Tree Systems of Grand Rapids

3645 28th St, Grand Rapids, MI 49608

Bob Alsum, owner.


Pluri-Forth is both an operating system and a programming language, replacing the Sinclair ROM entirely. FORTH programs were compiled and ran about 10 times faster than interpreter BASIC. Pluri-Forth offered multitasking, a feature not available in Basic. When used with the Sinclair ROM, the channel 2/3 switch is wired to the Pluri-Forth board to select
Downloadable TS 1000
Word processor written in Forth, for use with Pluri-Forth.
TS 1000


  • Forth
    Overview of Forth and review of Tree Systems PLURI-FORTH EPROM.
  • Hardware Review: MultiForth EPROM Chip
    Review of Tree Systems’ Forth EPROM, comparing it to IPS Forth.
  • The Forth Corner
    Introduction to Forth and review of Pluri-Forth from Tree Systems.
  • The Forth Corner
  • TreeForth
    Source code for TreeFORTH (a ROMable, TS1000, slightly non-standard FORTH) has been released for non-commercial use by author Bob Alsum.


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