The Drupal throttle module became a part of the core distribution in Drupal 4.1, released in February of 2003. It was originally written for the Drupal powered technical website, KernelTrap.org, which at the time was running on a single Pentium I CPU with a 100 megabit connection to the Internet. KernelTrap was receiving regular links from Slashdot.org, and the slow processor was simply unable to keep up with the load, succombing to a "Slashdotting".
The solution at the time was to ssh into the server and manually disable all modules which where not strictly necessary, until the link moved further down the Slashdot front page and the server could again keep up. The throttle module was written to automate this process, quickly detecting when the website came under a heavy load and automatically disabling unnecessary functionality, then re-enabling it when the load subsided.
As we will learn later in this chapter, the throttle module is little more than a bandaid, attempting to work around a problem rather than solving it.