EIEIO
EIEIO is a four-letter sequence or acronym with multiple meanings. It may refer to:
- '''Enforce In-order Execution of I/O''', a PowerPC instruction (see [[Computing]])
- '''Enhanced Implementation of Emacs Interpreted Objects''', an Emacs library (see [[Computing]])
- "Computer bought the farm" error message in computing (see [[Computing]])
- The refrain "E-I-E-I-O" in the nursery rhyme "[[Old MacDonald Had a Farm]]" (see [[Media and entertainment]])
- "[[E-I-E-I-O (Bluey episode)|E-I-E-I-O]]", an episode of the Australian TV series ''Bluey'' (see [[Media and entertainment]])
Computing
Enforce In-order Execution of I/O (PowerPC instruction)
The Enforce In-Order Execution of I/O (EIEIO) is a synchronization instruction in the PowerPC architecture that ensures all preceding load and store operations to cache-inhibited storage complete in main memory before any subsequent load or store operations to such storage begin.[1][2] This mechanism prevents out-of-order execution that could lead to inconsistencies in I/O device interactions, treating EIEIO as a barrier in the storage access queue without altering data values, instruction fetch, or cache operations.[2][3] By flushing pending stores and serializing accesses to specific memory types—such as caching-inhibited, guarded, or write-through required—it guarantees that I/O devices observe storage references in the program-specified order.[1][2]
In assembly language, the instruction is encoded as eieio with no operands, using the X-form format (opcode 31, extended opcode 854).[2][3] It does not affect special registers like the Condition Register or Fixed-Point Exception Register and is ineffective on non-cache-inhibited memory.[1]
EIEIO was introduced as part of the core PowerPC User Instruction Set Architecture in the early 1990s, documented in the initial specification released in May 1994, and remains a standard feature in the Power ISA (e.g., Version 2.01 from 2003).[2][3] It is classified under optional facilities in some implementations but is widely supported across PowerPC variants.[3]
The instruction finds primary use in embedded systems for reliable I/O device communication and real-time data consistency, where it synchronizes accesses to memory-mapped peripherals.[3] In high-performance computing, EIEIO supports barrier synchronization in parallel environments to maintain memory ordering and prevent race conditions in shared I/O tasks.[3] EIEIO serves as a specialized memory barrier, distinct from broader synchronization primitives like sync, by focusing on I/O-specific ordering without full processor serialization.[1][2]
Enhanced Implementation of Emacs Interpreted Objects (Emacs library)
The Enhanced Implementation of Emacs Interpreted Objects (EIEIO) is a library that extends Emacs Lisp with object-oriented programming capabilities, including classes, methods, and inheritance mechanisms modeled after the Common Lisp Object System (CLOS).[4] It enables developers to build structured, reusable code for Emacs extensions by defining objects with slots for data storage and methods for behavior, while respecting Emacs Lisp's dynamic nature.[5] EIEIO serves as a foundational layer for more complex applications, such as integrated development environments, by providing type checking, slot accessors, and customization integration.[6]
Key features of EIEIO include support for multiple inheritance, allowing classes to derive from several superclasses; generic functions that permit method overloading based on argument types; and dynamic method dispatch, which selects the appropriate method at runtime similar to CLOS.[4] Additional Emacs-specific extensions encompass public and private slot classifications, integration with the Edebug debugger for stepping through object code, and byte-compilation support to optimize performance.[4] These elements facilitate conceptual organization in Lisp programming, where traditional functional paradigms can be augmented with object-oriented abstractions without requiring a full language redesign.[7]
EIEIO was developed by Eric Ludlam around 1995–1996 as an initial effort to introduce CLOS-like functionality to Emacs Lisp, addressing limitations in method dispatch and object persistence within the editor's scripting environment.[7] It originated as part of the Semantic project, a code parsing and analysis toolset within the broader Collection of Emacs Development Environment Tools (CEDET) suite, aimed at enhancing Emacs for software development tasks like syntax highlighting and code navigation.[8] Ludlam's work focused on creating a compatible subset of CLOS features tailored to Emacs Lisp constraints, such as lack of native multiple dispatch, while adding utilities like class browsers and a test suite.[6]
EIEIO became bundled with GNU Emacs starting in version 23.2 (released in 2010), integrating seamlessly into the core distribution to support advanced programming workflows. Within CEDET, it underpins tools for code analysis, such as Semantic's tag parsing and completion systems, enabling object-oriented modeling of source code structures across languages like C++ and Java.[9] This integration has made EIEIO a standard component for Emacs package authors seeking maintainable, extensible designs.
To define a class in EIEIO, the defclass macro is used, specifying the class name, superclasses (if any), and slot descriptors with options for initialization, type validation, and documentation. For example:
elisp
(defclass my-class ()
((my-slot :initarg :my-slot
:initform nil
:type [symbol](/page/Symbol)
:documentation "An example slot for storing a symbol."))
"A simple example class demonstrating EIEIO syntax.")
(defclass my-class ()
((my-slot :initarg :my-slot
:initform nil
:type [symbol](/page/Symbol)
:documentation "An example slot for storing a symbol."))
"A simple example class demonstrating EIEIO syntax.")
This creates a class my-class with a single slot my-slot, which can be initialized during object creation via (make-instance 'my-class :my-slot 'value).[4]
Methods are defined using defmethod (or cl-defmethod for compatibility), allowing specialization on class types for polymorphic implementation. A basic example might define a display method:
elisp
(cl-defmethod display ((obj my-class))
"Display the contents of the object."
(format "My class instance with slot: %s" (oref obj my-slot)))
(cl-defmethod display ((obj my-class))
"Display the contents of the object."
(format "My class instance with slot: %s" (oref obj my-slot)))
Calling (display (make-instance 'my-class :my-slot 'example)) would output the slot's value, illustrating method dispatch on the object type.[4] These constructs support inheritance by specifying superclasses in defclass, enabling slot and method reuse across class hierarchies.[4]
"Computer bought the farm" error message
The "Computer bought the farm" error message, associated with the error code EIEIO, originates from the GNU Hurd operating system, a microkernel-based project developed as part of the GNU initiative starting in 1990.[10] In this context, EIEIO serves as a symbolic error code for various "hopeless" or unrecoverable system failures, such as when a translator—a server providing filesystem or device functionality—crashes during access attempts, rendering the operation impossible to complete.[10] The code is defined in the system's errno.h header with the value 0x40000068, explicitly mapping to the humorous message "Computer bought the farm" to indicate a fatal crash.
The phrase "bought the farm" itself is a mid-20th-century American military idiom, particularly from aviation slang during World War II and the Korean War, referring to a pilot's death in a crash where life insurance payouts would settle debts like a farm mortgage, allowing the family to "buy the farm" outright.[11] In GNU Hurd, developers adapted this idiom playfully to denote computer system death, punning on the nursery rhyme "Old MacDonald Had a Farm" with its refrain "E-I-E-I-O" to create the acronym EIEIO, adding levity to otherwise dire error reporting.[10] This choice reflects the GNU project's culture of whimsical yet informative diagnostics, similar to other error messages like "lp0 on fire" in Linux for printer issues.
Historically, EIEIO emerged in the early 1990s during GNU Hurd's development by the Free Software Foundation, where it was integrated into the error-handling framework to signal irreparable faults without technical jargon, aiding users in niche research and experimental environments.[10] While not tied to specific memory or I/O handling, it often appears in scenarios involving failed inter-process communication or server breakdowns in Hurd's distributed architecture.[10]
In contemporary systems, EIEIO remains a remnant primarily in GNU Hurd and the GNU C Library (glibc) documentation, where it is preserved for compatibility and humor, though Hurd's limited adoption means encounters are rare outside legacy or hobbyist setups. References to it persist in open-source discussions and codebases, serving as a cultural nod to early free software engineering quirks, but it has no active role in mainstream operating systems like Linux or BSD.[12]
Refrain in "Old MacDonald Had a Farm"
The refrain "E-I-E-I-O" in the nursery rhyme "Old MacDonald Had a Farm" serves as a phonetic spelling of the vocalization "ee-eye-ee-eye-oh," functioning as a catchy, repetitive chorus that follows each verse describing farm animals and their sounds.[13] This nonsense syllable sequence provides rhythmic structure to the song, appearing after lines like "With a moo-moo here and a moo-moo there, here a moo, there a moo, everywhere a moo-moo," before transitioning to the next animal.[14] The refrain's repetition reinforces the cumulative format, allowing children to participate easily while learning animal noises such as quacks, oinks, or neighs.[13]
The song's historical roots trace back to a 1706 English opera titled The Kingdom of the Birds (also known as Wonders in the Sun), composed by Thomas d'Urfey, where an early variant called "In the Fields in Frost and Snow" or "A Charming Country Life" featured similar farm-themed lyrics with repetitive choruses, though without the exact "E-I-E-I-O" phrasing.[13] These elements evolved through British folk traditions before the modern American version emerged in the early 20th century, with sheet music first published in 1917 in Lieutenant F. T. Nettleingham's songbook Tommy's Tunes, which included lyrics closer to the contemporary form and helped popularize the refrain among schoolchildren.[13] The syllables have no definitive meaning, interpreted instead as a mnemonic device or onomatopoeic filler to enhance the song's musicality and memorability.[14]
Culturally, "E-I-E-I-O" holds significant educational value, taught globally in early childhood programs to develop phonemic awareness, vocabulary for animal sounds, and rhythmic patterns in language learning.[13] Its universal appeal stems from the song's simplicity, making it a staple in preschool curricula and multicultural settings for fostering interactive singing. Regional variations exist in spelling and pronunciation, such as the British "Ee-aye-ee-aye-oh" compared to the American "E-I-E-I-O," reflecting phonetic adaptations in oral traditions.[15] The refrain has been adapted in media, including Disney Junior's animated versions featuring Mickey Mouse and educational videos like Baby Einstein's farm-themed episodes, which incorporate it to engage young viewers with visuals of animals and sounds.[16]
"E-I-E-I-O" (Bluey episode)
"Old MacDonald" is a minisode of the Australian animated children's television series Bluey, created by Joe Brumm. It originally premiered on ABC Kids in Australia on May 20, 2021, and was re-aired internationally on Disney+ and ABC iview in October 2025 as part of the Bluey Minisodes collection. Written by Brumm, the minisode runs for approximately 1.5 minutes and features the voice talents of David McCormack as Bandit, Melanie Zanetti as Chilli, and the young actors portraying Bluey and Bingo.[17]
The minisode follows the Heeler family playing a game of "Old MacDonald" in the backyard, where Chilli names a farm animal for the others to imitate with sounds and actions: Bingo as a pig, Bandit as a cow, Bluey as a chicken, and finally Chilli as a horse. The narrative incorporates farm animal sounds directly referencing the refrain of the nursery rhyme "Old MacDonald Had a Farm," weaving the song's structure into the gameplay for added interactivity.[18]
Thematically, "Old MacDonald" delves into creativity and family bonding through unstructured play, illustrating how children like Bluey and Bingo use games to explore imagination and encourage participation from parents. It highlights the joy of role-playing and animal mimicry in building relationships, with the farm setting serving as a simple backdrop for these interactions. The minisode connects to broader cultural elements by directly nodding to the nursery rhyme's refrain in its title and content, adapting traditional children's songs into modern storytelling to promote imaginative expression.
Critics and viewers praised the minisode for its relatable humor, capturing the spontaneity of family playtime and the charm of animal mimicry, which resonated with parents and children alike. As part of Bluey's minisodes and ongoing content, it contributes to the series' acclaim, including the 2023 Kidscreen Award for Best Animated Series and the International Emmy for Kids: Series in prior seasons, underscoring its role in the show's high-impact contributions to children's programming.[19]