From the software perspective, the following steps occur when the system starts up:

  1. Processor begins executing at the reset vector. The Initial Program Loader (IPL) locates the OS image and transfers control to the startup program in the image.
  2. Startup program configures the system and transfers control to the microkernel and process manager (procnto).
  3. The procnto module loads additional drivers and application programs.

After we look at the software aspects in some more detail, we'll consider the impact that the hardware has on this startup process.