All distributions are different, but Puppy Linux [1] is more so than most. In fact, some who develop or use Puppy Linux assume from past experience that media coverage of the distribution will inevitably misrepresent it. The truth is, Puppy Linux is not a single operating system, not even one with multiple editions, flavors, or spins. Instead, Puppy Linux is a collection of lightweight operating systems built on common code with some common applications and a few points of common philosophy (Figure 1) – rather as though Debian, Ubuntu, and Linux Mint were all part of the same project. Little of this definition of Puppy Linux is spelled out. As a result, most reviews of Puppy Linux concentrate on the more popular Puppy operating systems, which makes most reviews misleading.

Puppy Linux was founded by Barry Kauler in June 2003. Kauler's efforts were a response to the increasing hardware requirements of other distributions. From early on, the Puppy Linux Discussion Forum was central to the distribution, and it remains so to this day. However, Puppy only began to assume its current form in its third release. The third release included both a remastering app that allowed users to select what they compiled and the forerunner of Woof, which allows Puppy's infrastructure to be used with the binary of another distro – today, usually Slackware or a specific Ubuntu or Debian release. Using Woof, a user called Jemimah added the third distinguishing feature of Puppy: the ability to load drivers, firmware, and kernels into RAM, which not only increased the speed but simplified updates (Figure 2).

With this structure, Puppy Linux assumed most of its present forum, with features such as Woof that are common to all Puppy distributions, and other features that are unique to a particular distribution. Today, Puppy Linux recognizes three different types of distributions:

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