A hardware bug is a defect in the design, manufacture, or operation of

computer hardware Computer hardware includes the physical parts of a computer, such as the case, central processing unit (CPU), random access memory (RAM), monitor, mouse, keyboard, computer data storage, graphics card, sound card, speakers and motherboard. ...

that causes incorrect operation. It is the counterpart of

software bugs A software bug is an error, flaw or fault in the design, development, or operation of computer software that causes it to produce an incorrect or unexpected result, or to behave in unintended ways. The process of finding and correcting bugs i ...

which refer to flaws in the code which operates computers, and is the original context in which " bug" was used to refer to such flaws. Intermediate between hardware and software are

microcode In processor design, microcode (μcode) is a technique that interposes a layer of computer organization between the central processing unit (CPU) hardware and the programmer-visible instruction set architecture of a computer. Microcode is a la ...

and

firmware In computing, firmware is a specific class of computer software that provides the low-level control for a device's specific hardware. Firmware, such as the BIOS of a personal computer, may contain basic functions of a device, and may provide h ...

which may also have such defects. In common usage, a bug is subtly different from a "

glitch A glitch is a short-lived fault in a system, such as a transient fault that corrects itself, making it difficult to troubleshoot. The term is particularly common in the computing and electronics industries, in circuit bending, as well as among ...

" which may be more transient than fundamental, and somewhat different from a "quirk" which may be considered useful or intrinsic.

Errata An erratum or corrigendum (plurals: errata, corrigenda) (comes from la, errata corrige) is a correction of a published text. As a general rule, publishers issue an erratum for a production error (i.e., an error introduced during the publishing pro ...

(corrections to the documentation) may be published by the manufacturer to reflect such unintended operation, and "errata" is sometimes used as a term for the flaws themselves.

History

The Middle English word ''

bugge Bugge is a Norwegian surname and may refer to: People * Bugge Wesseltoft (born 1964), Norwegian jazz musician * David Buggé (born 1956), English cricketer and banker * Peder Olivarius Bugge (1764–1849), Norwegian bishop * Sophus Bugge (1833� ...

'' is the basis for the terms "

bugbear A bugbear is a legendary creature or type of hobgoblin comparable to the boogeyman (or bugaboo or babau or cucuy), and other creatures of folklore, all of which were historically used in some cultures to frighten disobedient children. Etymology ...

" and " bugaboo" as terms used for a monster. The term "bug" to describe defects has been a part of engineering jargon since the 1870s and predates electronic computers and computer software; it may have originally been used in hardware engineering to describe mechanical malfunctions. For instance,

Thomas Edison Thomas Alva Edison (February 11, 1847October 18, 1931) was an American inventor and businessman. He developed many devices in fields such as electric power generation, mass communication, sound recording, and motion pictures. These inventi ...

wrote the following words in a letter to an associate in 1878:

Baffle Ball ''Baffle Ball'' is a pinball machine created in November 19, 1931 by David Gottlieb, founder of the Gottlieb amusement company. Gameplay For one US cent players get ten balls. These balls are fired up onto the playfield and fall into pockets and ...

, the first mechanical

pinball Pinball games are a family of games in which a ball is propelled into a specially designed table where it bounces off various obstacles, scoring points either en route or when it comes to rest. Historically the board was studded with nails call ...

game, was advertised as being "free of bugs" in 1931. Problems with military gear during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

were referred to as bugs (or

es). In the 1940 film, ''

Flight Command ''Flight Command'' is a 1940 American film about a cocky U.S. Navy pilot who has problems with his new squadron and with the wife of his commander. It stars Robert Taylor, Ruth Hussey and Walter Pidgeon. ''Flight Command'' has the distinction of ...

'', a defect in a piece of direction-finding gear is called a "bug". In a book published in 1942, Louise Dickinson Rich, speaking of a powered

ice cutting Ice cutting is a winter task of collecting surface ice from lakes and rivers for storage in ice houses and use or sale as a cooling method. Rare today, it was common (see ice trade) before the era of widespread mechanical refrigeration and air c ...

machine, said, "Ice sawing was suspended until the creator could be brought in to take the bugs out of his darling."

Isaac Asimov yi, יצחק אזימאװ , birth_date = , birth_place = Petrovichi, Russian SFSR , spouse = , relatives = , children = 2 , death_date = , death_place = Manhattan, New York City, U.S. , nationality = Russian (1920–1922)Soviet (192 ...

used the term "bug" to relate to issues with a robot in his short story "

Catch That Rabbit "Catch that Rabbit" is a science fiction short story by American writer Isaac Asimov. It was first published in the February 1944 issue of ''Astounding Science Fiction'' and reprinted in the collections ''I, Robot'' (1950) and '' The Complete R ...

", published in 1944. First Computer Bug, 1945

The term "bug" was used in an account by computer pioneer

Grace Hopper Grace Brewster Hopper (; December 9, 1906 – January 1, 1992) was an American computer scientist, mathematician, and United States Navy rear admiral. One of the first programmers of the Harvard Mark I computer, she was a pioneer of compu ...

, who publicized the cause of a malfunction in an early electromechanical computer. A typical version of the story is: Hopper did not find the bug, as she readily acknowledged. The date in the log book was September 9, 1947.Log Book With Computer Bug
", National Museum of American History, Smithsonian Institution. The operators who found it, including William "Bill" Burke, later of the

Naval Weapons Laboratory The United States Naval Surface Warfare Center Dahlgren Division (NSWCDD), named for Rear Admiral John A. Dahlgren, is located in King George County, Virginia, in close proximity to the largest fleet concentration area in the Navy. NSWCDD is ...

Dahlgren, Virginia Dahlgren is an unincorporated community and census-designated place (CDP) in King George County, Virginia, United States. The population was 2,946 at the time of the 2020 census, up from 2,653 at the 2010 census, and up from 997 in 2000. History ...

, were familiar with the engineering term and amusedly kept the insect with the notation "First actual case of bug being found." Hopper loved to recount the story. This log book, complete with attached moth, is part of the collection of the Smithsonian

National Museum of American History The National Museum of American History: Kenneth E. Behring Center collects, preserves, and displays the heritage of the United States in the areas of social, political, cultural, scientific, and military history. Among the items on display is t ...

Unintended operation

Sometimes users take advantage of the unintended or undocumented operation of hardware to serve some purpose, in which case a flaw may be considered a feature. This gives rise to the often ironically employed acronym INABIAF, "It's Not A Bug It's A Feature". For example, undocumented instructions, known as illegal opcodes, on the MOS Technology 6510 of the

Commodore 64 The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness W ...

and

MOS Technology 6502 The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit microprocessor that was designed by a small te ...

of the

Apple II The Apple II (stylized as ) is an 8-bit home computer and one of the world's first highly successful mass-produced microcomputer products. It was designed primarily by Steve Wozniak; Jerry Manock developed the design of Apple II's foam-m ...

computers are sometimes utilized. Similarly programmers (notably

game A game is a structured form of play, usually undertaken for entertainment or fun, and sometimes used as an educational tool. Many games are also considered to be work (such as professional players of spectator sports or games) or art (suc ...

and demo) on the

Commodore Amiga Amiga is a family of personal computers introduced by Commodore in 1985. The original model is one of a number of mid-1980s computers with 16- or 32-bit processors, 256 KB or more of RAM, mouse-based GUIs, and significantly improved graphi ...

took advantage of the unintended operation of its coprocessors to produce new effects or optimizations.

Security vulnerabilities

Some flaws in hardware may lead to security vulnerabilities where

memory protection Memory protection is a way to control memory access rights on a computer, and is a part of most modern instruction set architectures and operating systems. The main purpose of memory protection is to prevent a process from accessing memory that h ...

or other features fail to work properly. Starting in 2017 a series of security vulnerabilities were found in the implementations of

speculative execution Speculative execution is an optimization technique where a computer system performs some task that may not be needed. Work is done before it is known whether it is actually needed, so as to prevent a delay that would have to be incurred by doing ...

on common processor architectures that allowed a violation of

privilege level In computer science, hierarchical protection domains, often called protection rings, are mechanisms to protect data and functionality from faults (by improving fault tolerance) and malicious behavior (by providing computer security). Computer ...

. In 2019 researchers discovered that a manufacturer debugging mode, known as VISA, had an undocumented feature on

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 ser ...

Platform Controller Hubs, known as chipsets, which made the mode accessible with a normal motherboard possibly leading to a security vulnerability.

Pentium bugs

The Intel

Pentium Pentium is a brand used for a series of x86 architecture-compatible microprocessors produced by Intel. The original Pentium processor from which the brand took its name was first released on March 22, 1993. After that, the Pentium II and P ...

series of CPUs had two well-known bugs discovered after it was brought to market, the FDIV bug affecting floating point division which resulted in a recall in 1994, and the F00F bug discovered in 1997 which causes the processor to stop operating until rebooted.

References

{{reflist Hardware bugs Engineering concepts

History

Unintended operation

Security vulnerabilities

Pentium bugs

See also

References