The Smalltalk Virtual Machine is a Virtual Machine that allows a Smalltalk image to run on an underlying platform. The Smalltalk Virtual Machine executes compiled methods whose code is expressed as Byte Code sequences. It includes a process model, stack-frames, closures (sort of), and a variety of debugging hooks.
The Blue Book described an early Smalltalk Virtual Machine, no corresponding Virtual Machine was ever actually built. The early Smalltalk Virtual Machines, built by Xerox, varied from the Blue Book in significant ways.
Later versions diverged even more dramatically, including the "HPS" implementation that supported Just In Time Compilation, various compiler optimizations, and several varieties of bit-mapped graphics magic.
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