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C H A P T E R 5
Software
in RAM appears to be a ROM, the
The Mac OS ToolBox image is kept in a file in the System Folder on the specified boot device. In order to avoid problems with internationalizing the name, the file is located by file type instead of by name.
In order for Open Firmware to retrieve the ToolBox image file, it must be able to read the selected boot device. If the ToolBox image file is on a partition that is on a RAID, encrypted, striped, or otherwise
The main incompatibility that
Boot ROM Contents
The Boot ROM contains the code needed to start up the computer, initialize and examine the hardware, provide a device tree to describe the hardware, provide hardware access services (RTAS), and control to the OS. The Boot ROM can be grouped into the following major pieces.
POST Code
This is the code executed when the computer first boots. This encompasses many of the traditional Mac ROM operations and is based on the hardware initialization code used in the past: setup and initialization of the processor and ASICs, a boot beep, an error beep, diagnostics, and transfer to Open Firmware.
A small debugging
60Boot ROM Contents