Understanding MAC OSx86 for Dummies

I wrote an article, a while ago, on How to install OSx86 on PC. It had been a big success for the readers because of the ease of installation. Let’s take it a step further where I`ll introduce you to some basic terminologies and concepts for a MAC OSx86 system.

Most of the users today migrate from Windows and this is the reason they have no understanding of the Mac Platform. Let’s do a Quick FAQ for Osx86 and Mac OS Platform:

Q. Can I Insall MAC OS X Leopard Retail DVD on my PC?

A. NO. Infact, it had been that easy, OSx86 project would have never come into existence. In actual, OSx86 has a MODIFIED kernel that let’s you support all your x86 systems with Mac OS. During Installation, it installs certain drivers (.Kexts) which are required to support your chipset, graphics and processor. This is so because the hardware used on macbook pro is pretty different, The chipset, graphics, audio it uses are all very different and Retail DVD will not support them.

Though it’s possible to install from Retail DVD but the procedure is very tough for most of the users since it involves compiling custom kernels(different for each Intel, AMD) and finding and compiling drivers. OSx86 is a much better and easier way of doing it.

Q. What are the limitations of OSx86?

A. Mostly OSx86 is able to do 95% of the stuff that a real MAc can do. Bad side is certain drivers are unstable or doesn’t exist for osx86. Best example is for the Intel 3945ABG wireless, it’s not supported by OSx86 though there is a open source project called iwidarwin which makes drivers for this card, but It’s not stable.

Q. Why there are so many Flavors of osx86 and which one is for me?

A. None of them is perfect, but as time passes, they approach perfection. iPC is the most advanced you can get, keeping into consideration that it supports largest database of hardware, followed by Kalyway, iDeneb and others. To answer “Which one is for me?”, You should check for is your Hardware compatibility List (HCL) i.e. which Flavor supports your hardware on OSX86 wiki.

Q. What is a kernel ? You referred to something called “Kernel”. what is that anyway?

A. A kernel is in short terms the “core” of the OS. It controls all low level operating functions. Kernels exist in all Linux and UNIX based systems, including Mac OS X. Infact, it exists in windows too, but Microsoft never exposed it to the user. In Mac OS X the kernel is located in the root of your hard drive (/) and is named “mach_kernel” by default. If you have a vanilla based system then replacing the kernel is most likely not necessary, however if you have an AMD or SSE3 incapable processor then a patched kernel will likely be required.

Q. What are kexts ? Some kind of Drivers?

A. Kexts, or kernel extensions are drivers to support various kind of hardware. Kexts are installed to /System/Library/Extensions/.Kext files often have the “.kext” extension and allow for extra hardware support and and in the case of OSx86, to replace Appleʼs original drivers with ones that are optimized for use on PCs.All the drivers which are not supported by Apple are custom developed and packaged in osx86.

Q. What is ACPI?

A. Advanced Configuration and Power Interface. ACPI specification is an open standard for unified operating system-centric device configuration and power management. ACPI defines platform-independent interfaces for hardware discovery, configuration, power management and monitoring. The specification removes device management responsibilities from legacy firmware interfaces. ACPI is an attempt to consolidate and improve upon existing power and configuration standards for hardware devices.

Q. What is a Vanilla ?
A. Vanilla is a kernel developed for Intel Core Duo platform. A vanilla compatible system is a computer capable of running OSx86 with minimal modifications (no patched kernel, compatible with Apple software updates).

Q. What is DSDT ?

Ans. DSDT is a part of ACPI. Actually DSDT tells OS how to interface with the hardware. OSX has an incomplete ACPI implementation which supports only a subset of DSDT. By replacing DSDT we can declare essentially the same interface but in the way that OSX understands. This potentially can solve nearly any ACPI-related problem (except if OSX bypasses ACPI). Other usage case is emulating by the means of DSDT features or hardware components not present on your system. But this is limited to devices that use ACPI. This can include resolving of issues like Failure to sleep, standby, recover from sleep, standby, monitor turn off, hibernate, etc.

Q. What is DSDT patching?

A. This is an area very rarely delved into, and is something that some of even the most experienced users dare not venture. In reality, its not dangerous, rather, it can be painfully hard at times.

DSDT is a table found in your computerʼs BIOS that controls ACPI (power, time, etc.) functions. Starting from OS X 10.5.6 Apple decided to start checking for faulty DSDTs when it boots. Obviously the PCs DSDT comes back as faulty so it will not boot. The only way to counteract this is to make a dump of the DSDT in the BIOS and patch it properly for Darwin. First of all, you need a modified bootloader that will support DSDT override. This installer includes just that, using the “Install PC_EFI v9 Chameleon Edition 1.0.x” checkbox. Now you need a patched DSDT file that will be copied to / dsdt.aml. To create DSDT dumps you can use the DSDT Patcher (also included in the Extras folder) but this is an advanced method, and often UOI plugins will include a DSDT file that you can install easily with this installer. However beware, even if you have the same motherboard DSDTʼs can vary by BIOS version so try to make sure that you have the same BIOS version as what is specified in the plugin.

Q. What is the difference between SMC & RTC ?

A. The SMC is basically System Management Controller. By resetting the SMC you can resolve some computer issues such as not starting up, not displaying video, sleep issues, fan noise issues, and blah-2. While The Real Time Clock (RTC) is a chip on the logic board that controls the date and time functions of the computer. If the computer is experiencing a booting issue, resetting the RTC may resolve it.

Q. What is EFI emulation ?
A. EFI is the Extensible Firmware interface found in Real Mac. EFI is basically the “BIOS” of a Mac. For a computer to be properly recognized as a mac and to have the most compatibility it must have EFI. The problem here is that PCs do not have EFI. Developers have counteracted this problem by using EFI emulation which enables basic EFI function calls through a specially modified boot-loader. EFI distributions for OSx86 include PC_EFI and Chameleon. Nearly all OSx86 installs have some form of EFI emulation installed, so this is not necessarily something to worry about. EFI emulation is required to use vanilla (unpatched) kernels and kexts, and to use GUID partition maps and EFI strings.

I hope I cleared most of your doubts encircling OSx86 world. In case you have more doubts, feel free to ask, I`ll be delighted to help you.

Tip: In case you need quick assistance, contact me on Twitter: @taranfx