The computerization of book inventories in warehouses allowed houses to keep
relatively accurate records of damaged books (which often occurs when warehouse
fork lifts inadvertently cut into cartons or plastic covered skids), normal errors due
to the miscoding of cartons or skids, and "shrinkage" (i.e., the disappearance of
books). Business operations also handle the processing and fulfillment of a book
order (e.g., 12 copies of a paperback version of Hamlet are requested by a bookstore
in Upland, California). The order is processed to ascertain the title's correct ISBN
number (the International Standard Book Number; each book, whether hardcover
or paperback, has a unique identification number that can be found on the back outside
cover), whether it is in print (if not the invoice is labeled "OP," out of print),
temporarily out of print ("TOP"), in stock (if not, "OS"), temporarily out of stock,