Are Unix clones also Unix?


Another issue that gets into an almost endless debate is whether Linux is really a Unix because it is a clone. I collected some information on some sites so that we can study and analyze the subject to draw the real conclusion.

Many argue that Linux is not a Unix because it is a clone; even defend that BSDs are more Unix than Linux simply because their code base originated from the original Unix from AT&T and Bell Labs, however, if we take into account the process faced by the BSD community and the biggest claim by the community is that BSD had already been so modified that BSD no longer had the original Unix code, so how can we say that BSD is more Unix than Linux? What makes one operating system more Unix than the other? Have Unix derivation come from AT&T?

Likewise, if we consider the process facing Linux when the SCO accused IBM of breach of contract with code written for UnixWare and donating it to Linux (ie code from an original Unix running easily on Linux); so there is no way to claim that Linux is not a Unix. The most interesting thing is if we consider so many Linux programs ported to BSDs.

Three factors we have to consider is that, as described on the kernel.org page at about, they claim that Linux is a clone of Unix. It follows the POSIX specification and SUS (not from our public hospital service but from the Sigle UNIX Specification).

Linux is a clone of the Unix operating system, written from scratch by Linus Torvalds with the assistance of an elastic team of hackers around the Net. It is intended for compliance with the POSIX and Single UNIX Specification.

It has all the features you would expect in a fully developed modern Unix including real multitasking, virtual memory, shared libraries, on-demand loading, shared copy-on-write executables, proper memory management and multitasking network including IPv4 and IPv6.

According to the website opengroup.org on Unix, Single UNIX Specification provides a level of openness where those without the standard cannot, ensuring cross-platform compatibility and that the focus is on open standards for operating systems that include UNIX®, POSIX®, open source operating systems such as Linux® and BSD, real-time systems and computer networks.

The second thing is that Linux is not the only Unix clone. In this video I make a comparative analysis between three other operating systems being Minix, Xinu and Coherent to introduce other Unix clones and reach the real conclusion.

And the third and final factor is that Unix is ​​a family of operating systems and not a single operating system, as they follow the same patterns in the paragraphs mentioned above (this is what defines what Unix is ​​and what it is not). The biggest difference between UNIX clones or UNIX-Like operating systems for the original UNIX is not being able to load the UNIX name for being a registered trademark.

But if none of this is enough for you and in your opinion we are just pulling sardines for Linux, then we stop here with the link of the open group itself that mention that recently a Linux distribution has become UNIX certified continuing the trend and value of basing the operating system on the UNIX standard. I think that kills the whole bunch, doesn’t it? ?

Both Linux and BSDs are Unix operating systems, both belong to the same family and follow the same standards. Both keep this beauty alive and add more value to technology. What we need to analyze are technical aspects of both and all other Unix, advantages and disadvantages (there are many things that Linux has become even better than other Unix and the original Unix itself).

For now it’s just and until the next article.