As my junior high school buddy once said...

…you know something’s really funny when Coke sprays out of your nose.

I’m coming to it late, I know, but Eric Schmidt’s Serenity Prayer made me laugh out loud, disconcerting the other coffee shop patrons.

Bloviationism

From the New Republic:

Clintonism is a political strategy that assumes a skeptical public; Obamaism is a way of actualizing a latent ideological majority.

Nice to know that jargon cuts across professional lines. Now, back to that RESTful interface to DE9IM topological relations…

Benchmarks, Damn Benchmarks and Statistics

Seen on the #mapserver IRC channel:

“hey guys I have mapserver running fine on a vehicle tracking application, what I want to know is the requirements for mapserver. Let say 100 connections on the same time. I have 2 GB RAM , Dual Core 3GHz procesor, what do you say, Will it be enough?”

Well, enough for what? At least one variable is missing, and that’s the expected response time for each request. If I am allowed to take a week per response, I can really lower the hardware requirements!

Benchmarking an application is a tricky business, and there are lots of ways to quantify the robustness of an application. My favorite method is a holistic method that takes into account the fact that most of the time the load generators are human beings. This won’t work for pure “web services”, where the requests can be generated automatically by a wide number of different clients.

Step one is to generate a baseline of what human load looks like. Working through your test plan is one way to achieve this, though you might want to game out in your head what a “typical” session looks like rather than a “complete” session that hits every piece of functionality once. Call this your “human workload”.

  1. Empty your web server logs.
  2. Sit down and run the “human workload” yourself, at a reasonable speed. You know the application, so you probably click faster than an average user, no matter, it doesn’t hurt to bias a little in the fast direction. When you are done with your session note the elapsed time, this is your “human workload time”.
  3. Now, take your web server logs and run them back against the server using a tool like curl. This generates all the requests from your human session, but forces the server to execute them as fast as possible. When it finishes, note the elapsed time, this is your “cpu workload time”.
  4. Finally, divide your “human workload time” by your “cpu workload time”. The result is how many computers like the one you just ran your test on are needed to support each human. If the answer is 0.2, then you can support 5 humans on your test machine.

Obviously, this is a very simple test metric, but it has the advantage of extreme ease-of-application and a tight binding between what is being measured and what the real world will finally hit the application with.

Blood Sucking Phone Company

So, I’m sitting in SeaTac, minding my own business, drinking a cup of tea (SeaTac travel tip: free WiFi at Tully’s coffee with purchase) and my phone rings. It is my (god forsaken, soul sucking, devil worshipping) cell-phone company. They want to give me a free phone! It’s quad band! It’s got a great camera! I’m a preferred customer, so it’s only $10 (for a $300 phone!) and comes with a second line.

Well, having been screwed before, my ears perk up. What is this second line, of which you speak? “Oh, you get unlimited minutes for three months, sir!” And after three months? “We can get you a couples package.” Well, fabulous. Another up-sell. Thanks, but no thanks, and take your fabulous phone with you.

It’s a good thing they weren’t offering me an iPhone, or I would have cracked.

O'Reilly on Open Source ... in 1999

It is more than a little disturbing that both the myths and the explanations in this nearly-10-year-old article have remained so constant. Here are the myths:

  • It’s all about Linux versus Windows, with Red Hat as yet another challenger to Microsoft.
  • Open Source Software Isn’t Reliable or Supported.
  • Big companies don’t use open source software.
  • Open Source is hostile to intellectual property.
  • Open Source is all about licenses.
  • If I give away my software to the open source community, thousands of developers will suddenly start working for me for nothing.
  • Open source only matters to programmers, since most users never look under the hood anyway.
  • There’s No Money to be Made on Free Software.
  • The Open Source movement isn’t sustainable, since people will stop developing free software once they see others making lots of money from their efforts.
  • Open Source is playing catch up to Microsoft and the commercial world.