While many are familiar with operating systems such as Windows and Macintosh (Mac), not everyone has heard of Ubuntu. Ubuntu is a Debian-based Linux OS that can be installed on PCs, tablets, smartphones, and even your Raspberry Pi.
The cool thing about Ubuntu is that it is was developed around free software. Yes, that's right—you're not going to have to spend hundreds on an OS. This one is completely free.
The creative developers over at Ubuntu have coded a version for the Raspberry Pi 2 called Ubuntu MATE. This OS comes with LibreOffice, a free open-source suite that comprises programs for word processing, spreadsheets, slideshows, diagrams and drawings, working with databases, and composing mathematical formulae. Oh, and it's also offered in 110 languages.
This version of Ubuntu utilizes the MATE desktop environment, which includes a file manager that allows you to connect to your local and networked files. Along with the LibreOffice and file manager, MATE also includes a calculator, system monitor, and terminal. Ubuntu MATE is very intuitive and an attractive desktop environment that feels very traditional if you're familiar with Microsoft Windows or Apple Mac OS.
Image courtesy of Ubuntu
If you're a gamer, want to browse the web, or want to stream media in your house, you're in luck; Ubuntu MATE includes Mozilla Firefox, VLC, and you can download Steam for your gaming necessities.
RISC OS (ROOL)
Unlike Ubuntu, RISC OS Open Limited (ROOL) is not based on Linux but instead a completely different OS. RISC OS was created by Acorn Computers Ltd in Cambridge, England in 1987. While the Raspberry Pi didn't make its debut until 2012, RISC was designed to operate on the ARM chipset. Interestingly enough, Acorn Computers concurrently developed the Advanced RISC Machines (ARM) to integrate into their new line of Archimedes PCs.
RISC stands for "reduced instruction set computing", a design that provided higher performance when combined with a microprocessor capable of executing instructions using fewer cycles per instruction.
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Along with being free, RISC is a full desktop OS where the core environment includes a windowing system as well as a few apps all inside of 6MB. Being this small, it is also much simpler than modern a OS such as Linux.
While RISC OS hasn't been releasing new versions as frequently as Windows or Mac OS has been, this only means that there are fewer layers between you and the system. As it was once a closed-source OS, there is a ton of documentation in a series of books called the Programmers' Reference Manuals (PRM) which is kindly placed on the RISC OS.
Arch Linux is a lightweight and flexible OS that tries to keep it as simple as possible. As of now, the OS packages are optimized for i686 and x86-64 architectures. The company literally follows the KISS principle ("keep it simple, stupid") and tries to focus on elegance, proper code, and a minimalistic and simplistic environment.
It is claimed to be one of the best Linux distributions you can use, especially given that the level of customization you can achieve with Arch Linux is unlike other Linux iterations. You could use everything on open-source software or, if you want to go down the "make it work" route, NVIDIA drivers can be used as well. If you want to change your interface, there are plenty to choose from such as GNOME, Xfce, or even Cinnamon desktop environments.
Image courtesy of Erik Dubois
Many other GNU/Liux distributions tend to be more user-friendly, while Arch is more user-centric.
Pidora is another Linux distribution similar to Raspbian, but it is based on the Fedora distribution. It's slightly different in a few ways. First, it comes with a lot of different software than Raspbian, such as text editors programming environments, and more.
A really cool feature of Pidora is that it comes with a "headless mode" which allows the user to operate the Raspberry Pi without a keyboard or display monitor. If you have a speaker plugged in, it will also announce the IP address information back to the end-user. Just like other Linux distributions, Pidora has a ton of additional software and documentation over at the Fedora repository.
Image courtesy of Mic's Linux Experience
OpenELEC (Open Embedded Linux Entertainment Center)
OpenELEC (Open Embedded Linux Entertainment Center) is an embedded OS that was built around Kodi, an open-source entertainment media environment. The nice thing about OpenELEC is that they provide the "just enough operating system" principle. This allows it to consume very few resources and gives it a quick boot time from flash memory.
The designers wanted the OS to be lightweight while allowing support for Intel's HD Graphics, NVIDIA's GeForce and ION platform, AMD's Radeon and Fusion platform, as well as Broadcom's Crystal HD chip.
The great thing about this OS is that it supports a very wide variety of GPUs, making it possible to convert not-so-new computers into full-fledged home theater systems.
Do you have other alternatives you think belong on this list? Let us know in the comments!