Clarifying that the file system is within the kernel for Linux

Author: fusion809

Linux/Linux-distros-comparison.md

@@ -63,7 +63,7 @@ When I mention "exotic" or "obscure" software, I mean software that is fairly un
 
 # Preliminaries
 ## What is Linux?
-A Linux distribution is defined by its use of the [Linux kernel](https://en.wikipedia.org/wiki/Linux_kernel). The kernel is the component of an operating system that manages all communication between hardware and software. [File system](https://en.wikipedia.org/wiki/File_system) (which provides a structure for the organization and access of files) support is also mostly within the kernel, although some tools for managing file systems (e.g. `mkfs` command) are provided by other core system software. Device drivers—which are pieces of software required to get specific hardware devices to work—are typically included within the kernel. That being said, support for certain file systems and devices is provided separately to the kernel due to licensing issues.
+A Linux distribution is defined by its use of the [Linux kernel](https://en.wikipedia.org/wiki/Linux_kernel). The kernel is the component of an operating system that manages all communication between hardware and software. On Linux, [file system](https://en.wikipedia.org/wiki/File_system) (which provides a structure for the organization and access of files) support is also mostly within the kernel, although some tools for managing file systems (e.g. `mkfs` command) are provided by other core system software. Device drivers—which are pieces of software required to get specific hardware devices to work—are typically included within the kernel. That being said, support for certain file systems and devices is provided separately to the kernel due to licensing issues.
 
 ## Licensing
 The Linux kernel is likely the single most popular operating system kernel in the world, due to its use in servers, Android smartphones and IoT devices. Unlike the kernel of Windows, it is [open source](https://en.wikipedia.org/wiki/Open_source). Open source, in this context, means that the source code of the Linux kernel is openly shared and can be legally modified and redistributed by anyone. The Linux kernel is licensed under the [GNU General Public License](https://en.wikipedia.org/wiki/GNU_General_Public_License) (GPL), which is [copyleft](https://en.wikipedia.org/wiki/Copyleft). A copyleft license is an open-source licence that requires that any code derived from code licensed under it is distributed under a similar copyleft license. Many companies (e.g. [NVIDIA](https://en.wikipedia.org/wiki/NVIDIA) and [Broadcom](https://en.wikipedia.org/wiki/Broadcom)) that design hardware and their device drivers choose not to distribute their drivers under the GPL or licenses compatible with it. Due to this, these drivers cannot be included in the kernel. This is one reason why desktop Linux users often experience hardware compatibility issues when running Linux. Likewise, the Linux kernel module that adds support for the [ZFS](https://en.wikipedia.org/wiki/ZFS) file system is distributed under the [Common Development and Distribution License](https://en.wikipedia.org/wiki/Common_Development_and_Distribution_License) (CDDL), which does satisfy the open-source criterion, but it is not copyleft and hence is not GPL compatible and cannot be included in the kernel.