Linux has many distros. Does that happen with UNIX too? thanks

Quote: Original post by Skoron
Linux has many distros.
Does that happen with UNIX too?

thanks

Worse. Most Linux distros run more-or-less the same kernel with more-or-less the same filesystem layout and the same C library, so stuff can be made to work on pretty much any Linux distro.

Unix, however, is not really an operating system anymore. It's just an idea, with many implementations - the *BSDs, Linux, Solaris, AIX, SCO UnixWare, HP-UX, MacOS, QNX, etc. Most of which are incompatible.

This should give an idea of how fragmented Unix is.

Wikipedia: Unix™, and Single Unix Specification.

Thanks guyz :)

So if i get it, Linux, Solaris, MacOS and others evolved from UNIX, which was at first an operating system, but now it is not used anymore because the evolved OSes are better now, right?

But why all those OSes are incompatible?, while they evolved form the same OS

thanks

Quote: Original post by Skoron
So if i get it, Linux, Solaris, MacOS and others evolved from UNIX, which was at first an operating system, but now it is not used anymore because the evolved OSes are better now, right?

Wrong.

UNIX is a standard, a specification, which means that many different concrete operating systems (AIX, HP-UX, even XENIX) can be developed and marketed that fully comply with that standard. Some of them are very much still in use today, because of UNIX' long history in the industrial place. Linux is no match for AIX, for instance, though IBM has made Linux a primary guest OS.

(Per explanation, AIX runs on machines that typically have 16 processors and up, using a virtualization system that allows it to run copies of itself or other operating systems within the same "machine" concurrently. These other OSes are called guests, while the main AIX installation is the host.)

Quote: But why all those OSes are incompatible?, while they evolved form the same OS.

Because no one operating system meets everyone's needs. Consequently, in large part made possible by the source code for UNIX being readily available, various customizations and modifications were made.

That said, it's not entirely accurate to say that all those OSes evolved from the same common base. They embodied the same idea and approach to operating systems: that an operating system could be generic to the hardware, with only a small fraction of the implementation being platform-specific, and that an operating system could be written in a portable high-level programming language (C). This, incidentally, explains C's near-mythical popularity.

There's a lot of history written on UNIX. One of the best and most insightful I've read is Eric Raymond's The Rise of Unix section in his A Brief History of Hackerdom. The entire article's worth a read, but that part I linked to should answer a lot of your contextual questions.