Tutorial - How to triple boot OSX, Linux and Windows 8.1 with a shared Data Partition without any third party Win / OSX softwares

This is not a question, but rather a personal guide that has proved to be running successfully.

I would like to thank numerous sources, including Christopher Murphy's suggestions at:

Re: Repairing Boot Camp after creating new partition

Before proceeding, there are certain concepts needs to know:

Why Boot Camp does NOT allow further partitioning of drives after Windows has installed?

Answer: Because the way Apple configures the Mac to be recognized as non UEFI capable system on Windows.

Quote from Christopher Murphy based on the above line:

However, Windows on Macs right now use CSM-BIOS mode in Mac firmware that presents BIOS to Windows rather than EFI. Windows thinks it's on a BIOS computer, and therefore mandates the use of MBR for boot disks, rather than GPT. So that's why we have this hybrid MBR+GPT approach on Mac with Windows on it. You inherit the limitations of MBR, which is four primary partitions.

So what does it means?

It means that OSX + EFI + Recovery HD + Boot Camp partition = 4 primary partitions and thus any attempt to modify the disk will render booting issues of either system.

For more info on GPT (GUID Partition Table disks VS Master Boot Record or MBR in short, you may visit: http://msdn.microsoft.com/en-us/library/windows/hardware/dn640535%28v=vs.85%29.a spx)

So, how to overcome it?

The general guideline is to install ALL GPT ready OS first then create a Data partition, before installing Windows (Which is again, NOT supported GPT due to EFI configuration by Apple where end-users are not able to modify it).

Interestingly, since Mac Pro 2013 Late supports only Windows 8 and above, thus it is not known if this CSM-BIOS applies to it or not.

Do take note that GPT disks in Windows can only be booted when the system meets the 2 requirements:

http://msdn.microsoft.com/en-us/library/windows/hardware/dn640535%28v=vs.85%29.a spx#gpt_faq_win7_boot

1) Windows x64 version (Which is a must for newer Macs. If you cannot go to Boot Camp 5, then you need Windows 7 x86 or 32bit version)

2) UEFI system. However, Windows sees all Macs (With the possibility of Mac Pro 2013 Late is an exception. To be determined) as BIOS, or rather NON-UEFI system.

In short, booting on GPT disks is not possible for Mac in Windows.

Summary,

It is tested that a combination of the following will not work:

- OSX + Windows + Linux

- Windows + OSX + Linux

- Windows + Linux + OSX

Usually it can create the system un-bootable or OSX refused to install due to the system does not recognize such partitions and / or Disk Utility refused to format a free space. An example screen-shot is provided below:

The error message is shown as

Title: "Failed to erase volume" Message: "Failed to wipe volume, as an error occurred: MediaKit has reported that the device does not have enough free space to execute the requested operations."

The second thing is about the preparations we need.

1) 1X Windows 7 or 8 DVD or USB thumbdrive

1A) If you uses a DVD to install, you will need another thumbdrive to load the BootCamp drivers for Windows as well as may requires an external DVD drive for newer Macs

2) 1X Linux DVD of your choice. Personally I choose Fedora 20.

So ready? Let's go.

1. Using Disk Utility, shrink the OSX's partition size to what is needed. For me, I give OSX 150GB. Do NOT create any new partition.

Disk Utility should see something like below whereby only OSX partition is left with desired disk space. The remaining space are to be unused disk space for the moment.

Note: Click on the top most item that should start with the size of your HDD / SSD. Then clicked on "Partition" and specify the desired OSX size. Hit "Apply" after that.

2: Download Boot Camp drivers only via Boot Camp Assistant. The USB thumbdrive shall be used later after Linux's installation.

Boot Camp Assistant should see this:

I have only selected "Download latest Windows Support Files from Apple"

3. Insert Linux DVD, reboot Mac into EFI mode (The left most first "EFI mode").

Note 1: Before rebooting, please plugged in an Ethernet adapter because Wi-Fi drivers is not installed.

Note 2: For Thunderbolt adapters, it must be plugged in before reboot as hot-swapping is not supported under Linux. More on the tips at the end of this article.

Note 3: Press and hold "Option" after the screen turns black. Release Option key after you see the image as below: