Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Open Firmware, or OpenBoot in Sun Microsystems parlance, is a standard defining the interfaces of a computer firmware system, formerly endorsed by the IEEE. It originated at Sun, and has been used by Sun, Apple, IBM, and most other non-x86 PCI chipset vendors. Open Firmware allows the system to load platform-independent drivers directly from the PCI card, improving compatibility. Open Firmware may be accessed through its Forth language shell interface. It achieves essentially the same functionality as the later EFI standard initiated at Intel, with lower overhead.