What is "fifo"

FIFO \FIFO\ (f[imac]"f[=o]), a. [acronym, First In First Out.] 1. (accounting) an accounting method in which goods in inventory are valued at the price of the most recent acquisition of each type of goods, and those used up from inventory are valued at the cost of those first acquired.

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.

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

• FIFO and LIFO accounting
• FIFO (computing and electronics), a method of queuing or memory management

FIFO may also refer to:

• Fit in or fuck off, an unofficial human resource expression used within organizations
• Fly-in fly-out, a human resources strategy for deployment of personnel to remote locations