1. A multiprocessor computer system, comprising: a plurality of processors; a plurality of storage system adapters coupled to a storage system; a plurality of network adapters coupled to a network; and a memory storing a plurality of operating systems each of which is executed using a subset of the plurality of processors, and wherein each of the plurality of processors, storage system adapters and network adapters are assigned to one of the plurality of operating systems, the operating systems specify at least one of the plurality of processors assigned to the operating systems that are in a low load condition and maintain the specified processors idle, the plurality of operating systems share information indicating a current load of each of the plurality of processors, the plurality of storage system adapters, and the plurality of the network adapters, each operating system to which at least one idle processor is assigned activates one of its idle processors when the average load of its active processors increases and activates one of its idle processors when the load of its storage adapters and the load of its network adapters do not exceed their maximum, and one of the plurality of the operating systems reassigns to itself one of the plurality of processors that is idle and assigned to another operating system when the load of the processors assigned to the one operating system increases.