(c) Garry Lancaster, 2001
Z88 CamelForth is a version of the Forth language, based on the minimal Z80 CamelForth v1.2 implementation by Bradford J. Rodriguez, with many enhancements, and now fully ANS-compliant.
The version described and available here, as at 17/7/01, is v3.04. The screenshot above shows the operation of a short multiprogramming demo (source included with the downloads), with three tasks being run in separate windows, and a Forth terminal accepting input in a fourth (sorry, pun intended!)
Full updated sources of Z88 CamelForth, including ports to other systems like the Spectrum and Sprinter are available here: http://bitbucket.org/garryl/camelforth/
If you know nothing about Forth, but would like to learn, an excellent source of information in the Fig-UK website.