Welcome!

Linux Containers Authors: Elizabeth White, Pat Romanski, Liz McMillan, Yeshim Deniz, Zakia Bouachraoui

Related Topics: Linux Containers

Linux Containers: Article

Linux.SYS-CON.com Exclusive: A Whirlwind Tour Of Open-Source Operating Systems

Some Are Famous, Some Lesser Known

The enormous success of GNU/Linux as an operating system and as an open source project has captured the imagination of developers, IT staffers, business people, journalists, educators, and even politicians. Linux is so visible, its brand and allure so strong, that most people forget or never notice the existence of an array of other open source OSes. Some of these platforms "compete" with Linux for market share and popular attention (like BSD and OpenSolaris), some complement Linux with additional capabilities or virtualize aspects of its operation (like RTLinuxFree and T-Kernel), while others target embedded or vertical applications (like eCOS and RTEMS) with a minimum of overlap with our TuxOS.

This article offers readers a survey of open source operating systems, some famous, some lesser known. Please pardon me if I have omitted your favorite free kernel or cherished RTOS. In fact, I'm always eager to be educated, so e-mail me with additions or corrections so I can build my list of legacy or lesser-known OSes, kernels, and executives.

BSD
The venerable Berkeley Software Distribution side of the Unix family is split into four branches - OpenBSD, NetBSD, FreeBSD, and BSD/OS. The three open branches continue in active development and broad deployment: NetBSD, OpenBSD, and FreeBSD, and today power many Web servers and even embedded applications (primarily networking). The fourth, BSD/OS, a commercial, semi-proprietary offshoot, met its demise when Wind River Systems (of VxWorks fame) acquired BSDi and subsequently brought its Unix product line to end-of-life.

BSD-family Unix OSes enjoy good reputations for performance and security, but for various reasons don't enjoy the large ubiquitous developer communities that Linux does. BSD OSes have been ported to a vast array of 16, 32, and 64-bit platforms, with the number of NetBSD ports rivaling Linux and also TRON for the title of "most ported." BSD Unixes also form the basis for a series of further-derived OSes, like Juniper Networks JUNOS and the Mac OS X. The Berkeley networking stack, most commonly BSDlite 4.4, also forms the basis for a large portion of TCP/IP networking functionality in other OSes, and strongly influences the Linux IP stack.

BSD is licensed under the BSD Copyright (license), which has recently gained the OS family new adherents among GPL-averse commercial interests. To learn more about BSD operating systems, visit www.bsd.org, a site that will also direct you to the homes of each BSD variant.

Darwin
Most users of Apple OS X probably don't know that their beloved Macintosh operating system is based on BSD 4.4 and Mach 3.0. Those who do recognize BSD at the heart of OS X and who venture to open shells and use the rich Unix command set and capabilities may not realize that Darwin is an open project of its own, and that they can contribute to its development and debugging. Learn about the Darwin project at http://developer.apple.com/darwin/.

eCOS
This open source real-time OS originated at Cygnus Software and today is part of the corpus of software under the Red Hat banner. eCOS offers a variety of scheduling options and IPC services and boasts POSIX APIs. eCOS supports a wide range of CPUs of both the embedded (PowerPC, ARM, MIPS, etc.) and enterprise variety (IA-32, x86). eCOS sits at the heart of the RedBoot monitor, so you may very well have used eCOS to boot Linux or another OS on an Intel XScale or other embedded system board without knowing it. Red Hat no longer supports eCOS as a product, which is maintained as a community project and licensed under a "GPL-compatible Free Software License," derived from the GPL with an explicit exception for static linking of user programs to the eCOS kernel. The eCOS copyright is in the process of being transferred to the Free Software Foundation. Visit http://sources.redhat.com/ecos/ for more information.

GNU Hurd
Richard Stallman's original GNU project had as its goal the creation of a 100% free Unix operating system replacement. In the early 1990s, the GNU system was almost complete, lacking only a kernel. The GNU Hurd was going to be a collection of server processes running on top of the Mach microkernel, which at the time was not a piece of free software. Before a free Mach kernel actually appeared, the Linux kernel came onto the scene, and began its ascent from a small open source project to its current strong and ubiquitous market position. Today, the GNU/Linux operating system incorporates most of the GNU system intended to work with Hurd, and gives the Linux kernel its familiar shells, utilities, and development tools. Find out more about the GNU system, Hurd (a.k.a. Alix), at www.gnu.org/gnu/thegnuproject.html.

ITRON and µITRON
TRON (The Real-time Os Nucleus) embedded RTOSes form a corpus of software that stems from the work of Dr. Ken Sakamura of Tokyo University in Japan. Since its inception almost two decades ago, the ITRON specification has been adopted by many leading Japanese semiconductor suppliers and device OEMs, and has been implemented for a range of processors and found a diverse application set. The µITRON kernel, in particular, continues to power single-chip low-end MCUs that otherwise could not use an OS due to the memory and execution speed constraints.

ITRON is not an open source OS per se - it's a shared operating system specification with a very large number of implementations (including open source versions) for a range of microprocessors, including familiar embedded CPUs like Motorola 68000 and PowerPC, ARM, and MIPS, as well as Japanese market-focused silicon like Fujitsu SPARClite, Hitachi H8300, H8/500 and SuperH, Mitsubishi M32 and 7700, NEC 78K, and legacy TRON processors. Even with strong competition from embedded Linux and RTOSes like VxWorks, ITRON platforms have held a dominant position in the Japanese market for over a decade. To learn more about ITRON, visit www.sakamura-lab.org/TRON/ITRON/home-e.html and www.tron.org/index-e.html.

As successors to TRON, T-Kernel and T-Engine together form an open RTOS definition and development environment. T-Engine Project standardizes and abstracts hardware interfaces and T-Kernel provides the definition of a TRON-compatible RTOS. T-Kernel architecture is designed to be virtual, with a goal of running other middleware (e.g., T-Java) and OSes (T-Linux and even Microsoft Windows) above it. To learn more, visit www.t-engine.org.

Mach
The Mach kernel and operating system got its start in the mid 1980s as a prototypical microkernel - that is, a collection of "pico-servers" that provide services to each other and to user applications. Mach grew to include interprocess communication among kernel-level services and for the rest of the system. It also accrued virtual memory support in the kernel and for user-level servers. Later, Mach saw the addition of lightweight kernel threads, multiprocessing, and support for Unix-style APIs.

The Mach kernel also formed the basis for a number of other OSes, including GNU Hurd, Mk-Linux, Macintosh MachTen, NeXT OS, Omron Luna, DEC OSF/1 for DEC Alpha, and IBM's OS/2 for RS6000 machines. While variously proprietary in its earlier instantiations, Mach is now an open source OS under the auspices of the Open Software Foundation. To learn more about Mach, visit the CMU Mach home page at www-2.cs.cmu.edu/afs/cs/project/mach/public/www/mach.html and the Mach4 page at the University of Utah at www.cs.utah.edu/flux/mach4/html/Mach4-proj.html. Linux on Macintosh enthusiasts should check out www.mach-linux.org.

More Stories By Bill Weinberg

Bill Weinberg brings over 18 years embedded and open systems experience
to his role as Open Source Architecture Specialist and Linux Evangelist
at the Open Source Development Labs, where he supports initiatives for
meeting developer and end-user requirements for Carrier-Grade, Data
Center and Desktop Linux.

Prior to the OSDL, Bill was a founding team-member at MontaVista
Software, and helped establish Linux as a favored platform for next-
generation intelligent embedded device development. In the course of
his career, Bill also worked at Lynx Real-Time Systems, Acer Computer,
and Microtec Research.

Today Bill is known for his writing and speaking on topics that include
Linux business issues, Open Source licensing, embedded application
porting/migration, and handheld applications. He pens columns in
LinuxUser and Developer, and Embedded Computing Design, and is a
contributor to periodicals like E.E.Times, Linux Journal and Elektronik.
Bill is also a featured speaker at conferences like Linux World, Real-
time Computing, and Embedded Systems.

More info at http://www.linuxpundit.com

Comments (6) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
Arioch 08/08/05 04:23:32 PM EDT

Guess such an overview would be great to see on WikiPedia.org !

What about LiveCD's ?
In Linux LiveCD usually is a sub-part of a distro, except for Knoppix, which is separate.
I've heard about FreeBSD-based LiveCD, but i do not know if it is separate distro.
Anyway - LiveCD concept is quite unusual IMHO to users of Win or MacOS :-)

Erghmmm, now at last why i came here. I think, You've forgotten one more BSD distro: DragonFly BSD :-)

And what about phones and PDAs? EPOC, Symbian?

Thanks!

Charles Forsyth 07/19/05 11:58:20 AM EDT

I was happy Inferno (and Plan 9) were mentioned, but should point out that Inferno is properly Free/Open software. The dual-licence scheme does not restrict its use to non-commercial use. If, as with Linux and the others, you keep to the terms of its GPL/LGPL/BSD set of licences, there is no need to get a commercial licence. That is only needed by those who wish to keep their changes proprietary. If they'd be happy using Linux under its terms, they don't need a commercial licence for Inferno. I think our having our own Free software licence led to that confusion, so several months ago we changed to use existing Free licences instead.

Charles Forsyth 07/19/05 11:57:53 AM EDT

I was happy Inferno (and Plan 9) were mentioned, but should point out that Inferno is properly Free/Open software. The dual-licence scheme does not restrict its use to non-commercial use. If, as with Linux and the others, you keep to the terms of its GPL/LGPL/BSD set of licences, there is no need to get a commercial licence. That is only needed by those who wish to keep their changes proprietary. If they'd be happy using Linux under its terms, they don't need a commercial licence for Inferno. I think our having our own Free software licence led to that confusion, so several months ago we changed to use existing Free licences instead.

Charles Forsyth 07/19/05 11:53:26 AM EDT

I was happy Inferno (and Plan 9) were mentioned, but should point out that Inferno is properly Free/Open software. The dual-licence scheme does not restrict its use to non-commercial use. If, as with Linux and the others, you keep to the terms of its GPL/LGPL/BSD set of licences, there is no need to get a commercial licence. That is only needed by those who wish to keep their changes proprietary. If they'd be happy using Linux under its terms, they don't need a commercial licence for Inferno. I think our having our own Free software licence led to that confusion, so several months ago we changed to use existing Free licences instead.

Mohit Sindhwani 07/17/05 09:31:35 PM EDT

Hi - it's a nice summary!! Thanks for putting it all in one place :)

Just wanted to add 1 point. While ITRON was not open source (though an opper source version, TOPPERS/JSP, was available), the T-Kernel *is* open source, though not licensed under GPL. However, the membership model of the T-Engine Forum means that higher level memmbers get access to the open source earlier than the general public. The money collected through the membership of a large number of rich corporations (approx 450 at the time of writing) is what drives the research and standardisation activities of the T-Engine Forum.

Cheers
mo.

There is some more information about the T-Engine in English on my website at http://www.onghu.com/te/

LinuxWorld News Desk 07/17/05 01:29:35 PM EDT

LinuxWorld Exclusive: A Whirlwind Tour Of Open Source Operating Systems
The enormous success of GNU/Linux as an operating system and as an open source project has captured the imagination of developers, IT staffers, business people, journalists, educators, and even politicians. Linux is so visible, its brand and allure so strong, that most people forget or never notice the existence of an array of other open source OSes.

IoT & Smart Cities Stories
SYS-CON Events announced today that DatacenterDynamics has been named “Media Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY. DatacenterDynamics is a brand of DCD Group, a global B2B media and publishing company that develops products to help senior professionals in the world's most ICT dependent organizations make risk-based infrastructure and capacity decisions.
CloudEXPO New York 2018, colocated with DXWorldEXPO New York 2018 will be held November 11-13, 2018, in New York City and will bring together Cloud Computing, FinTech and Blockchain, Digital Transformation, Big Data, Internet of Things, DevOps, AI, Machine Learning and WebRTC to one location.
@DevOpsSummit at Cloud Expo, taking place November 12-13 in New York City, NY, is co-located with 22nd international CloudEXPO | first international DXWorldEXPO and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time t...
DXWordEXPO New York 2018, colocated with CloudEXPO New York 2018 will be held November 11-13, 2018, in New York City and will bring together Cloud Computing, FinTech and Blockchain, Digital Transformation, Big Data, Internet of Things, DevOps, AI, Machine Learning and WebRTC to one location.
Cloud-enabled transformation has evolved from cost saving measure to business innovation strategy -- one that combines the cloud with cognitive capabilities to drive market disruption. Learn how you can achieve the insight and agility you need to gain a competitive advantage. Industry-acclaimed CTO and cloud expert, Shankar Kalyana presents. Only the most exceptional IBMers are appointed with the rare distinction of IBM Fellow, the highest technical honor in the company. Shankar has also receive...
A valuable conference experience generates new contacts, sales leads, potential strategic partners and potential investors; helps gather competitive intelligence and even provides inspiration for new products and services. Conference Guru works with conference organizers to pass great deals to great conferences, helping you discover new conferences and increase your return on investment.
Headquartered in Plainsboro, NJ, Synametrics Technologies has provided IT professionals and computer systems developers since 1997. Based on the success of their initial product offerings (WinSQL and DeltaCopy), the company continues to create and hone innovative products that help its customers get more from their computer applications, databases and infrastructure. To date, over one million users around the world have chosen Synametrics solutions to help power their accelerated business or per...
DXWorldEXPO LLC announced today that ICOHOLDER named "Media Sponsor" of Miami Blockchain Event by FinTechEXPO. ICOHOLDER gives detailed information and help the community to invest in the trusty projects. Miami Blockchain Event by FinTechEXPO has opened its Call for Papers. The two-day event will present 20 top Blockchain experts. All speaking inquiries which covers the following information can be submitted by email to [email protected] Miami Blockchain Event by FinTechEXPOalso offers sp...
SYS-CON Events announced today that IoT Global Network has been named “Media Sponsor” of SYS-CON's @ThingsExpo, which will take place on June 6–8, 2017, at the Javits Center in New York City, NY. The IoT Global Network is a platform where you can connect with industry experts and network across the IoT community to build the successful IoT business of the future.
IoT is rapidly becoming mainstream as more and more investments are made into the platforms and technology. As this movement continues to expand and gain momentum it creates a massive wall of noise that can be difficult to sift through. Unfortunately, this inevitably makes IoT less approachable for people to get started with and can hamper efforts to integrate this key technology into your own portfolio. There are so many connected products already in place today with many hundreds more on the h...