fprince Posted January 20, 2007 Share Posted January 20, 2007 Greetings y'all! This is my first post, so... Let me say hi :-) and thanks for creating and developing a solid knowledge base. Now to the point. This may be obvious but again I haven't seen that being clearly stated. A partition MUST start before the 1024 cylinder in order to be bootable. This information is probably especialy useful for those who are making a dual (multiple) boot system. So, no matter how many and which operating systems you are going to install and whatever boot loader you plan to use, make sure the partition for the boot loader starts below the 1024 cyl boundary. Please note that when you chose to use OS X' native boot loader and you did not abide to the 1024 cyl rule, your system ill boot only from the installation DVD but not the hard drive. Link to comment Share on other sites More sharing options...
Vapor1 Posted January 21, 2007 Share Posted January 21, 2007 so how can i make sure i started before the 1024 cylinder? Link to comment Share on other sites More sharing options...
donh Posted January 21, 2007 Share Posted January 21, 2007 Greetings y'all! This is my first post, so... Let me say hi :-) and thanks for creating and developing a solid knowledge base. Now to the point. This may be obvious but again I haven't seen that being clearly stated. A partition MUST start before the 1024 cylinder in order to be bootable. This information is probably especialy useful for those who are making a dual (multiple) boot system. So, no matter how many and which operating systems you are going to install and whatever boot loader you plan to use, make sure the partition for the boot loader starts below the 1024 cyl boundary. Please note that when you chose to use OS X' native boot loader and you did not abide to the 1024 cyl rule, your system will boot only from the installation DVD but not the hard drive. You can use grub to boot past 1024. Other boot loaders may work also. Don Link to comment Share on other sites More sharing options...
goodoporn Posted January 21, 2007 Share Posted January 21, 2007 Acronis OS Selector boots from anywhere. Link to comment Share on other sites More sharing options...
fprince Posted January 21, 2007 Author Share Posted January 21, 2007 (edited) @donh and goodoporn: Please note that I wrote about the partition for the boot loader/selector, not the OS. Sure, grub, Acronis, BootMagic and I'm sure many more boot selectors can boot from partitions starting beyond 1024 cyl but in order for them to work youm must place the boot selector itself before the 1024 cyl. In case you are using Mac OS' native boot loader, the boot loader and the OS are on the same partition which should start before that boundary. @Vapor1: The 1024 boundary is usualy around 8.4 GB from the begining of the disk. Edited January 21, 2007 by fprince Link to comment Share on other sites More sharing options...
cbmkgd Posted January 22, 2007 Share Posted January 22, 2007 Presently, my first OSX partition (in physical order) is situated at around 26GB. And I boot with darwin fine. Link to comment Share on other sites More sharing options...
donh Posted January 22, 2007 Share Posted January 22, 2007 @donh and goodoporn: Please note that I wrote about the partition for the boot loader/selector, not the OS. Sure, grub, Acronis, BootMagic and I'm sure many more boot selectors can boot from partitions starting beyond 1024 cyl but in order for them to work youm must place the boot selector itself before the 1024 cyl. In case you are using Mac OS' native boot loader, the boot loader and the OS are on the same partition which should start before that boundary. @Vapor1: The 1024 boundary is usualy around 8.4 GB from the begining of the disk. I think this is confusing the issue. The bootloader is usually in the MBR. The bootloader then passes control to the partition you choose. Don Link to comment Share on other sites More sharing options...
Vertigo50 Posted January 22, 2007 Share Posted January 22, 2007 It's a non-issue if you're using any bootloader besides Windows, because any good bootloader program will install itself on a partition that is bootable. It knows where to place the startup file so that it will boot. Link to comment Share on other sites More sharing options...
fprince Posted January 22, 2007 Author Share Posted January 22, 2007 Without using any external boot loaders, I had my OS X installed on the last partition, far beyond the boundary and it would boot only from the installation DVD. @cbmkgd: the boundary is expressed in cylinders, conversion to GB depends on the geometry of the drive @Vertigo50: BootMagic that comes with Partition Magic is considered to be a good boot-loader, it's even described in the installation guides, yet you can install it on any FAT partition including those non-bootable. @donh: Not all boot managers work the same way, MBR is only 512 bytes! Please refer to this article for explanation: http://en.wikipedia.org/wiki/Master_boot_r...m_bootstrapping Link to comment Share on other sites More sharing options...
cyclonefr Posted January 22, 2007 Share Posted January 22, 2007 This is weird, I can boot on both my XP partition and OSX partition (ie, Darwin bootloader or XP bootloader) and one of them is beyond the 1024 limit. Link to comment Share on other sites More sharing options...
donh Posted January 22, 2007 Share Posted January 22, 2007 (edited) Without using any external boot loaders, I had my OS X installed on the last partition, far beyond the boundary and it would boot only from the installation DVD.@donh: Not all boot managers work the same way, MBR is only 512 bytes! Please refer to this article for explanation: http://en.wikipedia.org/wiki/Master_boot_r...m_bootstrapping The reason it would not boot is probably covered here. http://forum.insanelymac.com/index.php?sho...c=30322&hl= The PC always reads the MBR (first 512) then passes control to what ever is discribed there. I wouldnt bet my pay check but I am prety sure the darwin boot loader will work past 1024. It does need to be a primary partition and active. Don PS Hey Ramjet, why not do one of your famous copilations on boot problems so people can find them. Edited January 22, 2007 by donh Link to comment Share on other sites More sharing options...
cbmkgd Posted January 22, 2007 Share Posted January 22, 2007 (edited) Without using any external boot loaders, I had my OS X installed on the last partition, far beyond the boundary and it would boot only from the installation DVD. @cbmkgd: the boundary is expressed in cylinders, conversion to GB depends on the geometry of the drive My first OSX partition, beyond 26GB, is at cylinder 3423. Edited January 22, 2007 by cbmkgd Link to comment Share on other sites More sharing options...
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