The Apple Newton, or simply Newton, is an early line of personal digital assistants developed and marketed by Apple Computer (now Apple Inc.) from 1993 to 1998. Some electronic engineering and the manufacture of the Newton was done in Japan by Sharp. The original Newtons were based on the ARM 610 RISC processor and featured handwriting recognition software. Apple's official name for the device was "MessagePad"; the term "Newton" was Apple's name for the operating system it used (Newton OS), but popular usage of the word Newton has grown to include the device and its software together. The name is an allusion to Isaac Newton's apple.