I remember the Apple Newton, mine took 4 AA battery's and did very adequate handwriting recognition. From wikipedia: The original handwriting recognition engi

I remember the Apple Newton, mine took 4 AA battery's and did very adequate handwriting recognition. From wikipedia: The original handwriting recognition engine was called Calligrapher, and was licensed from a Russian company called Paragraph International. Calligrapher's design was quite sophisticated; it attempted to learn the user's natural handwriting, using a database of known words to make guesses as to what the user was writing, and could interpret writing anywhere on the screen, whether hand-printed, in cursive, or a mix of the two. By contrast, Palm Pilot's Graffiti had a less sophisticated design than Calligrapher, but was sometimes found to be more accurate and precise due to its reliance on a fixed, predefined stroke alphabet. The stroke alphabet used letter shapes which resembled standard handwriting, but which were modified to be both simple and very easy to differentiate.[..] For editing text, Newton had a very intuitive system for handwritten editing, such as scratching out words to be deleted, circling text to be selected, or using written carets to mark inserts.[5] Later releases of the Newton operating system retained the original recognizer for compatibility, but added a hand-printed-text-only (not cursive) recognizer, called "Rosetta", which was developed by Apple, included in version 2.0 of the Newton operating system, and refined in Newton 2.1. Rosetta is generally considered a significant improvement and many reviewers, testers, and most users consider the Newton 2.1 handwriting recognition software better than any of the alternatives even 10 years after it was introduced.[6] Recognition and computation of handwritten horizontal and vertical formulas such as "1 + 2 =" was also under development but never released https://en.wikipedia.org/wiki/MessagePad#Handwriting_recognition https://en.wikipedia.org/wiki/MessagePad#Handwriting_recogni...