PIVOS

PIVOS is a multitasking Forth-based operating system designed for the 8086 based IBM-PC that places an emphasis on user control, error handling, and human-scale system design. It is highly inspired by the philosophy of permacomputing. It is not attempting to compete with a full modern operating system, such as Linux, nor be POSIX compatible in any sense; rather, it is attempting to provide an alternative to a traditional Forth System, such as FIG FORTH.

PIVOS aims to provide an ideal environment for experimenting and exploring the system. This necessitates the ability for one person to understand the entire system all at once; in this respect, PIVOS is inspired by operating systems like Unix. To make experimentation easier, a number of features are stripped: there is no filesystem, permission system, network manager, conventional command line, nor even a conventional kernel. There are no system calls, only an API provided directly within the Forth environment. Additionally, Machine Code and Forth can be intermixed arbitrarily with little effort, when desired.

HISTORY AND INSPIRATION

In July of 2023, mjm and ote began working on PIVOS. The project was dropped around a week later, picked up in January of 2024, dropped a second time, picked back up in July of 2024, dropped a third time, and finally picked back up again in November of 2025. It is currently under development.

PIVOS was primarily formed out of dissatisfaction with modern systems that are too complicated to fully understand, designed to sabatoge any attempt at repair or editing, and generally restrict the user from doing what they desire to. Try to understand every driver currently active on your system, and you will discover several different code obfuscation techniques. PIVOS draws its inspiration from traditional Forth Systems, as well as personal computers of the 80s and 90s, but with a modern perspective on robustness and error handling.

In the potential future, once the operating system is completed, there are plans to design a stripped down PC as a keyboard computer, port PIVOS to other architectures, and implement a Smalltalk dialect on top of PIVOS.

DESIGN PRINCIPLES

• The user calls the shots. Assume the user is fallible, but competent. Any interaction that might be ruled out as a sure-fire mistake will become central to a future system. There ought to be safety mechanisms to prevent the system from accidentally being destroyed, but the user must also be able to overwrite them.
• Always have a recovery plan. It is not a matter of if code will fail, but when it will fail. Error cases must always be taken into consideration, never dismissed. The machine must remain operable even in the most dire of circumstances. If there is no internet, the system must still function. If the disk fails, the system must still function. Even if every step after the initial boot fails, the system must be salvageable. Any time saved by removing a safety check will be negated when that case is encountered.
• Design to be understood. Simple code is easy to debug. Clever code is a problem to debug. It must be possible for the user to comprehend every single detail of the system at once.

FONTS

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