The Geeky Junkyard of kingler

Last weekend, I went to WordCamp 2007 in San Fransisco. In case you didn’t get the news, WordCamp is the annual gathering of WordPress bloggers and developers. This year’s event was packed with 2 days of great talks, but I only got the chance to attend the second day, which focused on developers and the future of WordPress. George, however, attended the first day and mentioned that the talk on SEO tips given by Matt Cutts from Google was pretty good. Wish his slides were published somewhere.

As a WordPress plugin developer and also a wp-hacker, I was quite excited about the technical stuff the core WP developer team talked about during the second day.

The first talk(view the slide here) was from Barry and Matt. Barry, the sysadmin, mentioned some amazing stats from WordPress.com and talked about the performance tuning, like APC and WP-CACHE. Matt then introduced HyperDB, the failsafe/redundant/cluster MySQL database class used in the WordPress.com backend. Although I am on the HyperDB maillist since day one, I was having doubts about HyperDB. However, from what Matt talked about, HyperDB does actually many things that I have in mind. Coupled with the new MySQL Proxy, High Availability WordPress clusters would be much easier to build now.

[to be continued...]

National Instrument High Speed DIO drivers can read and write a specialized file format HWS (Hierarchical Waveform Storage). It is actually a subset implementation of the famous HDF5, which is best data format for large scientific data (we are talking about terabytes here).

Anyway, as I started playing with .hws file a bit more, I found it quite easy to use, and because it is based on HDF5, I can use any software that supports HDF5 to open the HWS file! And, no surprise here, MATLAB, from ver 6.5, has functions to read and write HDF files.

However, MATLAB’s hdf5read() function requires an unique dataset attribute for the data that you want to load from the HDF5 file. So, to read the NI-HWS file, we need to figure out the dataset attribute. Using HDF Explorer and HDF Viewer application, I was able to find the correct attribute to read the HWS file in MATLAB. Here it is

hdf5read('test.hws','/wfm_group0/axes/axis1/data_vector/data');

The second paramter is the HDF5 attribute for the actual dataset in the HWS file.

The other day, one of our lab engineers brought an old book over. It is the 1968 Trident! In case you are too young to know the name (just like me), Trident is the Year Book for graduates of UCSD at that time.

1968 is actually a very important year in the history of UCSD. The first undergraduate class of UCSD was admitted in 1964, so 1968 was the first class of UCSD graduates! Anyway, the photo below is the campus photo. At that time, only Revelle College was there. In the 40 years after this photo was taken, UCSD has grown to 6 colleges and more than 20000 students. What an accomplishment!

More history of UCSD on TritonLink?

For comparison, you can take a look at the recent satellite and aerial images. Google Maps, and Microsoft Live Local, or the official UCSD Maps.

To improve the PHP performance, I started playing with APC (Alternative PHP Cache) and memcached recently. However, to install the APC extension and PHP-Memcache client on Debian Sarge turned out to be not that trivial. Here I’d like to share my experience. It serves as my own personal record as well.
First of all, you need to have PHP4-dev and Pear package installed on your system:

apt-get install php4-pear php4-dev

In order to use the ‘pecl’ installation tool, you need to upgrade the bundled PEAR version to the latest:

pear upgrade pear-1.3.3
pear upgrade Archive_Tar
pear upgrade Structures_Graph
pear upgrade pear
pear upgrade-all


After the upgrade, you need one more step before proceeding with the pecl installation. If you don’t do the following you will have the error like this when compiling php-memcache: (configure: error: Cannot find php_session.h). Thanks to this post, I found the solution: you need to create the following symoblic link:

ln -s /usr/include/php4 /usr/include/php

Okay, final step is easy:

pecl install apc memcache


For APC, you may just choose not to compile with aspx-support, if it prompted you to select.

Now sit back, and wait for the compilation to finish. After it is done, you just need to enable the modules in your PHP.ini configuration file, which I am not going to touch upon here.

Good luck with your optimization for PHP code.