Copyright 1999-2000 by Andrew Plotkin. You have permission to display, download, and print this document, provided that you do so for personal, non-commercial use only. You may not modify or distribute this document without the author's written permission.
However, the virtual machine described by this document is an idea, not an expression of an idea, and is therefore not copyrightable. Anyone is free to write programs that run on the Glulx VM or make use of it, including compilers, interpreters, debuggers, and so on.
This document and further Glulx information can be found at: http://www.eblong.com/zarf/glulx/