The Apple Newton MessagePad 100 features a 20 MHz ARM 610 processor, 4 MB of ROM, 640k of RAM (150k usable), and infrared-beaming capabilities in a compact handheld case with a 336x240 pressure-sensitive monochrome display for use with a provided stylus. The Newton MessagePad 100 is effectively identicial to the original Newton MessagePad, but was less expensive, and shipped with a newer version of the NewtonOS (1.2) in ROM. The Newton MessagePad was one of the first series of handheld systems, or PDAs (Personal Digital Assistants), to attempt to recognize natural handwriting and use a basic form of artificial intelligence to 'tie' relevant information together. Please note that Newtons are technically not 'Macs', as they do not operate the MacOS, and instead use the NewtonOS (also developed by Apple).