mystlynx Posted August 24, 2009 Share Posted August 24, 2009 I mean "pure GPT disk" not "hybrid GPT/MBR disk". Is that possible??? and also, how to revert a "hybrid GPT/MBR disk" to a "pure GPT disk" without data loss? Link to comment https://www.insanelymac.com/forum/topic/181331-install-windows-7-in-a-pure-gpt-disk-on-macbook/ Share on other sites More sharing options...
chokia Posted August 24, 2009 Share Posted August 24, 2009 Seems to me whenever you have windows on Guid, the disk become hybrid due to the fact that windows need NTFS, sound stupid as if GPT only made for mac. I wonder if "pure GPT" means windows is installed inside HFS+ partition on GUID, which is impossible. Link to comment https://www.insanelymac.com/forum/topic/181331-install-windows-7-in-a-pure-gpt-disk-on-macbook/#findComment-1233724 Share on other sites More sharing options...
srs5694 Posted August 24, 2009 Share Posted August 24, 2009 I mean "pure GPT disk" not "hybrid GPT/MBR disk". Is that possible??? AFAIK, it's possible only if the computer uses EFI rather than a legacy BIOS. Windows (even Windows 7 RC) refuses to install on a GPT disk on BIOS-based systems, and if you install on MBR and convert to GPT, Windows stops booting. A true Intel-based Mac, such as a MacBook, uses EFI, so in theory, you should be able to do it on your system, as specified in this post's subject line. (A tip: Don't place critical information only in a post's subject. Strangely, people often forget what's in the subject when replying to a post!) If you want to experiment, I suggest you try resizing your existing Mac partition(s) to leave some empty space and boot the Windows install disc. With luck, it'll install cleanly in a new GPT partition or two. Note that I've not done this, though. I don't know if it'll actually work, or how easy it'll be to select your OS even if it does work. It's conceivable that Windows will wipe out your Mac configuration. Proceed at your own risk. Note that the ability to boot from GPT on EFI-based systems is limited to certain versions of Windows. This won't work with most versions of Windows XP, for instance. I believe that's why Apple used hybrid MBRs in Boot Camp. See Microsoft's Windows and GPT FAQ for more information. and also, how to revert a "hybrid GPT/MBR disk" to a "pure GPT disk" without data loss? That one's easier. Do anything to the disk using GNU Parted or its GUI variants and it'll write a fresh protective MBR. Unfortunately, this will also destroy your boot loader (although a MacBook uses EFI, so this should not be an issue for you). My own GPT fdisk program has an option on the experts' menu to write a new protective MBR, and that option does not destroy the boot loader code. Seems to me whenever you have windows on Guid, the disk become hybrid due to the fact that windows need NTFS, sound stupid as if GPT only made for mac. No, NTFS is a filesystem; MBR and GPT are both partitioning systems, which exist at a lower level than filesystems. NTFS, like any filesystem, can exist on MBR disks, pure GPT disks, hybrid MBR/GPT disks, or disks with other partition maps entirely. The need for a hybrid configuration has to do with Windows' inability to boot from GPT disks on BIOS-based computers. This is a limitation of the Windows boot loader subsystem, not NTFS. Link to comment https://www.insanelymac.com/forum/topic/181331-install-windows-7-in-a-pure-gpt-disk-on-macbook/#findComment-1234008 Share on other sites More sharing options...
chokia Posted August 24, 2009 Share Posted August 24, 2009 Ok so on the same hardisk which of the following you called Hybrid GPT/MBR? EFI|Leopard EFI|W7|Leopard EFI|W7|Vista|leopard EFI|W7|Vista|XP|Leopard EFI|W7|Vista|XP|Tiger|Leopard EFI|W7|Vista|XP|Ubuntu|Tiger|Leopard Link to comment https://www.insanelymac.com/forum/topic/181331-install-windows-7-in-a-pure-gpt-disk-on-macbook/#findComment-1234047 Share on other sites More sharing options...
srs5694 Posted August 24, 2009 Share Posted August 24, 2009 Ok so on the same hardisk which of the following you called Hybrid GPT/MBR? It's impossible to say. Some background: GPT partitioning is a way to partition a disk using new data structures (relative to the 1980s MBR partition table). GPT incorporates a "protective MBR," which is a valid MBR partition table with a single partition of type 0xEE defined. This protective MBR is intended to keep MBR-aware but GPT-unaware tools from damaging the disk; such tools will see the disk as 100% occupied by a partition of an unknown type. A hybrid MBR is a variant on the standard GPT configuration in which the 0xEE partition is shrunk in size and up to three additional partitions are defined. These partitions point to existing GPT partitions (or at least they should; one of the problems with hybrid MBRs is that the MBR and GPT data structures can get out of sync with each other). The idea is to enable GPT-unaware OSes to access at least part of a GPT disk. A list of the partitions on a disk is not sufficient to determine whether it's an MBR disk, a standard GPT disk, or a hybrid MBR/GPT disk. The simplest way to spot such disks is to examine them with MBR disk utilities. If such a tool reports the presence of one 0xEE partition and one or more other partitions, then it's probably a hybrid disk. Technically, though, this test is inconclusive; it's possible to create a disk that meets these criteria but that has no valid GPT data structures. Link to comment https://www.insanelymac.com/forum/topic/181331-install-windows-7-in-a-pure-gpt-disk-on-macbook/#findComment-1234350 Share on other sites More sharing options...
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