3. The system of claim 1 wherein said means for generating revised JCL statements generates revised JCL statements requesting allocation of data storage space for each dataset in predetermined data storage areas grouped by predetermined ranges of size.
1. A system for modifying job control language (JCL) statements to optimize data storage allocations for datasets comprising: data collection means for collecting historical data concerning actual data storage space requirements of each dataset; parsing means for parsing JCL statements for references to datasets and requested data storage space allocations; and means for generating revised JCL statements containing revised requests for data storage space allocations for said datasets based on said historical data.