Brief: Umbilical Development for Small Targets

An interesting development from Microsoft robotics team.

They appear to have pulled together a lot of ideas together that have been in use in commercial Forth systems for 25 years and added some cutting edge Forth ideas.

- implicit call bit. Important to manage code size in Forth where calls are used a great deal. (1st seen in Chuck Moore's silicon designs)

- sub-routine threading: faster than in-direct or direct threaded code

- tail call optimization, not often seen in Forth compilers

- umbilical architecture: compiler on host/code on target

- consistent RPN syntax

- quotations. Not standardized in Forth but implemented in multiple ways in various systems.