OSx86

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OSx86 10.4.8 (semthex's kernel) on a Pentium M

OSx86 is a collaborative hacking project to run Apple's Mac OS X operating system on non-Apple personal computers with x86 architecture processors. A portmanteau of OS X and x86, the effort started soon after the June 2005 Worldwide Developers Conference announcement that Apple would be transitioning their personal computers from PowerPC to Intel microprocessors.

Initial efforts revolved around leaked copies of the Development DVD that was released by Apple as part of the Developer Transition Kit that Apple made available to developers for $999. The first patches centered around circumventing the Trusted platform module (TPM) that was included on the motherboard of the Developer Transition Kits. The TPM was required by the Rosetta technology that allowed software compiled for the PowerPC architecture to run on Intel-based architecture. Removing this requirement allowed Mac OS X to be installed on non-Apple computers. Rosetta also required microprocessors that included SSE3 instructions. Patches were released to the community that emulated these instructions with SSE2 equivalents and allowed the installation on machines without SSE3 support (with a performance penalty).

In October 2005 Apple released a 10.4.3 update to developers that required NX bit microprocessor support.^[1] Patches were released to circumvent this. ^[2]

On January 10, 2006, Apple released Mac OS X 10.4.4 with the first Intel-based Macintoshes. These machines used an Extensible Firmware Interface (EFI) chip instead of the traditional BIOS chip found in most current x86 platforms. On February 14, 2006 an initial "crack" of OS X 10.4.4 was released on the Internet by someone using the name Maxxuss. ^[3] Within hours, however, Apple released the 10.4.5 update^[4], which was patched again by Maxxuss in less than two weeks. ^[5] On April 3, 2006 Apple released their 10.4.6 update^[6] and again patches were released within two weeks that allowed users to install most of this update on non-Apple computers, although not the updated kernel included with 10.4.6. These patches were released by a person using the name SemjaZa and compiled by a person using the name JaS. In June, once again JaS released the 10.4.7 Mac OS X update for non-Apple computers, although it still uses the 10.4.4 kernel.

Up to the release of 10.4.8 update, kernel from 10.4.4 was still being used with all updates that have been released. However as more updates were released more and more frameworks are relying on updated kernels which has lead to 10.4.8 having the most problems encountered by users so far due to the huge gap between 10.4.8 frameworks and 10.4.4 kernel. Apple has also started making more use of SSE3 instructions on their hardware making it even more difficult for users on SSE2 platforms to get a full system running.

Two programmers, calling themselves Mifki/Vitaliy and Semthex, released new kernels by taking with opensource XNU tree and applying necessary patches to run the kernel on non-apple hardware. Mifki's goal was to release the kernel with as few patches as possible, that will be able to run on close-to-Apple hardware. Semthex's goal was making his kernel more compatible with legacy hardware, missing some of the crucial features.

Both kernels allowed most of the updated kexts/frameworks to work, making properly configured white-box PCs operate more like genuine Apple computers. While Mifki has only updated his kernel once, Semthex updates it regularly and has added AMD, VMWare and SSE2-support in his newest version. Semthex released his hacked kernel sourcecode on his webpage. On December 24 he also released the latest patches for the SSE3 kernel as a diff file for his original source tree as a Christmas present to the community. Special attention should be given to the SSE2 emulation which Semthex developed together with Rufus. This emulation is the first really complete emulation of all SSE3 instructions in the OSx86 history. The old SSE2 emulation were incomplete and only emulated 3 of the available SSE3 instruction and slow compared to the new emulator. This effort enabled even SSE2 OSx86 users to run e.g. iTunes 7 or high end 3d applications on their computers.

In the early days of 10.4.8, an Intel-SSE3 only install DVD was released by JaS, which includes Vitaliy's and Semthex's kernel. A few weeks later, "tubgirl" released an AMD-SSE3 install DVD. With Semthex's successful completion of the SSE2 Kernel, JaS released a SSE2-SSE3 universal DVD and announced his retirement from the scene after seven successful DVD releases.

In March 2007 the OSX86 community made some significant progress with the development of a Live DVD. The Live DVD allows booting to a working system with MacOSX 10.4.8. Several movies appeared on the web demonstrating this.^[7]

On March 24, 2007, Jason Swadley announced in an email and forum post that he would be selling the OSx86, InsanelyMac and OnMac.net site. The sale is to allow him time to earn a masters degree.