Aspects of the present invention include an N-Node virtual link trunking system comprising a set of N nodes collectively provide a logical fabric-level view that is consistent across the set of N nodes. Then, an actuator of each leg link is controlled to generate a force for the determined share. The apparatus comprises at least a vertical post, a latch member, and a gate. The requesting unit is configured to request an external device to identify the target object when the identification unit is not able to identify the target object. The memory module includes a plurality of dynamic random access memories and a fault storage unit. By the construction, at rolling of the rolling elements formed with a relatively hard ceramic material, the occurrence of the surface scratches of the rolling elements can be restrained, which results in restraining the vibrations and noises caused by the rolling bearing.