In computing and in systems theory , first in, first out (the first in is the first out), acronymized as FIFO , is a method for organizing the manipulation of a data structure (often, specifically a data buffer ) where the oldest (first) entry, or "head" of the queue , is processed first.
15-567: [REDACTED] Look up lilo or LILO in Wiktionary, the free dictionary. Lilo or LILO may refer to: People [ edit ] Lilo (name) , a list of people with the nickname or surname Lilo (footballer) , Brazilian footballer Murilo Rufino Barbosa (born 1983) Lilo (actress) , stage name of German-born French actress and singer Liselotte Johanna Lewin (1921-2022) LILO [ edit ] LILO (boot loader) , Linux loader,
30-414: A Gray code (or any unit distance code) for the read and write pointers to ensure reliable flag generation. One further note concerning flag generation is that one must necessarily use pointer arithmetic to generate flags for asynchronous FIFO implementations. Conversely, one may use either a leaky bucket approach or pointer arithmetic to generate flags in synchronous FIFO implementations. A hardware FIFO
45-402: 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) . Most software implementations of a FIFO queue are not thread safe and require a locking mechanism to verify the data structure chain is being manipulated by only one thread at
60-507: A FIFO is another name for a named pipe . Disk controllers can use the FIFO as a disk scheduling algorithm to determine the order in which to service disk I/O requests, where it is also known by the same FCFS initialism as for CPU scheduling mentioned before. Communication network bridges , switches and routers used in computer networks use FIFOs to hold data packets in route to their next destination. Typically at least one FIFO structure
75-503: A dual-port SRAM is usually used, where one port is dedicated to writing and the other to reading. The first known FIFO implemented in electronics was by Peter Alfke in 1969 at Fairchild Semiconductor . Alfke was later a director at Xilinx . A synchronous FIFO is a FIFO where the same clock is used for both reading and writing. An asynchronous FIFO uses different clocks for reading and writing and they can introduce metastability issues. A common implementation of an asynchronous FIFO uses
90-448: A piece of low-level software Last in, last out , or first in, first out in queues Left-in/left-out , a roadway intersection Linzer Lokalbahn , a railway line in upper austria going from and to Linz. Other uses [ edit ] Lilo Pelekai , a titular character in the 2002 Disney film Lilo & Stitch and its franchise Air mattress or lilo, from the trademark Li-Lo See also [ edit ] Didi Lilo ,
105-448: A piece of low-level software Last in, last out , or first in, first out in queues Left-in/left-out , a roadway intersection Linzer Lokalbahn , a railway line in upper austria going from and to Linz. Other uses [ edit ] Lilo Pelekai , a titular character in the 2002 Disney film Lilo & Stitch and its franchise Air mattress or lilo, from the trademark Li-Lo See also [ edit ] Didi Lilo ,
120-458: A time. The following code shows a linked list FIFO C++ language implementation. In practice, a number of list implementations exist, including popular Unix systems C sys/queue.h macros or the C++ standard library std::list template, avoiding the need for implementing the data structure from scratch. In computing environments that support the pipes-and-filters model for interprocess communication ,
135-534: A village near Tbilisi, Georgia Lillo (disambiguation) Liloy , Zamboanga del Norte, Philippines Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Lilo . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Lilo&oldid=1231315392 " Category : Disambiguation pages Hidden categories: Short description
150-534: A village near Tbilisi, Georgia Lillo (disambiguation) Liloy , Zamboanga del Norte, Philippines Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Lilo . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Lilo&oldid=1231315392 " Category : Disambiguation pages Hidden categories: Short description
165-629: Is different from Wikidata All article disambiguation pages All disambiguation pages lilo [REDACTED] Look up lilo or LILO in Wiktionary, the free dictionary. Lilo or LILO may refer to: People [ edit ] Lilo (name) , a list of people with the nickname or surname Lilo (footballer) , Brazilian footballer Murilo Rufino Barbosa (born 1983) Lilo (actress) , stage name of German-born French actress and singer Liselotte Johanna Lewin (1921-2022) LILO [ edit ] LILO (boot loader) , Linux loader,
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#1732844367791180-460: Is different from Wikidata All article disambiguation pages All disambiguation pages Last in, last out Such processing is analogous to servicing people in a queue area on a first-come, first-served (FCFS) basis, i.e. in the same sequence in which they arrive at the queue's tail. FCFS is also the jargon term for the FIFO operating system scheduling algorithm, which gives every process central processing unit (CPU) time in
195-412: Is used for synchronization purposes. It is often implemented as a circular queue , and thus has two pointers : Examples of FIFO status flags include: full, empty, almost full, and almost empty. A FIFO is empty when the read address register reaches the write address register. A FIFO is full when the write address register reaches the read address register. Read and write addresses are initially both at
210-517: Is used per network connection. Some devices feature multiple FIFOs for simultaneously and independently queuing different types of information. FIFOs are commonly used in electronic circuits for buffering and flow control between hardware and software. In its hardware form, a FIFO primarily consists of a set of read and write pointers , storage and control logic. Storage may be static random access memory (SRAM), flip-flops , latches or any other suitable form of storage. For FIFOs of non-trivial size,
225-413: 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. Depending on the application,
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