Linc's list of Free Unix

Linux

Supported Platforms include Intel, Macintosh, Atari, Amiga and Sparc among many others. Support for other platforms like HP servers, Vaxes, Decstations, etc are currently being worked on.

Linux is an operating system that was initially created as a hobby by a young student, Linus Torvalds, at the University of Helsinki in Finland. Linus had an interest in Minix, a small UNIX system, and decided to develop a system that exceeded the Minix standards. He began his work in 1991 when he released version 0.02 and worked steadily until 1994 when version 1.0 of the Linux Kernel was released.
Linux is developed under the GNU General Public License and its source code is freely available to everyone. This however, doesn't mean that Linux and its assorted distributions are free -- companies and developers may charge money for it as long as the source code remains available. Linux may be used for a wide variety of purposes including networking, software development, and as an end-user platform. Linux is often considered an excellent, low-cost alternative to other more expensive operating systems.

For more info see http://www.linux.org.

Minix

Supported Platforms are Intel, Macintosh, Atari, Amiga and Sparc.

MINIX is a free UNIX clone that is available with all the source code. Due to its small size, microkernel-based design, and ample documentation, it is well suited to people who want to run a UNIX-like system on their personal computer and learn about how such systems work inside. It is quite feasible for a person unfamiliar with operating system internals to understand nearly the entire system with a few months of use and study. MINIX has been written from scratch, and therefore does not contain any AT&T code--not in the kernel, the compiler, the utilities, or the libraries. For this reason the complete source can be made available (by FTP or via the WWW).

For more info see http://www.minix.org.

FreeBSD

Supported platforms are Intel compatible (x86), DEC Alpha, and PC-98, and additional platforms are in various stages of development.

FreeBSD is based on the 4.4BSD-Lite release from Computer Systems Research Group (CSRG) at the University of California at Berkeley, and carries on the distinguished tradition of BSD systems development. In addition to the fine work provided by CSRG, the FreeBSD Project has put in many thousands of hours in fine tuning the system for maximum performance and reliability in real-life load situations. As many of the commercial giants struggle to field PC operating systems with such features, performance and reliability, FreeBSD can offer them now!
The applications to which FreeBSD can be put are truly limited only by your own imagination. From software development to factory automation, inventory control to azimuth correction of remote satellite antennae; if it can be done with a commercial UNIX product then it is more than likely that you can do it with FreeBSD, too! FreeBSD also benefits significantly from the literally thousands of high quality applications developed by research centers and universities around the world, often available at little to no cost. Commercial applications are also available and appearing in greater numbers every day.

For more info see http://www.freebsd.org.

NetBSD

Supported platforms include algor, alpha, amiga, arc, arm26, arm32, ari, bebox, cats, cobalt, dreamcast, evbsh3, hp300, hpcarm, hpcmips, i386, luna68k, mac68k, macppc, mipsco, mmeye, mvme68k, netwinder,newsmips, next68k, ofppc, pc532, pmax, prep, sandpoint, sgimips, sparc, sparc64, sun2, sun3, vax, x68k, and there are probably some I missed. If a particular port is *not* listed here you can bet I either missed it or it is currently being worked on.

NetBSD is a free, secure, and highly portable UNIX-like operating system available for many platforms, from 64-bit AlphaServers and desktop systems to handheld and embedded devices. Its clean design and advanced features make it excellent in both production and research environments, and it is user-supported with complete source. Many applications are easily available.

For more info see http://www.netbsd.org.

OpenBSD

Supported platforms include alpha, Amiga, hp300, i386, mac68k, mvme68k, pmax, powerpc, sparc, Sun3, and vax.

The OpenBSD project produces a FREE, multi-platform 4.4BSD-based UNIX-like operating system. Our efforts emphasize portability, standardization, correctness, proactive security and integrated cryptography. OpenBSD supports binary emulation of most programs from SVR4 (Solaris), FreeBSD, Linux, BSD/OS, SunOS and HP-UX.

For more info see http://www.openbsd.org.

GNU Hurd

Supported platform is intel.

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).
Currently, the Hurd runs on IA32 machines. The Hurd should, and probably will, be ported to other hardware architectures or other microkernels in the future.
The Hurd is part of the GNU, which is a complete free operating system. Since the Hurd is not in production use yet, the version of GNU that is popular today is GNU/Linux, which uses Linux as the kernel instead of the Hurd.

For more info see http://www.gnu.ai.mit.edu/software/hurd/hurd.html.

QNX RTP (Real Time Platform)

Supported platform is intel.

The QNX realtime platform is built on the QNX Neutrino realtime OS, the most advanced RTOS on the market. The QNX Neutrino RTOS enables the design of highly reliable, scalable, and deterministic systems. The microkernel includes only a small set of core services within the kernel, including thread services, message passing, mutexes, condition variables, semaphores, signals, and scheduling. The kernel can be extended by dynamically plugging in service-providing processes, such as file systems, networking, POSIX message queues, and device drivers. With features like multitasking, threads, priority-driven preemptive scheduling, synchronization, and fast context switching (0.55 ľsec on a Pentium III), the RTOS provides the serious realtime performance. Our full implementation of the TCP/IP protocol suite and utilities - including PPP, DHCP, NFS, RPC, and SNMP - makes it possible to run a variety of Internet services over a wide choice of networks. Using Ethernet or serial lines, users can connect to the Internet, the company WAN, log in to remote systems, exchange mail, run remote user interfaces, and more.

For more info see http://get.qnx.com.

Plan9

Supported platform is Intel x86 & multiprocessors. Also, although the sources are available for other architectures, the binaries and libraries are built only for the Intel x86 architectures. Kernel source is available for x86, Mips, DEC Alpha, and Power PC architectures. Compilers also exist for AMD 29000, Motorola MC68000 and MC68020, Intel i960, and SPARC. (Unlike the the last release, no SPARC kernel exists for the current system.) The compilers and related tools have been made easier to port to Unix and Windows.

Plan 9 began in the late 1980's as an attempt to have it both ways: to build a system that was centrally administered and cost-effective using cheap modern microcomputers as its computing elements. The idea was to build a time-sharing system out of workstations, but in a novel way. Different computers would handle different tasks: small, cheap machines in people's offices would serve as terminals providing access to large, central, shared resources such as computing servers and file servers. For the central machines, the coming wave of shared-memory multiprocessors seemed obvious candidates. The philosophy is much like that of the Cambridge Distributed System [NeHe82]. The early catch phrase was to build a UNIX out of a lot of little systems, not a system out of a lot of little UNIXes.
The third release of the Plan 9 operating system from Bell Labs is something of a snapshot of the current system. This differs from the previous, 1995 release, which was a more coordinated, well-defined release of an already-out-of-date system. Also, the previous releases were distributed on fixed media, while this release is being done over the web. The other major difference is that the third release is licensed under an open source agreement, which we hope will encourage people to experiment with it. Beyond that, there are innumerable little changes throughout the code. Although superficially it is the same environment, there is hardly an aspect of the system that has not been redesigned, rewritten, or replaced.

For more info see http://cm.bell-labs.com/plan9dist/.

Solaris

Supported platforms are Sun machines, and Intel.

Now you can use the Solaris[tm] 8 Operating Environment at home or at work -- without paying a license fee. For only the cost of media ($75 U.S.) plus shipping, you can use the software on an unlimited number of computers with a capacity of eight or fewer CPUs. FREE downloads are also available.
The Solaris 8 Operating Environment is the established OS leader for availability, scalability, and security in the Internet age. In Solaris 8 software, Sun delivers a trustworthy, universal platform to meet the needs of dot-com businesses -- from small startups to large Fortune 1000 enterprises. It's no surprise that the Solaris Operating Environment is the leading UNIXŽ environment today. Solaris software was originally designed with the Internet in mind. TCP/IP, the central Internet protocol, has been at the core of Solaris networking for more than 15 years. Through its time-tested design -- a small, stable kernel, modular and extensible components, and well-defined interfaces -- the Solaris platform delivers rock-solid stability and predictability for business-critical applications.

For more info see http://www.sun.com/software/solaris/binaries/.

SCO Unix

Supported platform is Intel.

Openserver 5.0.6

Here's what SCO has to say about their Openserver Unix OS...
SCO OpenServer systems have been the de facto operating system platform for small and medium sized businesses for over a decade. With the latest generation of SCO OpenServer systems, you can easily expand your computing environment as your business computing needs grow. Integrated support for electronic mail and Internet services ensures that your business can leverage the World-Wide-Web to give your company the exposure it deserves and communicate more efficiently with customers and prospects. Built-in support for Windows File/Print services means that a single multi-functional server platform can be utilized to run your entire operation, while the field-proven reliability of SCO OpenServer keeps you in business.

Unixware 7

Here's what SCO has to say about their Unixware Unix OS...
With the latest SCOŽ UNIX operating system - UnixWareŽ 7 - delivers a new level of power, value and versatility to support the complete range of customers, from the small business through the high-end data center. With UnixWare 7, IT professionals no longer have to rely on proprietary RISC-based UNIX systems to build the reliable, scaleable and high-performance business solutions they demand. UnixWare 7 delivers it all - enterprise UNIX system power, reliability and scalability with the economics and value of standard Intel processor-based systems for all computing environments.

Generally speaking, the difference between the two is a System 5 type set up as opposed to a BSD type set up. Anyhow, the Unix Giant that SCO is finally decided to give away free *SINGLE* user licenses for their OS, however, you must pay for the media ($25-$50):

You can use (your free license) for learning about UNIXŽ systems, developing software that you do not sell, personal computing, or to run a personal web site. It can also be used for open source development and speculative development (Product development done before a product is shipped).You may not use it in your business or to support commercial or profit-making activities.

For more info see http://www.sco.com/offers/.

Conclusion

There are many many free *unix like* operating systems floating around out there and most if not all of them can be found quickly with a simple internet search. The OS's I have listed above are, in my opinion, the best. They are also all available to use for free unlike most of the others. Unix is a fine and robust operating system, and although as a LUG our mainstay is Linux, it can be quite helpful being versed in some other Unices, and since the ones I listed are *free* to use they fit in well to an extent with the Linux ideology. Give them a try - Unix is fun!

-Linc