Magma EB7R-x8, EBU, EB7-x8 user manual

2.Most computers allow multiple logical bridges (and thus PCIe buses) to be correctly configured. Some computers, unfortunately, place an arbitrary limit on the number of bridge levels that can be traveled during power-on configuration. Your computer “power-on-software” should be compliant with the PCIe bus specification 1.1 in order to effectively use a Magma PCIe Expansion System. For "fan-out" and "daisy chained" system configurations, where more than one PCIe expansion system is being used, you should count all of the logical bridge levels to your most deeply nested PCI bus to determine the maximum number of bridge levels that must be traveled. Exceeding this number may cause software configuration conflicts even though hardware-wise the PCIe system is properly configured.

3.For easier understanding, a given PCI system should be viewed as a “Resource Toll road” that runs from the computer CPU (resource home), through the “Toll Booths” (the PCIe switches and logical PCI bridges), to the “Resource Users” (PCIe Cards). As in the case of a real Toll Road, the more Toll Booths you have to cross (even if it takes a nanosecond), the longer it will take you (your data) to get from the PCIe Card to the CPU and back again. Under most circumstances the effect cannot even be detected. However, under other conditions, it can be important to know about.

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