This IBM® Redbook describes how z/OS V1 DFSMS Transactional VSAM Services (DFSMStvs) works, how and when you might use it, and what you need to consider in your plans. This book should be of interest to you if you want to understand how you can increase the service hours of a CICS/VSAM system by reducing or eliminating the batch window, or if you want to run multiple concurrent batch jobs updating common VSAM data sets. This book is written for readers who have some knowledge of CICS®, VSAM, and VSAM Record Level Sharing, and who wish to understand more about DFSMStvs.