Puppy Linux is a lightweight Linux distribution designed to be easy to install and use. Puppy is small (the live-CD is less than 100MB) and loads completely into RAM, which also makes it fast. Puppy has very low system requirements making it a suitable open source operating system for older PCs and in netbooks. This open source operating system is bundled with a number of applications for general use including word processor, spreadsheet, Internet browser, games, image editor and other utilities.
Puppy Linux was created by Barry Kauler who released version 0.1 in June 2003. Today, the Puppy-project is a team effort.
See What is Open Source Software and Linux Downloads: Top Linux Distributions in Webopedia’s Did You Know…? section.