xen as a whole into the kernel.

I use Xen for a few primary reasons:  it bar none has the best speed — full software paravirtualization pays dividends here;  it is mature;  it works on perfectly good machines that don’t happen to have the latest chips;  it does hardware passthrough on these same systems;  it has great live migration that actually works.

Ingo Molnar wants you to send all your perfectly good enterprise iron to the landfill even though these systems will last 10+ useful years without boneheaded software decisions such as this.

These same FUDsters want to strip the crossplatform nature of Xen dom0 out too.  Xen dom0 runs on NetBSD and Solaris.  It is a true hypervisor and will plug into exisiting architectures, and not force you to use Linux for everything.

I have to admire all the hoops Jeremy Fitzhardinge has jumped through to date, as I know my patience is wearing thin.

Xen powers huge sites such as Amazon and services like linode.com/slicehost.com.  By not having dom0 in the kernel where distros such as Ubuntu and Fedora can easily integrate it, kernel devs are doing a disservice to users.

I use KVM, VMWare, and Virtual Box at work in addition, but Xen is firmly entrenched in my toolbox.  The roadmap they have looks great, and I just don’t see a reason for decline in Xen popularity.  High availability in Xen 4.0 is what I’ve always been waiting for.

Jeremy has gone to great lengths to work with upstream but keeps getting shot down and asked to do something else when he meets one requirement.  The solution is to merge Jeremy’s conservative dom0 patch set and work on a technical solution to the patches that the FUDsters consider bad.  It’s what the users want!

El Reg Humor and Java in free software

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The Register has a good article on Sphinx search with some entertaining pop-shots at Java and “enterprise software” that got a rise out of me:

Solr is popular with the enterprise crowd, who love its Java. Being a Java program, Solr includes no shortage of technology whose acronyms contain the letters J and X.

This tickles the enterprise pink, because these sorts of developers love nothing more than hanging out around a whiteboard drawing boxes and arrows and, from time to time, writing XML to make it look like they’re doing real work. Solr thrives in this environment, being an Apache Foundation project, the Apache Foundation, of course, widely known as a cruel experiment to see what happens when bureaucrats do open source.

Having a bit of experience with Java from academia and a few open source projects I make use of, I can’t help but laugh at how comically and concisely the editor summed it up.

By and large, successful open source projects tend to be written in languages other than Java. The entire GNU/Linux OS stack is primarily C, with some components using C++ like KDE, OpenOffice and Firefox.  On the ever popular web front, PHP, Ruby, and Python lead the pack.

I think it turned out this way for a multitude of reasons.  When working on the OS stack, the power and control of C and C++ are hard to beat.  The plethora of libraries and raw speed of these compiled languages set the bar high for any newcomers.  Java exists as a kludge, mildly useful for desktop apps and mildly useful for web apps while historically having a lot of problems.  Native look and feel have long been the layman’s complaint, though SWT has done a pretty good job there.  Of course, omnipresent Java in the Linux world is relatively new.  I think Java would have been the darling language of client apps had it been open sourced sooner, but this came about 7 years too late to have a large impact on shaping the common FOSS userland.

It is interesting how the open source projects built with Java tend to be highly bureaucratic and abstract.  I think the bottom line is that FOSS programmers do what they do because it is fun and demand pragmatism.  The “enterprise software” attitude/baggage that many Java apps and libraries carry are a big turn off to pragmatism and the hacking culture.  The barrier to entry for Java web programming is also much higher than its “scripting language” competitors, which carry light and simple frameworks that focus on results, not procedure.

Java itself isn’t that of a bad language.  I actually enjoy working with it in school (…though I think it really isn’t appropriate as an introductory teaching language, shielding important concepts from students.  Maybe a future post?..).  When it comes time for real work though, I consider Python, C,  C++ more pragmatic depending on the job at hand.  That, and the fact that most of the common scripting languages are gaining JIT compilers may accelerate Java toward status as a legacy language.

Your thoughts?

To users that miss xorg.conf and complain about it

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I get requests from users and see questions all the time for “where did my xorg.conf go in the latest Ubuntu or Fedora?”, though it is usually a bit more of a flame.

The quick answer… press Ctrl+Alt+F2 or similar to log into a TTY console, or type ‘init 3′ into a root X terminal.

If you haven’t already, log in as root and  kill X or type ‘init 3′ if you want to be heavy handed.  Then run:

X -configure
mv ~/xorg.conf.new /etc/X11/xorg.conf

xorg.config in two commands.  Run the ‘init 5′ command to get back to your GUI login (or kdm or gdm or startx, etc if you know what you are doing.  Worst case remove the .conf and restart.)

If you are advanced enough to edit an xorg.conf, the above should be a cakewalk and you shouldn’t complain about it.

Regardless, you should investigate ‘xrandr’ which makes it simple to do runtime adjustments.

If you are a newbie, look into a gui.  KDE has KRandRTray which makes controlling outputs and resolutions a breeze.  Don’t forget to toggle the output on with the Fn key if you are a laptop user.

Needless to say, Xorg is moving in the right direction.  Stop complaining about it.

FS-Cache merged in Kernel 2.6.30

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FS-Cache has been merged into the upcoming kernel 2.6.30.  This allows for a generic caching interface in the kernel for other file systems.  For example, you can use local hard disks to cache data accessed via NFS, AFS, or CD-Rom.  Since these tend to be high-latency while the disks are low latency, it should provide for a nice speedup.

Of particular interest to me, I contacted maintainer David Howells who is a Redhat employee.  I asked whether this infrastructure would help with large disk image files stored on NFS — a common though not particularly efficient case for VMWare, Xen, KVM, etc.  His exact response was “Quite feasible.  As long as you have a local disk on which to cache the files.”

I am quite happy as I run this setup at work for some production VMs since it allows for easy migration and backup without the complexity and cost of a SAN or cluster FS.  I look forward to testing when 2.6.30 hits the stable tree.

Good Linux File System Developments

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ext4 has sparked good controversy on the LKML. Aside from the recent delayed alloc and fsync issues, the whole FS stack is getting some much needed attention.  Indeed, Linux file systems are starting to feel like first class citizens again with ext4 and Btrfs (merged in 2.6.29 for testing!) and the surrounding infrastructure being worked on.  A lot of long overdue problems are being mitigated.  Jens Axboe claims 8% single drive and 25% array speedup with some recent pdflush patches.  This is very good news for all users since disk I/O has had a fast growing gap with CPU and main memory bandwidth, even with SSDs.  The fruits of this labor are quite visible with recent boot speedups in distros like the upcoming Fedora 11.

Mandatory reading:

Arora, a refreshing new Qt/WebKit browser

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The Gentoo Qt maintainers have been doing a fantastic job of getting cutting edge Qt software into shape with the qting-edge overlay.  I’ve been running Qt 4.5 since beta1 and am pleased with the direction it is going.  Recently the devs bumped the Arora ebuild to version 0.5.  Arora is a lightweight browser based on Qt and WebKit.

I must say, I am impressed.  This browser is lightning fast.  The interface is pleasing, yet minimalist.  You get all the benefits of recent WebKit, and the nice cross-platform nature of Qt.  It feels much faster than Konqueror4.2, and the recent WebKit engine means better compatibility.

It works with all the sites I’ve thrown at it so far and performs great on the Acid 3 test.

Arora 0.5 Acid3 Test - 100/100

Arora 0.5 Acid3 Test - 100/100

All in all it reminds me of Firefox’s early days.  Very mean and lean.  Firefox 3.1 beta2 has served me pretty well, so I don’t think I’ll abandon it yet, but WebKit browsers are becoming quite compelling.

The WebKit devs are also pushing some interesting new ideas out with CSS animation.  This example gives Flash-esque falling leaves.  Maybe we will see less reliance on Flash in the future with the new video/audio tags and work such as this.  It would be nice to move presentation back into structured [X]HTML and CSS, which is portable, easier to parse, and light weight.

Leaves CSS Animation

Leaves CSS Animation

If you are on Gentoo, bump to Qt 4.5rc1 and take a look easily (both are in portage):

emerge -av arora

I’ve seen it hit Fedora Rawhide recently as well.

Only one problem: icon is a bit conspicuous  :-P

Arora Icon

I hate Ubuntu

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I hate Ubuntu.  I immediately lose respect for anyone who runs it, and especially those who advocate it.   Here’s why:

Name 20 features, release-for-release or year-for-year that have not come from Redhat.  Redhat basically runs the show when it comes to Linux.  This includes things like NetworkManager, Gnome, Xorg, GCC, glibc, LVM, KVM, kernel, file systems et al.  Redhat has developers making significant contributions to the entire FOSS software stack upstream.

Ubuntu on the other hand pulls most of the heavy weight packaging from Debian with each release.  They then perform minor patching and testing.  It generally lags behind Fedora by a release or two in parts of the software stack.  I never see @ubuntu or @cannocial email addresses in upstream changelogs.

So tell me again, how exactly does Ubuntu innovate?  They even struggle to release a new theme with each release, and artwork is about the only original thing in Ubuntu.

Yes, Ubuntu is stable because they are standing on the shoulders of giants.  Most of the hard work is hashed out before they ever import software into their repositories.  This is fine, and what FOSS is all about, but I prefer to be in with the leaders rather than the followers.

What really irks me and what has really brewed my hatred are Ubuntu users.  They seem to think Ubuntu is responsible for all that is good in the FOSS world.  I have just proven how false this is.  In my experience, Ubuntu support mechanisms (IRC, mailing lists, forums) are much less helpful than the alternative.

If you want a nice desktop distro, run Fedora or OpenSUSE.  If you like control, run Gentoo.  If you need stability, run RHEL/CentOS or Debian.  But please, don’t feed the idiot magnet that is Ubuntu!

Good open source journalism

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I have to hand it to the guys at The H Open (formally Heise Online Open Source Edition).  They have excellent coverage of the latest happenings in FOSS software.  They also have great coverage of software releases and break it down to the important new bits.  Finally, it is not overburdened with legal BS or thoughtless benchmarks like many other Linux news sites.

In short, the content is very relevant and professional.  It is worth picking up their RSS feed.

One Small Step for QT, One Giant Leap for Free Software

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QT Software, under the graces of Nokia, has released the superb QT cross-platform toolkit under the LGPL.

This. is. HUGE.

For the libre software purist, this still benefits you, if indirectly.  Companies that make changes to the toolkit must still submit patches.  More influential, GPL incompatible software may now readily use QT for free.  This will likely foster more QT centric developers, boost adoption of the underlying stack (Linux, etc), and lower the barrier for vendors to release cross-platform tools.

From a Nokia business perspective, it makes perfect sense and makes the whole thing that much more beautiful.  “QT Everywhere” is really a possibility now.  And, it’s beneficial to Nokia as well as the ecosystem they are enriching.  The more QT developers, the bigger the talent pool for Nokia software.  The more contributors, the better the toolkit.  Win.  A small company like Trolltech could not afford to do this, but to a big dog like Nokia, the revenue from commercial licensing is insignificant and unimportant compared to device sales.

I know the company I work for, Analog Rails, will be able to take advantage of the license switch.  Being previous commercial QT customers, it was expensive to juggle around machines to maintain compliance.  For a companies like VMWare that deploy cross-platform software and maintain their own cross-platform extensions, this surely must be compelling.  I say, the more the merrier!

What a great day for free software, computing, and life in general :-) .

Ars Technica has outstanding coverage of the news: http://arstechnica.com/news.ars/post/20090114-nokia-qt-lgpl-switch-huge-win-for-cross-platform-development.html