a proprietary operating system for personal computing devices, including personal digital assistants (PDAs), “smart phones” (telephones with PDA-like features), handheld gaming systems, and Global Positioning System (GPS) (GPS) devices. More than 17,000 applications have been created for the Palm OS by licensed developers.

American inventor Jeff Hawkins founded Palm Computing, Inc., in 1992, developing application software for early PDAs. After Palm merged with U.S. Robotics in 1995, Hawkins led the development of Palm OS for his line of PDAs, first marketed as Pilots, then as Palm Pilots, and eventually as Palms. In 1997 the 3Com Corporation purchased U.S. Robotics, including Palm Computing, Inc. Key software that featured in all versions of the platform includes Hotsync, for facilitating synchronization between the device and a computer, and Graffiti, a handwriting recognition system for which the Xerox Corporation successfully sued Palm for patent infringement in 2006.

Palm's line of PDAs won many awards, and, at the turn of the 21st century, the Palm OS dominated nearly 70 percent of the global market for handheld computing devices. However, the market for PDAs soon turned to smart phones, such as the BlackBerry, which was introduced by the Canadian company Research in Motion in 2002. Thus, in 2002 Palm created a subsidiary, PalmSource, to license the operating system, while the parent company shifted focus to wireless mobile telephone technology. PalmSource became an independent entity in 2003, with Palm Computing becoming a licensee of the Palm OS. In 2005 PalmSource was acquired by ACCESS Co., Ltd., a Japanese technology company, but the right to use the Palm OS and exclusive rights to the Palm OS brand name were subsequently retained in the deal by Palm Computing. As a consequence, in 2007 ACCESS changed the name of its system from Palm OS Garnet to Garnet OS. A variety of smart phones and handheld computing devices are built on the Garnet OS.