Half-Rolling Release Model
From The Chakra Project
The half-rolling release model, based on Arch’s rolling release model, was created by the Chakra Project when Chakra was born. It aims to provide a stable core of software, and rolling applications on top of it, and it is one of the keys of the success of the distribution.
The Big Picture
In our release model, we define two different layers of software, each one with its own release model:
- The core layer consists of software that is critical for an operational system, such as the graphics or sound subsystems.
- This layer is not updated as soon as possible, but following a more tradicional time-based approach. Its software packages are updated following predefined schedules. Unlike the traditional release model, though, there isn’t a single schedule for all the packages: it is a loosely time-based release model on a group basis, where for different groups of packages there are different schedules.
- This ensures the system is always stable.
- The applications layer contains the rest of the software, including the applications users interact with.
- These packages are updated following an application-based rolling release model, where end-user applications are updated following the rolling release model, whereas their dependencies also roll but only as long as updating them does not prevent the end-user applications from running smoothly, or makes them loose functionality.
- That way you can always enjoy bleeding-edge application.
For the end-user, this release model provides a three-fold benefit:
- One-Time Installation
- You will only have to install your system once. You can then install any updates from the system itself thorugh the package manager. New Chakra ISOs are basically snapshots of the current state of things.
- Latest Software
- As your favorite applications mature and advance, you will always have access to their latest version. Chakra is often one of the first distributions to add the new updates to its repositories.
- Since the core software is not updated following a rolling release model, we have time to thoroughly test it before any upgrade.
The only thing that differs in our implementation from the big picture of the half-rolling release model is that our applications layer is KDE-centric — built around the KDE Software Compilation. That means, the layer is split in two, a layer with the KDE software and a layer with the rest of the software.
Hence, we have actually three layers:
- The packages in the core layer are available in the Core and Platform repositories.
- The desktop layer contains the KDE SC packages, available in the Desktop repository.
- Our applications layer contains software not developed by KDE, and their packages are available in the Apps, Bundles and Games repositories.
During updates, the desktop layers takes precedence over the applications layer. For example, when two packages, one from the desktop layer and one from the applications layer, share a dependency, the former package will dictate when can that dependency be updated.
- For technical implementation details, see the Chakra Release Model.
- In the sense that schedules are not strictly defined. For example, a group of packages can be updated twice a year, as opposed to every six months or every 180 days.
- Chakra News: Chakra 2011.04 (Aida) on a Linux-Magazine DVD.