Global Resource Serialization (GRS) is the component within the IBM z/OS operating system responsible for enabling fair access to serially reusable computing resources, such as datasets and tape drives or virtual resources, such as lists, queues, and control blocks.
The Global Resource Serialization (GRS) function in IBM z/OS ensures that multiple users have equal access to serially accessible computing assets like data sets and tape devices, or virtual resources such as queues and control blocks.