First in - first out

from Wikipedia, the free encyclopedia

First In - First Out ( English for one after the other ), often abbreviated to FIFO , synonymous with " First come, first served. Or FCFS ( first come, first served ), refers to any method of storage in which the elements that were saved first are also removed from the memory first. Such a data structure is also known as a (waiting) queue . Other principles are the " Last In - First Out " method (LIFO, stack ), the " Highest In - First Out " method (HIFO), in which the element with the highest value is removed first and the " Lowest " In - First Out “procedure (LOFO), in which the least significant element is taken first.

In accounting, there are also two other types of sequential consumption procedures , namely KIFO ( Group In - First Out ) and KILO ( Group In - Last Out ). They state that the items acquired by the group company are consumed or sold first or last.

Merchandise management

In the area of merchandise management , FIFO is the usual procedure, since - from the point of view of the end of the period - the oldest (first stored) stocks should be used first, if possible. When storing bulk goods , the FIFO principle is also fulfilled by a silo . Goods with a best- before date or an expiry date are generally outsourced using the FEFO (First Expired - First Out) procedure . For non-perishable bulk goods, on the other hand, the more cost-effective storage in heaps is used, which can only be removed from above, i.e. are considered according to the LIFO method. The difference between the two methods is particularly relevant for inventory valuation . Under commercial law, both the FIFO and the LIFO method are permitted for accounting ( Section 256 Sentence 1 HGB ). However, since only LIFO may be applied under tax law ( Section 6 (1) No. 2a EStG ), this procedure is more widespread in practice.

A distinction is made between company accounting and inventory management. Here FIFO means the booking of goods receipts at historical costs and the assessment of the stock value not according to average costs (average costs × old inventory + actual costs × additional inventory / total inventory), but according to the actual costs of the oldest unused goods receipt.

Computer science

FIFO representation

In computer science , first in - first out describes a special way of storing and retrieving data. The queue in computer science is based on the FIFO principle. Items are retrieved in the exact order in which they were previously placed. At the level of the operating system , data connections that are organized according to the FIFO principle are called pipes .

A practical area in computer science in which a FIFO is used are controllers, especially the serial interface (RS232 port) on PCs. The buffered chip uses a FIFO method to ensure that the first byte arriving at the serial interface is processed first by software in the computer. Byte protocols (such as by a mouse) remain linearly equivalent for “readers” (drivers) and “writers” (mouse). This also applies to the keyboard buffer .

Production engineering

Dependencies on multiple processes

In production engineering / production control , FIFO is used to link two processes . Linking here means that the follow-up process controls the previous process without the need for any ERP ( Enterprise Resource Planning ) tools . The background is, as already mentioned in the definition, that the goods that are first stored in the infeed are also consumed first.

However, the goods are only stored for a short period of time. As a rule, the security of supply of the subsequent processes is ensured so that they do not suffer a standstill. This system is used when the delivery process has faster cycle times than the follow-up process and these cannot be linked directly to one another, or when the delivery process is required for several products.

See also

Individual evidence

  1. Dictionary entry on first in - first out
  2. Dictionary entry on First come, first served.
  3. Nikolaus Wulff: Introduction to Computer Science I. Accessed on December 19, 2015 .