Wal-Mart has used radio frequency identification tags (RFID), which use numerical codes that can be scanned from a distance to track pallets of merchandise moving along the supply chain. Even more recently the company has begun using smart tags, read by a handheld scanner, that allow employees to quickly learn which items need to be replaced so that shelves are consistently stocked and inventory is closely watched.
RFID and smart tags are just the next generation in supply chain innovation that dates back to the 1960s, when Sam Walton personally attended an IBM school in upstate New York with the intention of landing experts to computerize operations.