The operating system for a mobile device. There are several device manufacturers that use this operating system.

The PalmOS is the operating system utilized by the Palm computing devices. Palm OS was designed to fit into a palm-sized device of a specific size and with a specific display size. Palm OS comes with communication interfaces to infrared devices, TCP/IP (for Web connection through wireless or wireline devices). Other OSs include Windows CE and EPOC.

Palm OS is the computer operating system that provides a software platform for the PalmPilot series of handheld personal digital assistants made by Palm Computing. Palm OS was designed from the beginning to fit into a palm-size device of a specific size and with a specific display size.