Linux kernel based OS
Kubuntu Linux is a user friendly operating system based on KDE, the K Desktop Environment. With a predictable 6 month release cycle and part of the Ubuntu project, Kubuntu is the GNU/Linux distribution for everyone. Improved desktop, updated applications and increased usability features are just a few of the surprises with this latest release.
Ubuntu Linux brings together the best of free and open source software delivered on a stable, easy to use and learn platform. Ubuntu claims to be always free of charge, including enterprise releases and security updates. It comes with full commercial support from Canonical and hundreds of companies around the world. Ubuntu includes the very best translations and accessibility infrastructure that the free software community has to offer.
Suse Linux is a worldwide community program sponsored by Novell that promotes the use of Linux everywhere. The program provides free and easy access to openSUSE. Here you can find and join a community of users and developers, who all have the same goal in mind — to create and distribute the world's most usable Linux. openSUSE also provides the base for Novell's award-winning SUSE Linux Enterprise products. The goals of openSUSE project are to make openSUSE the easiest Linux distribution for anyone to obtain and the most widely used open source platform. Provide an environment for open source collaboration that makes openSUSE the world's best Linux distribution for new and experienced Linux users.
Mandriva Linux is the best way to start using Linux. A full Linux operating system on a single CD for both new and experienced Linux users, it is fast to download and install, and also safe to try with a live mode. Requirements: any Intel or AMD processor, 1Ghz or better - dual-core supported, RAM - 256 MB minimum, 512 MB recommended.
Debian Linux is a free operating system (OS) for your computer. An operating system is the set of basic programs and utilities that make your computer run. Debian uses the Linux kernel (the core of an operating system), but most of the basic OS tools come from the GNU project; hence the name GNU/Linux. Debian will run on almost all personal computers, including most older models. Each new release of Debian generally supports a larger number of computer architectures. Almost all common hardware is supported.
Elive Linux is a complete operating system for your computer. It's the perfect choice for replacing your proprietary, high-cost system. It is built on top of Debian GNU/Linux and customized to meet your needs for a complete operating system while still offering the user eye-candy, with minimal hardware requirements. It will help to turn your old computer into a high-powered work-station again, with an Interface that dazzles everybody that sees it. Elive comes with a full suite of applications for your work and leisure time needs. It offers everything from a full Office suite to games and Multimedia. You can enjoy watching movies or listening to music. You can even make your own DVD movies with menus, music and it works. Elive gives you the ability to make 3D animations, or compose your own movies in a real-time non-linear video editor from simple videos taken with your video camera. You can edit and manipulate audio and image files for better quality, effects, or design. Elive is a very stable system that will continue to run day after day without problems. The Enlightenment desktop is ultra-fast and perfectly stable with no random errors or surprises. There are no viruses, trojans, spyware, adware, or any similar things. Elive is a secure and serious system.
Austrumi is a business card size (50MB) bootable Live CD Linux distribution. Imagine the ability to boot your favorite Linux distribution whether you are at home, at school or at work... Requirements: CPU - Intel-compatible (pentium2 or later); RAM - at least 128 MB (if 128 Mb or less, then run boot: al nocdcache).
Ubuntu Studio is aimed at the GNU/Linux audio, video and graphic enthusiast as well as professional. It provides a suite of the best open-source applications available for multimedia creation. Completely free to use, modify and redistribute. Your only limitation is your imagination.
JAD Studio is a Linux operating system. It comes with a comprehensive collection of free, open source multimedia software for audio visual content creation. JackLab was created for music production and so it comes with a real-time kernel optimised for low-latency recording, the latest music software such as Ardour and Rosegarden and over 300 plug-ins and effects. JAD gives you the option of using the lightweight yet beautiful looking Enlightenment 17 desktop environment which uses much less RAM than KDE does. JAD 1.0 is based upon OpenSUSE 10.2 and hence packages (programs, also known as binaries) for OS 10.2 should work under JAD 1.0 and vice versa.
Fedora Linux is a Linux-based operating system that showcases the latest in free and open source software. Fedora is always free for anyone to use, modify, and distribute. It is built by people across the globe who work together as a community: the Fedora Project. The Fedora Project is open and anyone is welcome to join.
Sabayon Linux is an advanced, scalable and community driven Linux distribution. It tries to provide its users the best and most complete computing experience. Sabayon Linux uses Gentoo Linux as its base. It is (and always will be) 100% compatible with it.
Mepis Linux allows you to test and try the software before you install to your harddrive. It includes the very best business and multimedia programs, and features unique hardware detection and configuration superior to any others. SimplyMEPIS is pre-configured for simplicity and ease of use, you're productive in a matter of minutes, not hours.
Pardus is a very simple Turkish operating system. Pardus comes with internet tools, office suite, multimedia (picture, music, video, etc) players, games and numerous applications populated in a single CD to answer needs of desktop users.
Slackware Linux is a complete 32-bit multitasking "UNIX-like" system. It's currently based around the 2.6 Linux kernel series and the GNU C Library version 2.3.4 (libc6). It contains an easy to use installation program, extensive online documentation, and a menu-driven package system. A full installation gives you the X Window System, C/C++ development environments, Perl, networking utilities, a mail server, a news server, a web server, an ftp server, the GNU Image Manipulation Program, Netscape Communicator, plus many more programs. Slackware Linux can run on 486 systems all the way up to the latest x86 machines (but uses -mcpu=i686 optimization for best performance on i686-class machines like the P3, P4, and Duron/Athlon).
Dynebolic Linux is shaped on the needs of media activists, artists and creatives as a practical tool for multimedia production: you can manipulate and broadcast both sound and video with tools to record, edit, encode and stream, having automatically recognized most device and peripherals: audio, video, TV, network cards, firewire, usb and more. You can employ this operating system without the need to install anything, and if you want to run it from harddisk you just need to copy a directory. It is optimized to run on slower computers, turning them into full media stations: the minimum you need is a pentium1 or k5 PC 64Mb RAM and IDE CD-ROM, or a modded XBOX game console - and if you have more than one, you can easily do clusters.
DreamLinux is a modern and modular Linux system that can be run directly from the CD and optionally be easily installed onto your HD. Dreamlinux comes with a selection of the best applications designed to meet mostly of your daily needs. It is based on Debian and Morphix, which means it takes advantages of their best features and adds its own modern development tools.
Geexbox Linux is a free embedded Linux distribution which aims at turning your computer into a so called HTPC (Home Theater PC) or Media Center. Being a standalone LiveCD-based distribution, it's a ready to boot operating system than works on any Pentium-class x86 computer or PowerPC Macintosh, implying no software requirement. You can even use it on a diskless computer, the whole system being loaded in RAM. The distribution comes with a complete and automatic hardware detection, not requiring any driver to be added. It supports playback of nearly any kind of audio/video and image files and all known codecs and containers are shipped in, allowing playing them through various physical supports, either being CD, DVD, HDD, LAN or Internet. GeeXboX also comes with a complete toolchain that allows developers adding easily extra packages and features but that might also be used to give birth to many dedicated embedded Linux systems.
XBox Linux can be a full desktop computer with mouse and keyboard, a web/email box connected to TV, a server or router or a node in a cluster. You can either dual-boot or use Linux only; in the latter case, you can replace both IDE devices. You can even connect the Xbox to a VGA monitor.
iQunix OS is a Linux operating system based on the popular Ubuntu distribution. It's unique design offers to Ubuntu users and specialist, a "bare-bone" GNOME based, operating system in which nothing is pre-installed.
BSD kernel based OS
Free BSD Unix is an advanced operating system for x86 compatible (including Pentium and Athlon), amd64 compatible (including Opteron, Athlon64, and EM64T), UltraSPARC, IA-64, PC-98 and ARM architectures. It is derived from BSD, the version of UNIX developed at the University of California, Berkeley. It is developed and maintained by a large team of individuals. FreeBSD offers advanced networking, performance, security and compatibility features today which are still missing in other operating systems, even some of the best commercial ones.
PC BSD Unix is a free operating system with ease of use in mind. Like any modern system, you can listen to your favorite music, watch your movies, work with office documents and install your favorite applications with a setup wizard at a click. It offers the stability and security that only a BSD-based operating system can bring, while as the same time providing a comfortable user experience, allowing you to get the most out of your computing time. With PC-BSD you can spend less time working to fix viruses or spyware and instead have the computer work for you.
DesktopBSD Unix aims at being a stable and powerful operating system for desktop users. It combines the stability of FreeBSD, the usability and functionality of KDE and the simplicity of specially developed software to provide a system that's easy to use and install. The DesktopBSD Tools are a collection of applications designed to make life easier and more productive. Even inexperienced users can perform administrative tasks such as configuring wireless networks, accessing USB storage devices and installing and upgrading software.
GNU-Darwin Linux aims to be the most free software distribution. It focuses on projects that leverage the unique combination of Darwin and GNU, and help users to enjoy the benefits of software freedom.
Update: Two More Open Source Systems: http://www.opensuse.org/en/ , https://www.gnome.org/ and http://zorin-os.com/
Another type OS
Haiku is an open-source operating system currently in development designed from the ground up for desktop computing. Inspired by the BeOS, Haiku aims to provide users of all levels with a personal computing experience that is simple yet powerful, and free of any unnecessary complexities. Haiku is developed mostly by volunteers around the world in their spare time.
AROS Research Operating System is a lightweight, efficient and flexible desktop operating system, designed to help you make the most of your computer. It's an independent, portable and free project, aiming at being compatible with AmigaOS 3.1 at the API level (like Wine, unlike UAE), while improving on it in many areas. The source code is available under an open source license, which allows anyone to freely improve upon it.
Menuet is an Operating System in development for the PC written entirely in 32/64 bit assembly language, and released under the License. It supports 32/64 bit x86 assembly programming for smaller, faster and less resource hungry applications. Menuet has no roots within UNIX or the POSIX standards, nor is it based on any particular operating system. The design goal has been to remove the extra layers between different parts of an OS, which normally complicate programming and create bugs.
Minux3 is a new open-source operating system designed to be highly reliable, flexible, and secure. It is loosely based somewhat on previous versions of MINIX, but is fundamentally different in many key ways. MINIX 3 adds the new goal of being usable as a serious system on resource-limited and embedded computers and for applications requiring high reliability.
Syllable is a reliable and easy-to-use open source operating system for the home and small office user. Syllable is still being developed, but it is already relatively stable and mature, including the following features: booting usually takes less than ten seconds, a full GUI is built into the OS; support for a wide range of common hardware devices, including video, network, and sound cards from manufacturers such as Intel, AMD, 3Com, nVidia, and Creative; Internet access through an Ethernet network (PPP and PPPoE are not fully supported yet, but are available in a test version); a graphical web browser, based on WebKit; an e-mail client (Whisper), and hundreds of other native applications; a journalled file system, modelled on the BeOS file system; and more.
E/OS is a open source emulator of the BeOS, Darwin, DOS, Linux, and Windows API on top of X, allowing run many unmodified programs to run on Linux, FreeBSD, Mac OS X, Solaris, Windows and DOS.
FreeVMS is an OpenVMS-like operating system which can run on several architectures like i386, PPC, Alpha, and many others. It consists of a POSIX kernel and a DCL command line interpreter. The only architectures currently supported are i386 and x86-64.
JNode is a simple to use & install Java operating system for personal use. It runs on modern devices.
BeleniX is an OpenSolaris Distribution with a Live CD (runs directly off the CD). It includes all the features of OpenSolaris and adds a whole variety of open source packages. It can be installed to harddisk as well. BeleniX is free to use, modify and distribute.
FreeDOS aims to be a complete, free, 100% MS-DOS compatible operating system. It is often used with emulators such as Bochs or Linux's dosemu, and it can also run standalone on PCs or embedded systems.
The GNU Hurd is the GNU project's replacement for the Unix kernel. The Hurd is a collection of servers that run on the Mach microkernel to implement file systems, network protocols, file access control, and other features that are implemented by the Unix kernel or similar kernels (such as Linux).
Plan 9 was born in the same lab where Unix began. Underneath, though, lies a new kind of system, organized around communication and naming rather than files and processes. In Plan 9, distributed computing is a central premise, not an evolutionary add-on. The system relies on a uniform protocol to refer to and communicate with objects, whether they be data or processes, and whether or not they live on the same machine or even similar machines. A single paradigm (writing to named places) unifies all kinds of control and interprocess signaling.
SharpOS is a community effort to write an operating system based on .NET technology, with a strong sense of security and manageability.
Learn More About Free Open Source Systems Here: http://www.linuxrelease.com/ and http://distrowatch.com/