Linux OS Based On: Understanding the Relationships
Understanding Linux Distributions and Their Relationships
During an evaluation of various Linux distributions, the statement "Ubuntu is based on Debian" is commonly encountered. However, the precise implications of this assertion are often unclear.
The Parent-Child Relationship Between Distributions
This relationship signifies that Ubuntu was initially constructed utilizing the software packages and foundational elements of Debian. Essentially, Ubuntu inherited a robust base from Debian.
It's important to understand that this isn't simply a case of copying code. Instead, Ubuntu leverages Debian’s infrastructure for core functionality.
How Debian Serves as a Foundation
Debian provides a vast repository of pre-compiled software, a package management system, and a set of core utilities. These components are crucial for the operation of any Linux distribution.
Ubuntu developers then build upon this foundation, adding their own customizations, desktop environments, and applications.
Key Differences and Divergence
While Ubuntu originates from Debian, it has evolved into a distinct distribution over time. Differences exist in areas like release cycles, default software selections, and the level of user support.
Ubuntu generally aims for a more user-friendly experience, with faster release cycles and a focus on ease of installation and use.
SuperUser as a Source of Information
This explanation originates from a question posed and answered on SuperUser, a valuable resource within the Stack Exchange network.
Stack Exchange is a collaborative platform comprised of numerous question-and-answer websites, fostering a community-driven approach to knowledge sharing.
SuperUser specifically focuses on expert answers related to computer systems and software, making it an ideal place to find clarification on technical topics like Linux distributions.
Understanding Linux Distributions and Their Relationships
A SuperUser user, PLPiper, recently inquired about the relationships between different Linux distributions. They noticed the frequent phrasing of one OS being "based on" another, and sought clarification.
The Core Concept: Layers of Development
The statement that one Linux OS is based on another doesn't imply a fundamental difference in the kernel. Instead, it refers to a layered approach to development and distribution.
Essentially, distributions build upon a foundation provided by another, adding their own unique features, tools, and desktop environments.
Examples Explained
Consider the examples provided by PLPiper:
- Fedora is built upon the codebase of Red Hat Enterprise Linux (RHEL).
- Ubuntu utilizes Debian as its base.
- Linux Mint, in turn, is derived from Ubuntu.
These relationships aren't arbitrary; they represent a lineage of development and shared infrastructure.
Why Not Just "Based on Linux?"
PLPiper's question – "Aren't they all based on Linux?" – is valid. All Linux distributions share the Linux kernel as their core.
However, the kernel alone doesn't constitute a complete operating system. Distributions add crucial components like system utilities, package managers, and graphical user interfaces.
The Role of Upstream and Downstream
The "based on" relationship can be understood through the concepts of "upstream" and "downstream."
The upstream distribution provides the foundation, while the downstream distribution builds upon it. For instance, Debian is upstream to Ubuntu, and Ubuntu is upstream to Linux Mint.
Benefits of This Approach
This layered approach offers several advantages:
- Reduced Development Effort: Distributions don't need to reinvent the wheel.
- Stability: Leveraging a well-established base provides a stable foundation.
- Community Support: Downstream distributions benefit from the upstream community.
It allows for specialization and innovation within the broader Linux ecosystem.
Analogies to Other Operating Systems
The "based on" concept is similar to the relationship between OS X and Darwin. Darwin is the open-source core of OS X, and Apple adds its proprietary features on top.
This model fosters a collaborative environment where different teams can contribute to the overall advancement of the operating system.
Understanding Linux and its Distributions
A SuperUser community member, kostix, provides a comprehensive explanation of the Linux ecosystem.
At its core, Linux is a kernel – a sophisticated software component that interfaces directly with computer hardware. It exposes an Application Programming Interface (API) and defines the Application Binary Interface (ABI), enabling "user-space" applications to function.
Operating Systems vs. Distributions
Distributions like Debian and RedHat are complete operating systems. They encompass the kernel alongside a suite of user-space programs designed to make a computer functional, handling tasks such as email, web browsing, and robotic control.
While these operating systems often share common software – limited options exist for mail servers or browsers, for example – they diverge in their implementation approaches, overarching goals, and release schedules.
The Role of "Distributions"
These operating systems are frequently referred to as "distributions." This terminology originates from the historical possibility of manually compiling and installing all necessary software. Distributions, therefore, distribute pre-packaged software, simplifying the installation process for users.
They also typically include installers to facilitate the setup of the operating system on a target machine.
Complexity of OS Development
Developing and maintaining an operating system is an exceptionally complex undertaking. It necessitates a robust infrastructure, including upload queues, build servers, bug tracking systems, archive servers, and mailing list software, alongside a dedicated team.
This complexity creates a significant barrier to entry for creating a new operating system from scratch. Debian, for instance, supports approximately 37,000 packages across five different hardware architectures, highlighting the substantial effort involved.
Building Upon Existing Foundations
Consequently, those seeking to create a new operating system often leverage existing foundations. This is where operating systems based on others emerge.
Ubuntu, for example, is built upon Debian, importing the majority of its packages and repackaging only a select few, alongside incorporating its own artwork, default settings, and documentation.
Variations in "Based On" Relationships
The relationship of being "based on" can vary. Debian actively supports the creation of "pure blends" – distributions that utilize Debian directly, adding packages and tools tailored to specific user groups, such as those in education, medicine, or the music industry.
It’s also important to note that not all of these operating systems are exclusively based on Linux. Debian also offers support for FreeBSD and Hurd kernels, although these have smaller user bases.
Further insights and discussion can be found in the original Stack Exchange thread here. Feel free to share your thoughts and additions in the comments section.