Supporting FIFO FIFO is an acronym for first in, first out, a method for organizing the manipulation of a data structure where the oldest entry, or "head" of the queue, is processed first. (First In, First Out) behavior for Entries is a critical requirement when building messaging systems or implementing master-worker patterns. Users should be able to get Entries in the same order in which they were written. GigaSpaces supports both non-ordered Entries and FIFO-ordered Entries when performing Space Where GigaSpaces data is stored. It is the logical cache that holds data objects in memory and might also hold them in layered in tiering. Data is hosted from multiple SoRs, consolidated as a unified data model. operations.