The Virtual Telecommunications Access Method: A Systems Network Architecture perspective

Even before the advent of the Systems Network Architecture, there were strong motivations for a new teleprocessing access method. The introduction of VTAM provided both sharing of network resources and direct control of communications. VTAM also represented an optimization for the recent enhancements in CPU technology, e.g., dynamic address translation and multiprocessing. In conjunction with the queued control capabilities of TCAM, VTAM formed a base for consolidation and further enhancement of IBM'S communications facilities.