(1) A system for keeping track of the order in which information or materials are to be processed. The goal of FIFO is to prevent earlier orders from being delayed in favor of newer orders which would result in increased lead time and unhappy customers regarding the earlier orders. Use of material produced by one process in the same order by the next process. A FIFO queue is filled by the supplying process and emptied by the customer process. When a FIFO lane gets full, production is stopped until the next (internal) customer has used some of that inventory.
(2) A work controlled method to ensure the oldest work upstream (first in) is the first to be processed downstream (first out).