---
title: "Pluri-Forth"
id: 13597
type: "product"
slug: "pluri-forth"
url: "http://localhost/product/pluri-forth/"
markdown_url: "http://localhost/product/pluri-forth.md"
published_at: "2019-11-30T06:43:16+00:00"
modified_at: "2026-03-22T13:28:24+00:00"
author: "David Anderson"
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excerpt: "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…"
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  - name: "Soft Magic Corp."
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  - name: "Tree Systems of Grand Rapids"
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author_2: "Bob Alsum"
company:
  id: 11409
  title: "Tree Systems of Grand Rapids"
  type: "company"
  url: "http://localhost/company/tree-systems-of-grand-rapids/"
date: 1983
rarity: "Uncommon"
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  - id: 25772
    title: "A FORTH Primer"
    type: "article"
    url: "http://localhost/article/a-forth-primer/"
  - id: 24169
    title: "Forth"
    type: "article"
    url: "http://localhost/article/forth/"
  - id: 24414
    title: "Programming Your Computer"
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  - id: 36662
    title: "FORTH Corner"
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  - id: 36761
    title: "Forth Corner"
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  - id: 24025
    title: "The Forth Corner"
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  - id: 24031
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  - id: 24038
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    title: "4th Corner"
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    title: "4th Corner"
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  - id: 36778
    title: "4th Corner"
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    title: "Tree-Forth"
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    title: "Hardware Review: MultiForth EPROM Chip"
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  - id: 16101
    title: "Unknown Tongues Alternative Computer Languages"
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  - id: 47701
    title: "Tree-Forth manual"
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  - id: 54805
    title: "Tree-Forth manual"
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    url: "http://localhost/document/tree-forth-manual-2/"
product_reviews:
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    title: "Hardware Reviews"
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  - id: 65983
    title: "Tree-Forth Users SIG Notice"
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    title: "Pluri-Forth"
    type: "computer_media"
    url: "http://localhost/computer_media/pluri-forth/"
companies_products:
  - id: 11409
    title: "Tree Systems of Grand Rapids"
    type: "company"
    url: "http://localhost/company/tree-systems-of-grand-rapids/"
  - id: 11311
    title: "Soft Magic Corp."
    type: "company"
    url: "http://localhost/company/soft-magic-corp/"
---

# Pluri-Forth

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 between Forth and Basic.

Pluri-Forth was supplied as a 2764 8K EPROM chip/carrier board with a socket for the Sinclair (or another 8K EPROM). The 104 page manual served as an introduction for FORTH. [Tree Systems](http://localhost/company/tree-systems-of-grand-rapids/) manufactured and sold it, initially as Multi-Forth. [Soft Magic Corp](http://localhost/company/soft-magic-corp/) also sold it as Tree-Forth.

### Versions

[Robert Trelease reviewed version 2.3](http://localhost/article/forth/), based on his screen capture. A photo of the ROM installed in another system is marked v3.0.