Open Firmware

Open Firmware allows a system to load platform-independent drivers directly from a PCI device, improving compatibility. Open Firmware may be accessed through its command line interface, which uses the Forth programming language. Open Firmware was described by IEEE standard as IEEE 1275-1994. This standard was not reaffirmed by the Open Firmware Working Group (OFWG) since 1998, and was therefore officially withdrawn by IEEE in May 2005. Open Firmware defines a standard way to describe the hardware configuration of a system, called the device tree. This helps the operating system to better understand the configuration of the host computer, relying less on user configuration and hardware polling. For example, Open Firmware is essential for reliably identifying slave IC devices like temperature sensors for hardware monitoring, whereas the alternative solution of performing a blind probe of the IC bus, as has to be done by software like lm_sensors on generic hardware, is known to result in serious hardware issues under certain circumstances. Open Firmware Forth Code may be compiled into FCode, a bytecode which is independent of instruction set architecture.