MallowOS: A Workstation Operating System

What is MallowOS?

MallowOS is an operating system designed for workstation users that is based on 9legacy, a collection of updated patches for Plan 9 from Bell Labs, and will have a user interface this is largely compliant with the classic Macintosh Human Interface Guidelines, except where non-compliance is necessary to achieve MallowOS's principles.

MallowOS's principles are:

MallowOS is inspired by the following systems:

The vision of MallowOS is heavily derived from the thoughts expressed in this blog post from April 2020, though some of the design decisions expressed in that document have changed; the blog post should not be interpreted as MallowOS's canonical design document, but should be read as a manifesto of what a workstation operating system should be.

Why Plan 9 instead of Linux or one of the BSDs?

In Plan 9, system resources such as user processes and the rio window system are available through the standard file system interface. One of the benefits of this design is that programs can access system resources regardless of the language they're implemented in, removing the need for language-specific wrappers. User applications such as acme also present themselves to the system with a file system interface, facilitating the principles of composability, interoperability, malleability, and programmability. This makes Plan 9 an ideal substrate to implement MallowOS; it will take less time to implement MallowOS on top of Plan 9 than it would to implement the necessary middleware features to implement MallowOS on top of Linux or the BSDs.

The idea of using Plan 9 as a substrate came about after reading Stephen Kell's paper Unix, Plan 9, and the Lurking Smalltalk. Originally MallowOS was an exploration of what a Smalltalk- or Lisp-based operating system with a Mac OS 9-style user interface would be like, but the shift to Plan 9 was motivated by a desire to base interoperability on language-agnostic protocols instead of requiring software to use some type of object middleware such as COBRA, dbus, or a VM like Microsoft .NET or the JVM.

Of course, Plan 9 does not have the amount of drivers and third-party software that Linux and the BSDs have, which may hinder initial adoption of MallowOS. However, if MallowOS becomes popular, then this will encourage the development of drivers and third-party software.

When and how will MallowOS be available?

As this is a side project, MallowOS won't be available until most likely sometime in the second half of 2024. However, this page will be updated as system development progresses.

MallowOS and its components will be under the BSD, MIT, or similar licenses.

Why the name MallowOS?

Mallow is a pale shade of purple, and the color choice was inspired by the history of the Pink/Taligent project, which also inspired the name of another operating system, Fuchsia. The word "mallow" also sounds a lot like "malleable," one of the design prinicples of MallowOS.

This page was last updated by Michael McThrow on August 21, 2022.