iMac rev.A(1998) and the 8GB limit problem for booting Operative Systems.

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Level 1

5 points

iMac rev.A(1998) and the 8GB limit problem for booting Operative Systems.

I am changing the original harddrive(4GB) of my iMac to a 80GB hardrive.My intention is to establish several partitions on the new harddisk to install
several Operative systems: MacOS X,FreeBSD PPC,OpenSuSE LinuxPPC,Fedora Linux PPC,etc.,but there is the old problem of the first 8GB to install (and be bootable and run without problems) "any" operative system.
With Mac OS X it seems a real problem,but I do not know if with systems like FreeBSD,Linux it is the same.It seems a limitation of the harddisk controller of these first iMac models.So,is this a problem with OSs like BSDs,Linux etc.
or is it a problem of only MacOS X?

Thanks.

iMac first model (1998) rev.A, Mac OS 9.2.x

Posted on Dec 8, 2008 9:31 AM

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Answer 1

Dec 8, 2008 12:20 PM in response to alain renaud

I've personally tested the 8GB limit with Mac OS X and Mac OS 9. It definitely applies.

From what I understand, the old IDE controller only makes the first 8GB of hard drive space accessible during the startup sequence (before the OS is loaded). Therefore, if anything needed during startup is beyond the 8GB limit, startup fails. Technically, you don't have to partition it as long as all OS components needed during startup stay in the first 8GBs of drive space. Once startup completes and the OS takes over control, the rest of the drive space (up to 128GB) is accessible.

I think the limit would apply to all OS's. But I don't have proof with anything other than Mac OS X and Mac OS 9. If you try it, please let us know.

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Answer 2

rccharles

Level 6

13,037 points

Dec 9, 2008 12:11 AM in response to alain renaud

Yaboot is an OpenFirmware bootloader for Open Firmware based machines.
http://penguinppc.org/bootloaders/yaboot/index.shtml

Perhaps yaboot would work to round the eight gig partition limit. I think yaboot is on a separate partition. Which means it would be doing the loading of another partition.

Robert

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Answer 3

Dec 11, 2008 2:09 PM in response to alain renaud

And, in addition to everything else already said here, don't forget the firmware update.
http://docs.info.apple.com/article.html?artnum=75130

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