SpaceCalc by ASPG is designed to improve storage efficiency through file modeling and allocation. It proactively calculates the efficient amount of space needed for VSAM files before any allocations are performed. SpaceCalc supports all current DASD devices and releases of z/OS, and it is compatible with existing files to determine if they are operating efficiently. It provides full technical support for IBM’s DFSMS, including SMS calculations and placement of VSAM files. SpaceCalc allows storage administrators to run what-if simulations to optimize space utilization before making allocations, which can then be performed directly from SpaceCalc. It eliminates guesswork in calculating space allocations, providing an efficient solution for maximizing system facilities. SpaceCalc is ideal for large enterprise systems where space allocation is complex and time-consuming, offering fast, accurate allocations and complex VSAM modeling. Its TSO/ISPF panel-driven interactive design is user-friendly and quick to learn, making it a useful tool for teaching storage administrators the importance of proper external storage and VSAM.