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"free" miboot on OldWorld Mac

On Aug 11, 2004, at 3:44 PM, Sven Luther wrote:
On Wed, Aug 11, 2004 at 03:12:49PM -0400, Rick_Thomas wrote:
Here are a few practical suggestions:

Has anyone looked at "inside Macintosh" or some of the other early Mac
technical docs?  I wonder if this code is, maybe, described there?

The real problem is that i am not a mac user, since i came from the amiga
world, and am currently working for genesi, who produce the pegasos and
MorphOS, which is an amiga OS reimplementation. We have information about the
boot block, but not the code in question. I know that it is mostly trap
instructions, and do some basic mac rom calls. If we were able to know which rom calls those are, and what they do, this would be enough for a clean room

I've been doing some research into this. In particular, I've been looking at the "Monster drivers tech note" available on Apple's Tech Support web site.

As I mentioned in another thread, calls to the OldWorld Mac ROM, for anything other than a floppy, are actually calls to a patched/extended image of the ROM -- patched and extended with whatever driver information is needed to help the ROM code read from the device in question on that particular type of Mac. Those patches/drivers are licensed IP of Apple (or a third-party vendor if Apple doesn't directly support booting from the device in question.)

The patches/drivers get installed on your hard disk by the Apple disk partitioning utility (or a similar third-party utility) which is only available as part of MacOS (or from the third party vendor).

It appears that re-writing the boot code part of miboot is really just the tip of a very large iceberg. To be truly "free", you have to provide a substitute for the patches and drivers.

It also appears that -- short of putting up with all the model specific quirks of quik -- there's no way to avoid using the MacOS disk partitioning utility at least once to install the driver/patch partitions on a disk if you intend to boot Linux from that disk.



PS -- I'll leave the question of what all this means for support of Debian Sarge on OldWorld Macs to wiser heads than mine.

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