Technical Q&A HW101

Was that a path I just saw?

Q: Sometimes when booting the machine a small Mac OS logo flashes on the screen with what looks like a path below it. What does this indicate?

A: When Open Firmware looks for a boot device, it first looks to see if any snag keys are held down. If there are none, it looks at the environment variable boot-device. If the device specified in boot-device cannot boot the machine, Open Firmware will begin a search for another boot device. If it finds one that can boot the machine, it will flash the path to the found device on the screen and proceed with booting from the found device.

If Open Firmware cannot find a device to boot from:

• On NewWorld machines, it will display a folder on the screen and will alternately flash the Mac OS logo and a question mark (?) on the folder.
• On older machines, it will display an icon of a floppy disk with a flashing question mark. (?)

The device that actually booted the machine will be reflected in Devices:device-tree:options:boot-path.