Mysterious 501 error responses and WebSEAL

This is just a quick post for future reference. Hopefully, it can help others in figuring out why a service behind Tivoli Access Manager's WebSEAL is returning a 501 error from POST requests. Recently, I wrote a client using Apache's HttpClient for accessing a REST API protected by IBM's WebSEAL 6. While uploading data via POST, I started receiving a mysterious 501 Not Implemented error. The data in question was being uploaded with chunked encoding, as in the following snippet1.

Making the Playstation Eye’s microphones work on Linux

Introduction I'm the proud owner of a PlayStation® Move system and also a proud user of the Arch Linux distribution. As much as pride is concerned, it's not very “proudful” when you decide to give your PlayStation® Eye (PS3 Eye) a try as a webcam, and you realize it doesn't quite work as you expected. This post investigates this issue and proposes a solution. Even though the PS3 Eye is supported by Linux 2.

Please, don’t use exit(-1)

Introduction In the past two weeks I saw a few cases where programmers were telling their programs to exit(), but without fully understanding what their exit codes meant and how they were represented. In this post I'll explain what I believe to be the right way of doing it. The first time I started to think about this was when I saw a script similar to the one below. But what really motivated my was [this reddit thread][].

Cognitive biases

Ever since I first heard about the Dunning-Kruger effect, I've started observing a bit more how I and some other people behave. Last week a friend introduced the “Impostor syndrome” concept to me, a “syndrome” apparently common among graduate students. There's a very interesting article that presents the concept nicely, and which I quote here: “Impostor syndrome” is the name given to the feelings that Abigail and many other young scientists describe: Their accomplishments are just luck or deceit, and they're in over their heads.

One month and a half in the Summer of Code program

It's been a month and a half since I started working on the Mercurial project as part of the Google Summer of Code program. Mercurial is a free, distributed source control tool written in Python that efficiently handles projects of any size and offers an easy and intuitive interface while the Google Summer of Code is a global program that offers student developers stipends to write code for various open source software projects.