Discussed is work toward satisfying requirements on the Conversational Monitor System (CMS) in the areas of data sharing and physical DASD space sharing. This work advances the present CMS file system design that allows only active read sharing among users on a single VM system, where each user has a reserved, private allocation of DASD space for file data. Described in this paper is the CMS Shared File System (SFS), which was designed to satisfy the data sharing and physical DASD space sharing requirements by providing a pool of DASD space that is shared among multiple users. DASD space assigned to the pool is easily extended, and read/write sharing of individual files is allowed. Also discussed is SFS security, usage of Virtual Machine/Enterprise Systems Architecture (VM/ESA) data spaces for single system performance, and coordinated resource recovery to provide file data integrity in the distributed environment.