The OpenBoot architecture provides a significant increase in functionality and portability when compared to proprietary systems of the past. Although this architecture was first implemented by Sun MicroSystems as OpenBoot on SPARC systems, its design is processor-independent. OpenBoot is based on the IEEE Std 1275-1994 Standard for Boot (the standard is available from IEEE, which might require membership or a fee for access).
For recent SPARC systems, OpenBoot firmware is executed after Virtual Machine (VM) is started.
The primary tasks of OpenBoot firmware are to:
Determine the hardware configuration and initialize I/O devices by running the FCode driver for each I/O device.
Boot the OS from either a storage device or from a network.
The primary tasks are described in Booting and Resetting a Virtual Machine.
The OpenBoot CLI is based on an interactive command interpreter that gives you access to an extensive set of functions for hardware and software development, fault isolation, and debugging. For details, see Accessing the OpenBoot CLI and Getting Help and Using the OpenBoot CLI.
A number of OpenBoot operating characteristics are controlled by configuration variables that are stored in nonvolatile memory. If needed, you can change the configuration variables default values to tailor operating characteristics to your environment. For details, see Setting Configuration Variables and Setting Security Variables.
OpenBoot provides commands that you can use to gather information about the system hardware. Some commands also perform a low level sanity tests of the hardware without a running OS. For details, see Interrogating the System With OpenBoot Commands.
You can use the OpenBoot nvramrc configuration variable to store user-defined FORTH commands that are executed during start-up. For details, see NVRAMRC Overview.