In the GCaP class earlier this month, we talked about the meaning of the load average (in Unix and Linux) and simulating a grocery store checkout lane, but I didn't actually do it. So, I decided to take a shot at constructing a discrete-event simulatio...

One of my gripes about some commercial load testing tools is that they only provide a think time distribution (Z) that is equivalent to uniform variates in the client-script. If you want some other distribution, you have to code it and debug it yoursel...

I was planning to blog about the amazing time I had at Velocity 2009 last week, when this landed in my mailbox (edited for space and privacy): Subject: Seeking help with PDQ-R ...Date: Thu, 25 Jun 2009 15:51:21 -0500My name is James and I've be...

PDQ (Pretty Damn Quick) major release 5.0 is on the launch pad at Cape SourceForge. Because of a potential collision with the North Korean ICBM/satellite launch, we won't be filling the main liquid-hydrogen tank until next week (we don't want PDQ blame...

One the nice things about PDQ-R (coming in release 5.0) is the ability to plot PDQ output directly in R. Here's a PDQ-R script, together with the corresponding graphical output, that I knocked up to show the effect on the throughput curve of adding mor...

After some fiddling to get things linked correctly to the R binaries on my new Macbook, the first PDQ-R test model has run successfully! Here 'tiz ...This is an important step for PDQ development and is due entirely to the efforts of Phil Feller. Natur...