The following occurs when DFSMShsm is doing recall mount optimization, which means that several recalls occur end to end while a tape is continuously mounted. Since this could go on for an indefinite length of time, DFSMShsm has the SETSYS option TAPERECALLLIMITS. TAPERECALLLIMITS provides a time value after which a tape can be taken away from recall by recall on another DFSMShsm host. The takeaway occurs only if the request on the other host is of higher priority than the request that would otherwise be performed without demounting the tape. The priority is typically based on time of arrival, but the priority can be changed by using the ARCRPEXT installation exit.