aspects for read / write data sharing of dasd data in a cluster of multiple data processing systems are described . in a method aspect , the method includes utilizing a first system as a managing system for file data modification of at least one file system , the at least one file system including a byte file system . the method further includes controlling access by at least one second system within the cluster of multiple system to data of the at least one file system through global token management , wherein concurrent , direct dasd read / write sharing of data of the at least one file system across the cluster of multiple systems occurs .