Abstract: An improved internal reader function is disclosed in which all internal reader jobs are dynamically created (and scheduled) and canceled. The operator no longer needs to guess how many internal readers to create and cancel in order to handle the ever-changing computer system workload. Instead, a subsystem of the computer system operating system continuously and optimally handles the workload by automatically creating new internal reader jobs or assigning work to previously automatically created internal reader jobs which have completed processing and are waiting for additional work, i.e. data sets, to be processed. To handle this dynamic processing, a control block structure is created to keep track of the internal reader jobs. The improved subsystem also eliminates "Bottlenecks" since all data sets to be processed are transferred directly to an internal reader job data set control block.