It's a Wal-Mart executive's dream: an inventory system that knows just how many cans of chicken soup are sitting on the shelves and provides a real-time picture of when they arrive from the factory and depart in shoppers' baskets. The first field test of such a system is about to begin.

The likely test bed: a retail warehouse in Tulsa, OK. The technology: tiny versions of the toll-paying "radio tags" found on many car windshields. This October, researchers from MIT's Auto-ID Center will affix these tags to forklift-sized pallets of products. Tag readers on warehouse shelves will log the movements of arriving and departing pallets; this information will be relayed via the Internet to retail headquarters and manufacturers (see "Beyond the Bar Code," TR March 2001).