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srs5694

srs5694

Member Since 15 May 2008
Offline Last Active May 08 2012 01:18 AM
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Posts I've Made

In Topic: logic partition problem?

27 February 2012 - 08:54 PM

Actually, it is possible to boot OSes from logical partitions -- Linux can be installed in this way, among others. The trouble is that you need a boot loader that supports that type of installation, and the Microsoft-style boot loaders can't handle it. My knowledge of Hackintosh boot loaders is limited, so I don't know what their precise capabilities are, but the last I checked, installing to a logical partition was discouraged.

You might be able to get it to work by using GRUB 2, which includes support for booting OS X kernels; however, this support is primitive and flaky compared to typical Hackintosh boot loaders such as Chameleon.

Another option might be to convert the partition from logical form to primary form. Not many partitioning tools can do this, but one that can is FixParts. There are probably other tools that can do this, but I'm not sure what they are.

In Topic: refit does not boot windows anymore

27 September 2011 - 11:55 PM

On a macbook pro beginning 2011, I installed windows 7 (sp1 64 bit) using bootcamp, then refit.
I later used windows to add an extra partition for data (an extended one with a logical one inside in fact), to get the following disk scheme:
efi, osx, win os, 128mb free, win data (ntfs, logical partition in an extended one)


I realize you posted later that you've worked around the problem, but the fact is that your hard disk is in an extremely dangerous state. Your MBR and GPT data no longer match each other. Depending on the details of how this is laid out, you could end up having one OS overwrite another OS's data. OTOH, it could be that there's no risk of this happening, but future partitioning operations could cause you to lose access to your Windows data partition.

As a general rule of thumb, you should never attempt to modify a disk with a hybrid MBR (which is what you've got) using Windows' disk partitioning tools. You should also never use extended or logical partitions on a disk with a hybrid MBR. Both practices are recipes for disaster.

It's probably possible to repair this damage, but I can't be certain without seeing details of both the GPT and the MBR partition tables. You can provide that information by running the following commands in OS X:

sudo gpt -r show disk0 
sudo fdisk /dev/disk0

Please post the results here, between [ code ] and [ /code ] tags for legibility.

In the meantime, you might want to read up on hybrid MBRs at my Web page on the topic.

Note that I read this forum rather sporadically. I'll make it a point to check back regularly for a couple of days, but if you post after that, please send me a PM or an e-mail (you can use the link on my hybrid MBR Web page) to alert me to the new information.

In Topic: Use Chamelon to boot Windows 7 EFI ?

27 September 2011 - 11:20 PM

AFAIK, it's not possible with Chameleon, but it is possible with UEFI DUET:

http://www.rodsbooks...uefi/index.html
https://gitorious.or...64_BIOS_to_UEFI
http://www.insanelym...howtopic=186440

In Topic: Question about Intel-UEFI-Bios!

27 September 2011 - 11:18 PM

Linux supports EFI since 2000, Windows Vista requires SP1 for EFI boot, but not Win7. And Chameleon works just fine with it


I believe you're confusing the Extensible Firmware Interface (EFI) and the GUID Partition Table (GPT).

EFI (or its newer variant, UEFI) is software that's stored in a chip on the motherboard -- that is, firmware. Intel-based Macs use EFI, and many recent PCs use UEFI. Older (and some current) PCs use the older Basic Input/Output System (BIOS) firmware. Most PC OSes boot in BIOS mode, although support for (U)EFI booting has been slowly appearing. In Linux, aside from some exotic non-x86 implementations, (U)EFI booting has only been practical for a couple of years, and even now most distributions provide weak support. AFAIK, all Hackintosh boot loaders are BIOS-based, but they typically set up a partial or even a complete EFI environment atop the BIOS to make OS X happy.

GPT is a partitioning system used on hard disks. It's defined as part of the EFI specification, but you can use GPT on a BIOS-based computer. GPT is likely to eventually replace the Master Boot Record (MBR) partitioning system that most PCs have used for 30 years, since MBR has a disk size limit of 2 TiB (assuming a 512-byte sector size) and GPT's limit is much higher. Intel-based Macs ship with GPT hard disks, and Apple's OS X installer wants to see a GPT disk (but there are ways around this limit). The support figures you mention (Linux since 2000, Vista since SP1, Chameleon works with it) all apply to GPT, but they don't all apply to EFI.

As to the original question, I don't know how practical it is to install OS X on a UEFI-based PC, at least in UEFI mode. AFAIK, all the common Hackintosh boot loaders are built for BIOS, which means that if you boot the PC in UEFI mode, those BIOS-based boot loaders won't work. That said, most UEFI implementations let you switch between UEFI mode and a BIOS compatibility mode, so it is possible to install OS X as you would on an older BIOS-based computer -- ironically, you use an EFI emulation atop a UEFI firmware's BIOS compatibility mode to do the job. If other OS(es) on the computer boot in UEFI mode, though, you may need to manually switch modes when booting between OSes, which may be awkward. Also, there may be a UEFI-mode Hackintosh boot loader available or under development, or a way to get a Hackintosh to boot more directly using the built-in UEFI implementation. If so, I don't know where the instructions are to do such a thing. (I'd be interested in this myself, since I'm planning to build a new computer before too long, and it will be UEFI-based.)

In Topic: Installing 10.6.7 on a 3 TB Drive

07 July 2011 - 11:29 PM

I don't know about Chameleon specifically, but a lot of boot loaders include 32-bit disk sector number limits, and that limits their ability to boot anything from above the 2 TiB mark. If some critical file happens to fall above that point, the boot will fail. I can't say with certainty that you're running into this specific problem, but you might be. Certainly it's worth repartitioning your disk and trying again. IMHO, this is advisable anyhow -- for flexibility when re-installing, it's best to separate your OS system files from your personal data files so that you can wipe the OS clean without affecting your personal data. With a 3 TB disk, this is even more important, since it's hard to back up and restore so much data, should you need to completely wipe the installation partition.
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