Difference between chainloader & boot directly from MBR?

[trip2me]

I'm Thinkpad X60 tablet & vista user.

I have installed Mac OS Tiger also.

 

Yesterday, I update IBM RnR(Rescue and Recovery) bootloader in MBR(master boot record).

 

So, my hard disk has 3 primary partitions; first = hidden RnR software, 2nd = Vista, 3rd = Mac.

I have used vista's boot manager for multi booting.

 

There is a boot sequence.

vista: MBR -> vista boot manager -> vista

mac : MBR -> vista boot manager -> GRUB4DOS in vista -> darwin-bootloader in mac -> Mac

 

In MBR, there is a IBM RnR bootloader which check if user press F11 function key while boot process.

If pressed, MBR bootloader unhide first partition and boot RNR software.

If not, pass the boot process to active partition's first boot sector.

 

I have a question about Mac(tiger)'s boot process.

 

In case of booting mac from Windows,

I understood that darwin bootloader can't boot without active flag assigned mac partition.

It is a problem related with boot2( bootloader kind of linux's stage2 ).

So we need to change active partition flag to mac partition.

 

 

The Mac can load well using Grub4DOS's CHAINLOADER METHOD on Vista.

 

Grub's menu.lst is

timeout 0

default 0

title Mac OS X 10.4.11

rootnoverify (hd0,2)

makeactive

chainloader +1

boot

 

 

But when I trying to BOOT MAC DIRECTLY FROM THE MBR with active partition flag, Mac bootloader(maybe boot1) of first sector of mac partition HANG OUT with "HFS+ partition error" message.

It's little bit tricky.

 

What is the difference of processing between boot directly from MBR and boot from grub's chainloader method?

I think both of way start from Mac's first boot sector( boot1 ), and then I tested it using boot1.s with debug flag on, it turns out true.

 

Why I failed to boot Mac directly from MBR?

Is there something secrets with chainloader?

I think Mac must be loaded whether or not using chainloader.

 

I don't want to see a 'HFS+ partition error' message when boot from directly from MBR.

GRUB in MBR is simple solution, but I must keep RnR bootloader in MBR.

 

Is there any answer?