Yes, this is yet another Linux distribution. What's different here is that Puppy is extraordinarily small, yet quite fully featured. Puppy boots into a 48M ramdisk, and that's it, the whole caboodle runs in RAM. Unlike live CD distributions that have to keep pulling stuff off the CD, Puppy in his entirety loads into RAM. This means that all applications start in the blink of an eye and respond to user input instantly.