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3.1.3 Number of CPUs and Number of Root Complexes

3.1.3 Number of CPUs and Number of Root Complexes
A root complex consists of an I/O controller mounted on a processor and the PCI switches, PCI devices, etc. under the I/O controller.
For details, see "3.3  Relationship Between the CPU Configuration and the Number of Root Complexes."
The maximum number of each type of mounted PCI card and the available PCI slots vary depending on the number of root complexes. The number of root complexes of the SPARC M10-4S is as follows according to the CPU configuration.
  1. For a 2-CPU configuration, four root complexes
  2. For a 4-CPU configuration, four or seven root complexes
Note - For cases where a CPU module is installed after the installation of the equipment with a change from the 2-CPU configuration to the 4-CPU configuration, the recommended configuration is the one with four root complexes. This configuration inherits the I/O bus configuration and mounting rules of the 2-CPU configuration. Changing the configuration into one with seven root complexes increases the maximum number of mounted PCI cards. However, system reconfiguration is required because the I/O bus is reconfigured.