CollapseOS port, written in Tal
Fixed issue with SFT
Ported to latest Uxn


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You can also use your local clone with git send-email.

#Collapse OS

Bootstrap post-collapse technology

Collapse OS is a Forth operating system and a collection of tools and documentation with a single purpose: preserve the ability to program micro- controllers through civilizational collapse.

It it designed to:

  1. Run on minimal and improvised machines.
  2. Interface through improvised means (serial, keyboard, display).
  3. Edit text files.
  4. Compile assembler source files for a wide range of MCUs and CPUs.
  5. Read and write from a wide range of storage devices.
  6. Assemble itself and deploy to another machine.

Additionally, the goal of this project is to be as self-contained as possible. With a copy of this project, a capable and creative person should be able to manage to build and install Collapse OS without external resources (i.e. internet) on a machine of her design, built from scavenged parts with low-tech tools.

#Getting started

Documentation is in text files in doc/. Begin with intro.txt.

Collapse OS can run on any POSIX platform and builds easily. See cvm/README for instructions.

#Organisation of this repository

  • blk.fs: Collapse OS filesystem's content. See below.
  • cvm: A C implementation of Collapse OS, allowing it to run natively on any POSIX platform.
  • doc: Documentation. Begin with intro.txt.
  • arch: collection of makefiles that assemble Collapse OS on different machines.
  • tools: Tools for working with Collapse OS from "modern" environments. For example, tools for facilitating data upload to a Collapse OS machine through a serial port.
  • emul: Tools for running Collapse OS in an emulated environment.
  • extras: Forth code designed for running in Collapse OS but that are beyond the scope of its design goals. See extras/README.


This file is a big text file containing the "real deal", that is, the contents of Collapse OS' filesystem. That filesystem contains everything that a post-collapse computer would manage, that is, all Forth and assembler source code for the tools it needs to fulfill its goals.

The Collapse OS filesystem is a simple sequence of 1024 bytes blocks. That is not very workable in the text editor of a modern system. blk.fs represents an "unpacked" view of that block system. Each block (16 lines max per block, 64 chars max per line) begins with a marker indicating the block number of the contents that follow.

Blocks must be in ascending order.

That file can be "packed" to a real blkfs with /tools/blkpack. A real blkfs can be "unpacked" to its text file form with /tools/blkunpack.

#Version control

To allow a deeper understanding of the code, changes to Collapse OS' source is kept under RCS. Unlike most uses of version control systems, the goal here is not to be able to branch or to checkout specific revisions: tarballs snapshots can be used for this.

The goal is to keep a record of changes and their rationale, in case someone examining the code wonders about such things. To that end, only the "real deal" is versioned, that is "blk.fs".

Other source files (CVM, emulators, tools) are considered accessory and are not version-controlled.

RCS versioning begins at 2021-01-05. Previously, versioning was done through Git. An archive of that git repository is available on Collapse OS' website.

#Emulation and dogfooding

Emulation used to be a central tool to developing new ports for Collapse OS. On a POSIX platform, I would begin by creating an emulator for my target machine, fool around, then when I thought I had something good, test on real hardware for adjustments.

With the 6809 port, I wanted to take dogfooding more seriously and began developing ports from Collapse OS itself on vintage machines. This allows me to see opportunities for usability improvements and detect bugs much better than when using a POSIX platform.

Because of that, the "emul" folder is no longer improved.

#Looking for the assembler version?

The Forth-based Collapse OS is the second incarnation of the concept. The first one was entirely written in z80 assembly. If you're interested in that incarnation, checkout the z80asm branch in the Git archive.