Crisis of Capitalism

Animated presentation held by sociologist David Harvey and Professor Philip Zimbardo for Royal Society for the encouragement of Arts, Manufactures and Commerce (RSA): “RSA Animate - The Secret Powers of Time”:http://www.youtube.com/watch?v=A3oIiH7BLmg “RSA Animate - Crises of Capitalism”:http://www.youtube.com/watch?v=qOP2V_np2c0

June 30, 2010 · 1 min · Hagen Paul Pfeifer

Nothing Absorbing, Just Hacking

Nothing really interesting these evening - just the usual hacking session. Linus is back from vacation and pent-up patches should be soaked up the next days. Eric submitted one patch after the other and the comment of Davem take the biscuit: “Slow down Eric, you’re on fire :-)”. Mathieu Lacage - let’s call him the ns-3 main developer ;-) - posted a patch where he fixed a uninitialized memory access, spotted by valgrind....

June 28, 2010 · 2 min · Hagen Paul Pfeifer

Unjoyous OO Python

Today I spend some hours to complete a python project. Because the project should expandable and manageable the functionality is splitted into classes, packages and so on - python best practices. But, as long as I program with python I don’t understand why this language is so hyped! Several years back I wanted to leave Perl as the scripting language of choice (sometimes I still use Perl). As far as I remember I looked at Python and Ruby and finally I decided to use Ruby....

June 26, 2010 · 2 min · Hagen Paul Pfeifer

Computer Weekend and ...

Münchner Stadtlauf as a distraction (but only 10 kilometers). PS: the compiler optimization patch is now mainline.

June 25, 2010 · 1 min · Hagen Paul Pfeifer

TCP Window Scaling and SYN Cookies

During some off-line discussion with Florian - one of the main developers of TCP SYN cookies - I was a little bit skeptic about the mechanism and the interplay with the TCP window scaling option. First I will describe these two mechanism; later on I will discuss their relationship and interplay. At the end I will discuss the regression and possible solutions. I shifted this off-line discussion to the kernel ml because it is not that trivial as it sounds....

June 24, 2010 · 6 min · Hagen Paul Pfeifer

'IETF: TCP Authentication Option'

Just now, two new Request for Comments are now online available: “RFC 5925”:http://www.rfc-editor.org/rfc/rfc5925.txt - The TCP Authentication Option “RFC 5926”:http://www.rfc-editor.org/rfc/rfc5926.txt - Cryptographic Algorithms for the TCP Authentication Option (TCP-AO) These two standards (and probably upcomming enhancements in several years ;) are the replacement for TCP MD5 Option (RFC 2385). TCP-AO specifies stronger Message Authentication Codes to protect against replay attacks for long lived connections like BGP sessions. It is a generic contaier where other authentication codes can be used....

June 22, 2010 · 1 min · Hagen Paul Pfeifer

Finally BPF Optimization Is On The Run

Yesterday I submitted all patches, one for linux-kernel and one for netdev. Normally git send-email saves me and automatically cc all stakeholders (if you construct you patch correctly) but this time I missed the whole kvm maillingslist and all involved stakeholders - shit happens. ;-) I furthermore asked davem how about to use of a special, but proprietary gcc extension. As I think we can gain some performance gains if we permit this extension - let’s wait and see …

June 21, 2010 · 1 min · Hagen Paul Pfeifer

Munich Symphony Orchestra stage The Lord of the Rings

The “Munich Symphony Orchestra”:http://www.muenchenevent.de/veranstaltungen/Der_Herr_der_Ringe-1825.html will perform during Apil 2011 the Lord of the Rings Epos with chorus, soloists and more then 250 assistants - sounds great! PS: http://www.youtube.com/watch?v=R-4nH1ajQJY

June 21, 2010 · 1 min · Hagen Paul Pfeifer

How to Cc in Patches

Nearly 99 percent of all kernel patches touch someones code. Someone is often the maintainer of the subsystem or another developer who is responsible for special tweaks. So the patch should not limited to some maillinglist but should also be addressed directly to the stakeholders of the code. If you are familiar with the current subsystem you know how is the stakeholder and it easy to Cc the right people. On the other hand if you are working within complete unfamiliar code it is not that easy....

June 19, 2010 · 1 min · Hagen Paul Pfeifer

Source Code Management to the finest, git

I never realized it because it is courteous in open source projects with more then one programmer to write a meaningful commit message (this is no matter of course in commercial projects). I just noticed that git prints the following message: # Please enter the commit message for your changes. Lines starting # with '#' will be ignored, and an empty message aborts the commit. # On branch kvm-accelerator [...] Quite nice … ;)

June 19, 2010 · 1 min · Hagen Paul Pfeifer