A way to enable OpenBIOS on PearPC?

[ARCHIVED] About PearPC, a mostly obsolete PPC Mac emulator for Windows and Linux to run MacOS X 10.1 up to 10.4. Using QEMU is now recommended.

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wizoomer95
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A way to enable OpenBIOS on PearPC?

Post by wizoomer95 »

I did post this on pearpc.net, and someone suggested to cross-post it here on E-maculation forums. So, here it goes:
Many people consider this project deserted as it only allows booting of old versions of OS X, and OSx86 has come a long way since the Apple Intel Transition. Yet, one of their technologies, Boot-DFE (a hacked version of Boot-132) might have a similar principle on how we could enable OpenBIOS on PearPC.
When Leopard was released, PearPC users were dissappointed as it couldn't boot in PearPC. Yet, on the other side of the net, OSx86 was reaching other problems. Intel Macs running Leopard didn't use a TPM, which is what they bypassed to run the Intel version of Tiger on an x86 PC. Instead, its OS DRM relied more heavily on EFI, the replacement for BIOS in PCs. Since most Windows PCs still ran BIOS, it was harder to run Leopard on an x86 PC unless you were a developer. The first way they did this was creating patched kernels that circumvented the EFI requirements. Finally, Boot-DFE (aka David Elliot's Boot-132) came onto the scene. It worked in a different manner than patched kernels. It was a bootloader that emulated EFI.
Here's how it works: Another Linux Bootloader, ISOLINUX for CDs, loaded Boot-DFE into a RAM Disk. All it was is a Darwin Bootloader for x86 PCs with a few kernel extensions, or drivers, from Apple's Boot-132 (Developers' way of running the XNU kernel on generic x86 PCs) and an EFI emulator. From there, you could swap the CD for the Retail Leopard (or recently Snow Leopard) Install DVD, and select it as a boot device. This emulator made OS X think the PC was a real Mac because of the emulated EFI. You would proceed to Install OS X to the hard drive; at reboot, you would swap the Install DVD with the bootloader CD, and this time select the Hard Drive as your boot device. After finishing the Installation, you would copy the code to the hard disk, enabling you to boot OS X without the bootloader CD anymore.
You may ask, "What in the world does this have to do with PearPC?" A lot. What we do have is some Linux support for PearPC as well as Darwin, an open source OS similar to OS X's Terminal, or command-line interface. They can load from PROM, or PearPC's Open Firmware implementation. We might not be able to do the CD swapping part as it was kind of buggy from the beginning with the old "Change CD" Button, but we could do something similar to Boot-DFE, except this time emulating OpenBIOS on PearPC. We would either write or better yet find a bootloader compatable with PROM that would load a RAM Disk into the emulated Mac. The RAM Disk would contain a bootloader with a OpenBIOS Emulator. Using maybe Redscorp's Quad IDE Build, we could then select a second CD/DVD with the desired OS Installation as the boot device. It would use the emulator as the firmware, and make the OS think that PearPC is running OpenBIOS. At the reboot, restart PearPC, boot from the OpenBIOS Emulator again, and select the hard drive as the boot device. Finish the installation, and copy the code to the Hard Drive.
What do you guys think? Would this work? I am an amateur developer so I wouldn't understand PearPC's source code, but I think it might work; we would see PearPC running OpenBIOS really soon.
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Cat_7
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Post by Cat_7 »

Hi,

I saw you post on pearpc.net, but didn't react as the development situation around pearpc is more then quiet. Combine that with the fact that e.g. boot132 is Intel centered and not PowerPC, the processor/architecture PearPC emulates. Have you considered that? I guess the idea might have some merit, but I don't see anyone taking it up soon.
The emulators we are concerned with also get limited attention from developers since the main developer stopped. We are more or less in maintenance mode. So I don't have high hopes for your project. :x

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Cat_7
wizoomer95
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Post by wizoomer95 »

Cat_7 wrote:Hi,

I saw you post on pearpc.net, but didn't react as the development situation around pearpc is more then quiet. Combine that with the fact that e.g. boot132 is Intel centered and not PowerPC, the processor/architecture PearPC emulates. Have you considered that? I guess the idea might have some merit, but I don't see anyone taking it up soon.
The emulators we are concerned with also get limited attention from developers since the main developer stopped. We are more or less in maintenance mode. So I don't have high hopes for your project. :x

Best,
Cat_7
I was trying to say that we would need to develop a bootloader similar to boot-132, not use it in PearPC. I know that boot-132 is only for x86 processors (Boot-DFE can boot off of any PC, yet compatible hardware is required for OS X installation. In fact, there is a thread on InsanelyMac that shows how you can patch boot-132 for AMD processors.) You're right in saying that we would have to rewrite the code for the PowerPC arcitecture to use it in PearPC. I'm just trying to use it as an analogy.
And PearPC is not completely deserted as many open source projects are centered around PearPC. In fact, I still see that PearPC could rise again with the addition to new OSes that could be installed with OpenBIOS but not with PROM. So, don't give up on it quite yet!!
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ClockWise
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Post by ClockWise »

What open source projects are centered around PearPC?
wizoomer95
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Post by wizoomer95 »

ClockWise wrote:What open source projects are centered around PearPC?
A lot are on SourceForge. It is mostly centered around one of 2 things:
1. It could be a GUI for Windows for launching PearPC and managing configuration files. One, for example, has a VirtualBox-like style for a GUI.
2. It could either be BartPE or basic Linux (like maybe DSL) requirements for configuring PearPC into a standalone OS, enabling x86 computers to run Mac OS X (PPC versions) as a primary OS. A new one is being planned, called PearOS, which uses GNU/GPL Linux.
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Cat_7
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Post by Cat_7 »

If I remember correctly, the ideo basing PearPC on openbios was abandoned due to insufficient progress over at that project.
The other projects mentioned haven't delivered anything usefull, and are in a sleeping state from at least 2006.

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Cat_7
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