1. A computer program product for processing a start command in a computing environment comprising a coupling facility coupled to one or more processor images of the computing environment, the computer program product comprising: a non-transitory computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising: receiving by the coupling facility from a processor image coupled thereto a start operator message command, the start operator message command comprising a message command block including a message header, an indication of the start operator message command, an operator message request that includes an operator message command to be processed by the coupling facility, an operator message request length and an operator message token; based on receiving the start operator message command, processing the start operator message command, wherein the processing comprises: storing within a selected buffer of one or more buffers the operator message token, the operator message request and the operator message request length, wherein the operator message token uniquely identifies the operator message command and associates the selected buffer with the operator message command; setting within the selected buffer a timer to current time; setting a state of the selected buffer; and providing a response code for the start operator message command.