Tracking BootX

When the Open Firmware startup program in BootROM locates and selects the Mac OS X operating system, it transfers control to BootX (a process that Open Firmware starts from /System/Library/CoreServices on the startup disk). The primary task of BootX is to initialize the kernel environment and the drivers (such as the drivers for I/O buses) needed to boot the system. In addition, BootX starts up the kernel initialization process.

When Open Firmware attempts to find BootX, one of the following icons will appear, indicating these results:

• Metallic Apple logo Found BootX

  

• Circle with slash Could not find BootX on the startup volume

  

• Flashing square with globe Looking for BootX on a remote disk via the network

  

• Small metallic spinning globe Found BootX on the network

• Flashing question mark over a folder or floppy disk icon Open Firmware did not find a startup disk (locally or on the network)

  

If Mac OS X components have been renamed or moved from the root level of the startup disk, a broken folder icon will appear. A black belt may appear around a folder icon if a Mac OS 9 restore has been installed incorrectly using the Restore discs that came with the computer.

When loading the kernel environment, BootX first attempts to load a previously cached set of device drivers. If this cache is missing or corrupt, BootX searches /System/Library/Extensions for drivers and other kernel extensions whose OSBundleRequired property is set to the appropriate value for the type of boot. (This is either a local or network boot, depending upon the current selection in Startup Disk preferences.) You can recognize this stage by the metallic Apple logo and the spinning gear that appear on the screen.