Loading the System Image

The last action of the power-up initialization code is to hand control to the initial loader which loads the system image into physical memory and jumps to the image entry point.

If the system image is already stored in non-volatile memory on the board, the initial loader is not required, and the initialization code terminates by jumping to the entry point of the system image.

The initial loader may either be the firmware provided by the board, or the ChorusOS Boot Monitor (see bootMonitor(1M)).

Most development boards are provided with a standard firmware power-up initialization code and loader in PROM. This firmware is able to download a system image from a local device or from the network (for example, PPC-Bug firmware on platforms in the PowerPC target family). Sun Embedded Workshop provides tools that build the ChorusOS system image in the format required by the firmware loaders supported.

For some target families it is also possible to use bootMonitor (instead of the board firmware) as the initial loader. It downloads the ChorusOS system image from a local device or from the network. See the ChorusOS 5.0 Installation Guide.

The bootMonitor utility is implemented as an application on top of a minimal ChorusOS configuration.