---
title: "Pluri-Forth"
id: 51754
type: "computer_media"
slug: "pluri-forth"
url: "http://localhost/computer_media/pluri-forth/"
markdown_url: "http://localhost/computer_media/pluri-forth.md"
published_at: "2023-08-13T23:14:30+00:00"
modified_at: "2026-04-04T08:23:14+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2022/04/20230809-041332.jpg"
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."
category:
  - name: "Archived Media"
    slug: "archived-media"
    taxonomy: "category"
    url: "http://localhost/category/archived-media/"
post_tag:
  - name: "Downloadable"
    slug: "downloadable"
    taxonomy: "post_tag"
    url: "http://localhost/tag/downloadable/"
  - name: "Tree Systems of Grand Rapids"
    slug: "tree-systems-of-grand-rapids"
    taxonomy: "post_tag"
    url: "http://localhost/tag/tree-systems-of-grand-rapids/"
  - name: "TS 1000"
    slug: "ts1000"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts1000/"
model:
  - name: "Timex/Sinclair 1000"
    slug: "ts-1000"
    taxonomy: "model"
    url: "http://localhost/model/ts-1000/"
genre:
  - name: "Forth (programming language)"
    slug: "forth-programming-language"
    taxonomy: "genre"
    url: "http://localhost/type/forth-programming-language/"
  - name: "Programming"
    slug: "programming"
    taxonomy: "genre"
    url: "http://localhost/type/programming/"
media_type: "ROM"
download_url: "https://archive.org/download/timex-sinclair-software-archive/Pluri-Forth (1983)(Tree Systems)(US)(TS1000)(ROM).zip"
mediadate: "1983"
producer_company:
  - id: 11409
    title: "Tree Systems of Grand Rapids"
    type: "company"
    url: "http://localhost/company/tree-systems-of-grand-rapids/"
related_products:
  - id: 13597
    title: "Pluri-Forth"
    type: "product"
    url: "http://localhost/product/pluri-forth/"
media_type_tags: "Forth (programming language), Programming"
---

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.