A software-based controller implemented on a generic computer hardware platform for dynamically allocating and controlling multiple job streams for anumerically controlling a machine tool. The software-based controller includes a first module for performing a set of first operations corresponding to a first job stream, a second module for performing a set of second operations corresponding to said first job stream, and a third module for performing a set of third operations corresponding to a second job stream. Each of the first, second and third modules are collectively defining a pointer architecture that includes a vertical data system to facilitate communication between operations in the same job stream and a horizontal data system to facilitate communication between operations in different job streams. A shared memory accessible to the first, second and third modules is further defined as having a vertical data structure associated with said vertical data system and a horizontal data structure associated with said horizontal data system. The first, second and third modules communicating through the shared memory by: (a) using the vertical data system to point operations in a common job stream to a first common shared memory location in said vertical data structure; and (b) using the horizontal data system to point operations in a different job streams to a second common shared memory location in said horizontal data structure.