Preventing interlocks

The greater the number of device reservations occurring in each sharing system, the greater the chance of interlocks occurring. Allowing each task to reserve only one device minimizes the exposure to interlock. The system cannot detect interlocks caused by a program's use of the RESERVE macro and therefore, enabled wait states can occur on the system. Global resource serialization can also be used to prevent interlocks by suppressing the hardware RESERVE or simply issuing a global ISGENQ to serialize the resource. See z/OS MVS Planning: Global Resource Serialization for additional information on this topic.