The History of OSx86 is a long and storied one, starting from its early roots as a BSD kernel. This page attempts to create a definitive history for OSx86.
OSx86 started its days as the BSD mach kernel, and retains this name today. This also explains the use of many Unix and BSD terms in the operating system, including daemons, the BSD subsystem, and the entire Terminal infrastructure. This key fact also makes OS X quite portable.
However, the history of OSx86 rapidly digresses from here. The mach kernel from BSD was incorporated into the NeXTSTEP operating system, a venture by Steve Jobs, which, interestingly enough, was availible for 68k, x86, SPARC, and RISC platforms, continuing BSDs tradition of portability.
It is here when OSx86 as we know it came into existance, at least, in a primitive form. After falling through with both IBM's Pink and Be's BeOS, Apple settled on a new player to code it's massive OS update for the 21st, Steve Jobs. Bringing the NeXTSTEP code base with them, they quickly began work on a new version of MacOS, with the code name "Rhapsody". This contained a few interesting features: yellow box, a universal toolkit for OS coding, based on Java technology, blue box, a MacOS Classic emulation environment, and the rumored red box. Although yellow box fell through, it's influence is still felt today.
However, the most important element of Rhapsody was once again it's portability. Released publicly to developers in the form of DR1 and DR2 (DR standing for Developer Release), it was distributed in two forms -- PowerPC and x86.
This is where the classical history of Rhapsody ends, with codename "Marklar". Although it has never been publicly confirmed that this codename existed, it is rumored to have been the project to keep OS X for PowerPC in sync with Intel builds. Although it's obvious that these ports would not have been production quality, it's quite likely that these rough ports were maintained to reduce workload if, or, as we now know, when, Apple decided to move to Intel.
Finally, we reach modern day. OSx86 has been distributed through rented Developer Kits, which Apple has offered to paying ADC members. There have been 3 released builds, each of which begin to perfect the software and bring it up to speed with it's sibling, OS X for PowerPC.
1977 - BSD offers it's first release for PDP-11 1989 - NeXTSTEP 1.0 released, based on BSD mach kernel 1992 - NeXTSTEP 486 (3.0) released, adds support for x86 1995 - Final verison of NeXTSTEP, 3.3, is released, supports 68k, x86, SPARC, and RISC platforms 1997 - Apple acquires NeXT Inc. and begins work on Rhapsody, releasing DP1 in September 1998 - Apple updates Rhapsody with DP2 1999 - Mac OS X Server is released, x86 support has strangely disappeared from Rhapsody, however is retained in the first version of the open source Darwin, released by Apple 2000 - Mac OS X Public Beta 1 is released, once again, with no x86 support, this trend continues in OS X releases 2000-2005 - Apple Developers maintain an Intel port of OS X, supposedly codenamed "Marklar" 2005 - Apple announces the return of OS X on x86, with new Mac Intel boxes on the way. Apple releases multiple builds of OS X for Intel to developers owning Developer Transition Kits