Patent ID: 8769159

Claim:
A non-transitory computer-readable memory medium storing program instructions executable by a host computer to: prior to the startup of the host computer, store information indicating resource requirements of an external device, wherein the external device comprises one or more of: an external chassis having a plurality of slots for installing modules; or a controller device for the external chassis; and enable a variable power-on feature for the external device in response to user input requesting the variable power-on feature to be enabled; at a startup of the host computer, access the information to determine a plurality of resources to reserve for the external device, and reserve the plurality of resources for the external device based on said enabling, wherein the external device is not available at the startup of the host computer because the external device is not powered on during the startup of the host computer, and wherein the external device is configured to be coupled to an expansion bus of the host computer; detect that the external device becomes available subsequently to reserving the plurality of resources, wherein said detecting that the external device becomes available comprises detecting that the device becomes powered on; and enable the external device to use the plurality of resources that were previously reserved at the startup of the host computer, wherein enabling the device to use the plurality of resources configures the device to operate on the expansion bus.