ObsidianOS: A/B Arch Linux Done Differently

ObsidianOS: A/B Arch Linux Done Differently

Table of contents:-

What ObsidianOS Is

Design, Editions and Tooling

Experimental Overlays and Package Layering

What ObsidianOS Is

ObsidianOS is an Arch‑based GNU/Linux distribution that combines a UEFI‑only design, an A/B partition layout and Rust‑powered tooling to create a more resilient, rollback‑friendly desktop operating system for x86_64 systems. It is developed under the Obsidian‑OS GitHub organisation, which describes the project simply as “The GNU/Linux distribution with A/B Partitioning”, reflecting how central this concept is to the system’s identity.​

ObsidianOS is distinct from the Obsidian note‑taking application, although the project explicitly leans on that ecosystem’s ideas and branding, describing its goal as “turning Obsidian.md into an OS” and using the Obsidian logo as a placeholder symbol of that connection. The developers acknowledge that they do not own the Obsidian logo and present it instead as an indicator of inspiration and technical direction.​

Design, Editions and Tooling

At the heart of ObsidianOS is a genuine A/B partitioning scheme: the root filesystem is duplicated into two separate “slots”, and system updates are applied to the inactive slot so the user can boot back into the previously working root if something goes wrong. This approach echoes update strategies used in platforms like ChromeOS and Android, but ObsidianOS builds it on top of a conventional Arch‑style userspace and an EXT4‑by‑default storage stack, with an option to use F2FS at install time.​

The project offers multiple editions, including a minimal Base edition, a KDE edition that is positioned as the main or recommended desktop variant, and a COSMIC edition that is functional but still in a beta state. A GUI installer built with Qt6 and Python is available for the KDE and COSMIC editions, while the Base edition sticks to a more traditional text‑user‑interface installer for users who prefer or require a leaner setup. Installation media and scripts are distributed via the project’s file service, and there is also a scripted method to install ObsidianOS directly from an existing Arch Linux system using a curl‑driven installer entry point.​

Beyond the installer, ObsidianOS ships its own control and management tooling, including an obsidianctl command‑line tool and a graphical ObsidianOS Control Center built with Qt6 as a front end to that functionality. These tools aim to centralise common tasks such as managing updates, reviewing changes, inspecting logs and working with the A/B layout, so users do not have to juggle low‑level commands to benefit from the system’s design.​

Experimental Overlays and Package Layering

One of the most distinctive aspects of ObsidianOS is an experimental user‑mode overlay system implemented in Rust that intercepts libc calls to provide layered filesystem behaviour entirely in user space, without special kernel modules or non‑standard filesystems. This design lets the system present a writable overlay on top of the base root filesystem, enabling reversible changes and a more “sandboxed” feel for certain operations, while leaving the underlying base unmodified until the user explicitly commits changes.​

Building on that foundation, ObsidianOS introduces opm, the ObsidianOS Package Manager, also written in Rust, which works alongside pacman to deliver “overlaid packages”. When a package is installed through opm, it is obtained from the standard pacman sources but materialised into an overlay image that is then applied on top of the system rather than directly merged into the root. This layered approach is intended to reduce the risk that a problematic package or broken dependency chain will render the system unbootable, especially when combined with the A/B partitioning scheme that already separates active and updated roots.​

The same overlay mechanism underpins an experimental plugins system, referred to as ObsidianOS Plugins, which are Rust‑based scripts that respond to system events such as battery state changes. Together, user‑mode overlays, overlaid packages and event‑driven plugins give ObsidianOS an architecture that is unusually focused on reversible state and controlled change, which is particularly attractive for tinkerers and developers who routinely push their systems into new configurations.​

A test run of ObsidianOS has been performed by The Distrowrite Project on Virt Manager using the KDE Plasma edition and then the minimal Base edition, validating that the graphical installer, KDE session and core management tools operate as expected in a virtualised environment typical of many evaluation workflows.​

ObsidianOS is still a relatively young project and continues to evolve through its GitHub repositories, where issues, code and documentation are developed in the open. Users interested in the distribution’s internals, contribution guidelines or release cadence are encouraged to review the organisation’s repositories and associated wiki content to understand how components like the installer, overlays, control centre and supporting services fit together.​

The Distrowrite Project concludes that ObsidianOS represents a serious attempt to rethink how an Arch‑based desktop system can handle updates, rollback and experimentation by blending an A/B partitioning model, user‑space overlays and tightly integrated tooling into a cohesive platform rather than a simple re‑theme or repackaging of Arch.​

The names, logos and brands mentioned in this article, including “Arch Linux”, “Obsidian” and any other third‑party trade names or trademarks, are the property of their respective holders and are used here for identification purposes only; no endorsement is implied. The Distrowrite Project aims for accurate, fair and up‑to‑date coverage of open‑source software, but all technical details, features and behaviours may change over time, so readers should verify critical information against official ObsidianOS resources before acting on it and always use open‑source software responsibly, securely and in full compliance with applicable laws and licences.

References
– ObsidianOS GitHub organisation: https://github.com/Obsidian-OSgithub​
– ObsidianOS “Obsidian OS” meta‑repository: https://github.com/Obsidian-OSgithub​
– ObsidianOS files and installation entry point: https://files.obsidianos.xyz/obsidianos​
– Community announcement detailing features and editions: https://www.reddit.com/r/arch/comments/1niizj2/obsidianoss_big_new_features_user_mode_overlays/reddit​
– Third‑party technical review of ObsidianOS: https://itsfoss.com/obsidianos-review/itsfoss​

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