In the first case, “having it” usually means that it has an older, pre- ES set of software for MRP II. Perhaps the company took an earlier stab at implementing the resource planning processes—master scheduling, MRP, Plant and Supplier Scheduling, etc.—but didn’t succeed. Or possibly it never attempted to do so. In either case, it has software. Now the people might not like it; they might be saying things like, “Our software stinks.” But the odds are quite high that it’ll be good enough to enable the basic ERP processes to work. The moral of this story: use what you have if it’s workable. An excellent resource here is the MRP II Standard System, which details the features and functions that software must contain to support effective resource planning processes. As of this writing, this document is available via the Gray Research web site listed in Appendix D.