I installed python-matploglib and python-mpltoolkits.basemap using apt, but when I tried to import Basemap using from mpltoolkits.basemap import Basemap, the following warning shows up:

usr/lib/pymodules/python2.7/mpl_toolkits/__init__.py:2: UserWarning: Module dap was already imported from None, but /usr/lib/python2.7/dist-packages is being added to sys.path
  __import__('pkg_resources').declare_namespace(__name__)

rake generate can take quite a while, especially when you have many blog posts. Here are a few tips on how to speed up the generation process.

I used to blog on wordpress.com. After a year or so, I finally decided to abandoned it and switched to Octopress + Github Pages. Here are the reasons and how I migrated to Octopress. Maybe because I was using wordpress.com, and those who use a self-hosted wordpress have something different to say, the way I see it, wordpress, at least wordpress.com, sucks.

The idea of Reader-Writer Lock is quite simple. In normal lock, we don't differentiate the threads. That said, each thread who wants to enter the critical section must first acquire the lock. But on a second thought, you may find that threads actually have different behavior inside the critical section: some threads just want to see the values of shared variable, while others really want to update those variables.

Condition variable is used for a thread to wait for some condition to be true before continuing. The implementation is quite simple compared to lock, yet the difficult part is to understand how a CV is supposed to used.

Lock is basically just a semaphore whose initial counter is 1. lock_acquire is like P, while lock_release is like V. You probably want to go over my previous post about semaphore

Semaphore denotes a certain number of shared resources. Basically, it's one counter and two operations on this counter, namely P and V. P is used to acquire one resource (thus decrementing the counter) while V is used to release one resource (thus incrementing the counter).

If you're Vim user, then you must try Vimium. It makes your browsing much much comfortable!

When you finished the process system call (e.g., fork, execv) and test your system call by executing some user program, you'll probably find that the console input behavior is messed up.

Suppose we use cscope and/or ctags for indexing source code of our Java project and we want to update the meta data files (e.g. cscope.out, tags) each time after we compile. We can use the --post-comile target to accomplish this. Create a custom_rules.xml in your project root directory with the following content. This file will be included to your main build.xml file.