FIFO (computing and electronics)

FIFO is an acronym for first in, first out, a method for organizing and manipulating a data buffer, where the oldest (first) entry, or 'head' of the queue, is processed first. It is analogous to processing a queue with first-come, first-served (FCFS) behaviour: where the people leave the queue in the order in which they arrive.

FCFS is also the jargon term for the FIFO operating system scheduling algorithm, which gives every process central processing unit (CPU) time in the order in which it is demanded.

FIFO's opposite is LIFO, last-in-first-out, where the youngest entry or 'top of the stack' is processed first.

A priority queue is neither FIFO or LIFO but may adopt similar behaviour temporarily or by default.

Queueing theory encompasses these methods for processing data structures, as well as interactions between strict-FIFO queues.

Computer science

Data structure

Depending on the application, a FIFO could be implemented as a hardware shift register, or using different memory structures, typically a circular buffer or a kind of List. For information on the abstract data structure, see Queue (data structure).

FIFO and LIFO accounting

FIFO and LIFO methods are accounting techniques used in managing inventory and financial matters involving the amount of money a company has tied up within inventory of produced goods, raw materials, parts, components, or feed stocks. These methods are used to manage assumptions of cost flows related to inventory, stock repurchases (if purchased at different prices), and various other accounting purposes.

FIFO

"FIFO" stands for first-in, first-out, meaning that the oldest inventory items are recorded as sold first but do not necessarily mean that the exact oldest physical object has been tracked and sold. In other words, the cost associated with the inventory that was purchased first is the cost expensed first. With FIFO, the cost of inventory reported on the balance sheet represents the cost of the inventory most recently purchased.

Consider this example: Foo Co. had the following inventory at hand, in order of acquisition in November:

If Foo Co. sells 210 units during November. The company would expense the cost associated with the first 100 units at $50 and the remaining 110 units at $55. Under FIFO, the total cost of sales for November would be $11,050. The ending inventory would be calculated the following way:

FIFO

FIFO is an acronym which most commonly stands for "first in, first out". Two common contexts for this are:

FIFO may also refer to:

See also