[rescue] G3 Score

nate at portents.com nate at portents.com
Wed Mar 8 22:40:26 CST 2006

> How *peculiar*.  Do you happen to know where that limit comes from?  An
> 8G limit wouldn't surprise me (a 24-bit field for a sector number, with
> 512-byte sectors).  A limit close to that but nearly two hundred megs
> under it, though, does surprise me.

The limitation comes from the openfirmware driver for IDE.  When booting
OS 9, open firmware actually boots the OS 9 ROM, which then loads it's
drivers and boots a hard drive.  So, there's no issue booting a bigger
than 8GB partition in OS 9, because the classic IDE driver (in the classic
ROM) isn't limited to 8GB.

Also, you can boot OS X on a greater than 8GB partition on a SCSI drive or
any storage card that has it's own openfirwmare drivers (such as IDE and
SATA cards).  The 8GB limitation is solely with booting OS X exclusively
on the on-board IDE, and since the firmware is not flash upgradable, and
Apple never came out with a ROM SIMM upgrade that fixed the problem (they
could have), it's stuck around.

8000MB is safer to say than 8192 simply because with the partition map
taking up some space before the first partition, you have more like 8191
or 8190, but hey if you say 8000 no chance you'll go over 8192 with the
first partition.

- Nate

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