title: 2003 invasion of Iraq

text: Critics within this vein have further argued that containment would have been an effective strategy for the Saddam government, and that the top U.S. priorities in the Middle East should be encouraging a solution to the Israeli–Palestinian conflict, working for the moderation of Iran, and solidifying gains made in Afghanistan and Central Asia. In an October 2002 speech, Retired Marine Gen. Anthony Zinni, former head of Central Command for U.S. forces in the Middle East and State Department's envoy to the Israeli–Palestinian conflict, called Iraq "maybe six or seven," in terms of U.S. Middle East priorities, adding that "the affordability line may be drawn around five." However, while commander of CENTCOM, Zinni held a very different opinion concerning the threat posed by Iraq. In testimony before the Senate Armed Services Committee in February 2000, Zinni said: "Iraq remains the most significant near-term threat to U.S. interests in the Persian Gulf region. This is primarily due to its large conventional military force, pursuit of WMD, oppressive treatment of Iraqi citizens, refusal to comply with United Nations Security Council Resolutions (UNSCR), persistent threats to enforcement of the No Fly Zones (NFZ), and continued efforts to violate UN Security Council sanctions through oil smuggling." However, it is important to note that Zinni specifically referred to "the Persian Gulf region" in his Senate testimony, which is a significantly smaller region of the world than the "Middle East", which he referred to in 2007.


title: 2003 invasion of Iraq

text: Besides arguing that Iraq was not the top strategic priority in the war on terrorism or in the Middle East, critics of the war also suggested that it could potentially destabilize the surrounding region. Prominent among such critics was Brent Scowcroft, who served as National Security Advisor to George H. W. Bush. In a 15 August 2002 "The Wall Street Journal" editorial entitled "Don't attack Saddam", Scowcroft wrote that, "Possibly the most dire consequences would be the effect in the region ... there would be an explosion of outrage against us ... the results could well destabilize Arab regimes", and, "could even swell the ranks of the terrorists." In an October 2015 CNN interview with Fareed Zakaria, former British Prime Minister Tony Blair apologized for his 'mistakes' over Iraq War and admitted there were 'elements of truth' to the view that the invasion helped promote the rise of ISIS. In the opinion of Hayder al-Khoei, Iraq was already "destined for chaos" before 2003.


title: 2003 invasion of Iraq

text: In a March 2003 Gallup poll, the day after the invasion, 76% of Americans supported the military action against Iraq. In a March 2003 YouGov poll, 54% of Britons had approved of military action against Iraq.


title: 2003 invasion of Iraq

text: A decade later, in 2013, a Gallup poll found that 53% of Americans surveyed believed the Iraq War was a mistake.


title: 2003 invasion of Iraq

text: This campaign featured a variety of new terminology, much of it initially coined by the U.S. government or military. The military official name for the invasion was Operation Iraqi Freedom. Also notable was the usage "death squads" to refer to Fedayeen paramilitary forces. Members of the Saddam Hussein government were called by disparaging nicknames – e.g., "Chemical Ali" (Ali Hassan al-Majid), "Baghdad Bob" or "Comical Ali" (Muhammed Saeed al-Sahaf), and "Mrs. Anthrax" or "Chemical Sally" (Huda Salih Mahdi Ammash).


title: 2003 invasion of Iraq

text: Many slogans and terms coined came to be used by Bush's political opponents, or those opposed to the war. For example, in April 2003 John Kerry, the Democratic candidate in the presidential election, said at a campaign rally: "What we need now is not just a regime change in Saddam Hussein and Iraq, but we need a regime change in the United States."


title: 2003 invasion of Iraq

text: George W. Bush's press secretary Ari Fleischer talked about "Operation Iraqi liberation" in a 2003 press briefing, and "Operation Iraqi Liberation (OIL)" was also used by David Rovics, a popular folk protest singer.


title: Crips

text: The Crips is an alliance of street gangs that is based in the coastal regions of Southern California. Founded in Los Angeles, California, in 1969, mainly by Raymond Washington and Stanley Williams, the Crips were initially a single alliance between two autonomous gangs; it is now a loosely-connected network of individual "sets", often engaged in open warfare with one another. Traditionally, since around 1973, its members have worn blue clothing.


title: Crips

text: The Crips are one of the largest and most violent associations of street gangs in the United States. With an estimated 30,000 to 35,000 members in 2008, the gangs' members have been involved in murders, robberies and drug dealing, among other crimes. They have a long and bitter rivalry with the Bloods.


title: Crips

text: Some sources suggest that the original name for the alliance, "Cribs", was narrowed down from a list of many options and chosen unanimously from three final choices, over the Black Overlords and the Assassins. Cribs was chosen to reflect the young age of the majority of the gang members. The name evolved into "Crips" when gang members began carrying around canes to display their "pimp" status. People in the neighborhood then began calling them cripples, or "Crips" for short. In February 1972 the "Los Angeles Times" used the term. Another source suggests "Crips" may have evolved from "Cripplers", a 1970s street gang in Watts, of which Washington was a member. The name had no political, organizational, cryptic, or acronymic meaning, though some have suggested it stands for "Common Revolution In Progress", a backronym. According to the film "Bastards of the Party", directed by a member of the Bloods, the name represented "Community Revolutionary Interparty Service" or "Community Reform Interparty Service".


title: Crips

text: Gang activity in South Central Los Angeles has its roots in a variety of factors dating to the 1950s, including: post-World War II economic decline leading to joblessness and poverty; racial segregation of young African American men, who were excluded from organizations such as the Boy Scouts, leading to the formation of black "street clubs"; and the waning of black nationalist organizations such as the Black Panther Party and the Black Power Movement.


title: Crips

text: Stanley Tookie Williams met Raymond Lee Washington in 1969, and the two decided to unite their local gang members from the west and east sides of South Central Los Angeles in order to battle neighboring street gangs. Most of the members were 17 years old. Williams however appears to discount the sometimes-cited founding date of 1969 in his memoir, "Blue Rage, Black Redemption".


title: Crips

text: In his memoir, Williams also refuted claims that the group was a spin-off of the Black Panther Party or formed for a community agenda, writing that it "depicted a fighting alliance against street gangs—nothing more, nothing less." Washington, who attended Fremont High School, was the leader of the East Side Crips, and Williams, who attended Washington High School, led the West Side Crips.


title: Crips

text: Williams recalled that a blue bandana was first worn by Crips founding member Curtis "Buddha" Morrow, as a part of his color-coordinated clothing of blue Levis, a blue shirt, and dark blue suspenders. A blue bandana was worn in tribute to Morrow after he was shot and killed on February 23, 1973. The color then became associated with Crips.


title: Crips

text: By 1978, there were 45 Crip gangs, called sets, in Los Angeles. They were heavily involved in the production of PCP, marijuana and amphetamines. On March 11, 1979, Williams, a member of the Westside Crips, was arrested for four murders and on August 9, 1979, Washington was gunned down. Washington had been against Crip infighting and after his death several Crip sets started fighting against each other. The Crips' leadership was dismantled, prompting a deadly gang war between the Rollin' 60 Neighborhood Crips and Eight Tray Gangster Crips that led nearby Crip sets to choose sides and align themselves with either the Neighborhood Crips or the Gangster Crips, waging large-scale war in South Central and other cities. The East Coast Crips (from East Los Angeles) and the Hoover Crips directly severed their alliance after Washington's death. By 1980, the Crips were in turmoil, warring with the Bloods and against each other. The gang's growth and influence increased significantly in the early 1980s when crack cocaine hit the streets and Crip sets began distributing the drug. Large profits induced many Crips to establish new markets in other cities and states. As a result, Crips membership grew steadily and the street gang was one of the nation's largest by the late 1980s. In 1999, there were at least 600 Crip sets with more than 30,000 members transporting drugs in the United States.


title: Crips

text: As of 2015, the Crips gang consists of between approximately 30,000 and 35,000 members and 800 sets, active in 221 cities and 41 U.S. states. The states with the highest estimated number of Crip sets are California, Texas, Oklahoma, and Missouri. Members typically consist of young African American men, but can be white, Hispanic, Asian, and Pacific Islander. The gang also began to establish a presence in Canada in the early 1990s; Crip sets are active in the Canadian cities of Montreal and Toronto.


title: Crips

text: In 1992 the LAPD estimated 15,742 Crips in 108 sets; other source estimates were 30,000 to 35,000 in 600 sets in California.


title: Crips

text: Crips have served in the United States armed forces and on military bases in the United States and abroad.


title: Crips

text: Some practices of Crip gang life include graffiti and substitutions and deletions of particular letters of the alphabet. The letter "b" in the word "blood" is "disrespected" among certain Crip sets and written with a cross inside it because of its association with the enemy. The letters "CK", which are interpreted to stand for "Crip killer", are avoided and replaced by "cc". For example, the words "kick back" are written "kicc bacc", and block is written as "blocc". Many other words and letters are also altered due to symbolic associations. Crips traditionally refer to each other as "Cuz" or "Cuzz", which itself is sometimes used as a moniker for a Crip. "Crab" is the most disrespectful epithet to call a Crip, and can warrant fatal retaliation. Crips in prison modules in the 1970s and 1980s sometimes spoke Swahili to maintain privacy from guards and rival gangs.


title: Crips

text: As with most criminal street gangs, Crips have traditionally benefited monetarily from illicit activities such as illegal gambling, drug-dealing, pimping, larceny, and robbery. Crips also profit from extorting local drug dealers who are not members of the gang. Along with profitable rackets such as these, they have also been known to participate in vandalism and property crime, often for gang-pride reasons or simply enjoyment. This can include public graffiti (tagging) and "joyriding" in stolen vehicles.


title: Crips

text: The gang’s current primary illicit source of income is presumably in street-level drug distribution, however many Crip members may also make notable amounts of illegal funds from the black market sale of illicit firearms. Historically, the gang's size and power was largely augmented by the profits from the street sale of crack cocaine throughout the 1980s showing that PCP, amphetamines and other drugs were not as lucrative for them and thus didn't have as direct of an effect on the group's increase in influence. Therefore, the gang's initial phase of growth and popularity can, in some way, be directly traced back to the explosion crack cocaine in the United States during the 1980s.


title: Crips

text: The Crips became popular throughout southern Los Angeles as more youth gangs joined; at one point they outnumbered non-Crip gangs by 3 to 1, sparking disputes with non-Crip gangs, including the L.A. Brims, Athens Park Boys, the Bishops, The Drill Company, and the Denver Lanes. By 1971 the gang's notoriety had spread across Los Angeles.


title: Crips

text: By 1971, a gang on Piru Street in Compton, California, known as the Piru Street Boys, formed and associated itself with the Crips as a set. After two years of peace, a feud began between the Pirus and the other Crip sets. It later turned violent as gang warfare ensued between former allies. This battle continued and by 1973, the Pirus wanted to end the violence and called a meeting with other gangs targeted by the Crips. After a long discussion, the Pirus broke all connections to the Crips and started an organization that would later be called the Bloods, a street gang infamous for its rivalry with the Crips.


title: Crips

text: Since then, other conflicts and feuds were started between many of the remaining Crip sets. It is a common misconception that Crip sets feud only with Bloods. In reality, they also fight each other—for example, the Rolling 60s Neighborhood Crips and 83 Gangster Crips have been rivals since 1979. In Watts, the Grape Street Crips and the PJ Watts Crips have feuded so much that the PJ Watts Crips even teamed up with a local Blood set, the Bounty Hunter Bloods, to fight the Grape Street Crips. In the mid-1990s, the Hoover Crips rivalries and wars with other Crip sets caused them to become independent and drop the Crip name, calling themselves the Hoover Criminals.


title: Crips

text: The Bloods are the Crips' main stereotypical rival. The Bloods initially formed to provide Piru Street Gang members protection from the Crips. The rivalry started in the 1960s when Washington and other Crip members attacked Sylvester Scott and Benson Owens, two students at Centennial High School. After the incident, Scott formed the Pirus, while Owens established the West Piru gang. In late 1972, several gangs that felt victimized by the Crips due to their escalating attacks joined the Pirus to create a new federation of non-Crip gangs that later became known as Bloods. Between 1972 and 1979, the rivalry between the Crips and Bloods grew, accounting for a majority of the gang-related murders in southern Los Angeles. Members of the Bloods and Crips occasionally fight each other and, as of 2010, are responsible for a significant portion of gang-related murders in Los Angeles. This rivalry is also believed to be behind the 2022 Sacramento shooting, where 6 people were killed.


title: Crips

text: In the late 1980s and early 1990s, as many Crip gang members were being sent to various prisons across the country, an alliance was formed between the Crips and the Folk Nation in Midwest and Southern U.S. prisons. This alliance was established to protect gang members incarcerated in state and federal prison. It is strongest within the prisons, and less effective outside. The alliance between the Crips and Folks is known as "8-ball". A broken 8-ball indicates a disagreement or "beef" between Folks and Crips.


title: Central processing unit

text: A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions in the program. This contrasts with external components such as main memory and I/O circuitry, and specialized processors such as graphics processing units (GPUs).


title: Central processing unit

text: The form, design, and implementation of CPUs have changed over time, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic–logic unit (ALU) that performs arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that orchestrates the fetching (from memory), decoding and execution (of instructions) by directing the coordinated operations of the ALU, registers and other components.


title: Central processing unit

text: Most modern CPUs are implemented on integrated circuit (IC) microprocessors, with one or more CPUs on a single IC chip. Microprocessor chips with multiple CPUs are multi-core processors. The individual physical CPUs, processor cores, can also be multithreaded to create additional virtual or logical CPUs.


title: Central processing unit

text: An IC that contains a CPU may also contain memory, peripheral interfaces, and other components of a computer; such integrated devices are variously called microcontrollers or systems on a chip (SoC).


title: Central processing unit

text: Array processors or vector processors have multiple processors that operate in parallel, with no unit considered central. Virtual CPUs are an abstraction of dynamical aggregated computational resources.


title: Central processing unit

text: Early computers such as the ENIAC had to be physically rewired to perform different tasks, which caused these machines to be called "fixed-program computers". The "central processing unit" term has been in use since as early as 1955. Since the term "CPU" is generally defined as a device for software (computer program) execution, the earliest devices that could rightly be called CPUs came with the advent of the stored-program computer.


title: Central processing unit

text: The idea of a stored-program computer had been already present in the design of J. Presper Eckert and John William Mauchly's ENIAC, but was initially omitted so that it could be finished sooner. On June 30, 1945, before ENIAC was made, mathematician John von Neumann distributed the paper entitled "First Draft of a Report on the EDVAC". It was the outline of a stored-program computer that would eventually be completed in August 1949. EDVAC was designed to perform a certain number of instructions (or operations) of various types. Significantly, the programs written for EDVAC were to be stored in high-speed computer memory rather than specified by the physical wiring of the computer. This overcame a severe limitation of ENIAC, which was the considerable time and effort required to reconfigure the computer to perform a new task. With von Neumann's design, the program that EDVAC ran could be changed simply by changing the contents of the memory. EDVAC, was not the first stored-program computer, the Manchester Baby which was a small-scale experimental stored-program computer, ran its first program on 21 June 1948 and the Manchester Mark 1 ran its first program during the night of 16–17 June 1949.


title: Central processing unit

text: Early CPUs were custom designs used as part of a larger and sometimes distinctive computer. However, this method of designing custom CPUs for a particular application has largely given way to the development of multi-purpose processors produced in large quantities. This standardization began in the era of discrete transistor mainframes and minicomputers and has rapidly accelerated with the popularization of the integrated circuit (IC). The IC has allowed increasingly complex CPUs to be designed and manufactured to tolerances on the order of nanometers. Both the miniaturization and standardization of CPUs have increased the presence of digital devices in modern life far beyond the limited application of dedicated computing machines. Modern microprocessors appear in electronic devices ranging from automobiles to cellphones, and sometimes even in toys.


title: Central processing unit

text: While von Neumann is most often credited with the design of the stored-program computer because of his design of EDVAC, and the design became known as the von Neumann architecture, others before him, such as Konrad Zuse, had suggested and implemented similar ideas. The so-called Harvard architecture of the Harvard Mark I, which was completed before EDVAC, also used a stored-program design using punched paper tape rather than electronic memory. The key difference between the von Neumann and Harvard architectures is that the latter separates the storage and treatment of CPU instructions and data, while the former uses the same memory space for both. Most modern CPUs are primarily von Neumann in design, but CPUs with the Harvard architecture are seen as well, especially in embedded applications; for instance, the Atmel AVR microcontrollers are Harvard architecture processors.


title: Central processing unit

text: Relays and vacuum tubes (thermionic tubes) were commonly used as switching elements; a useful computer requires thousands or tens of thousands of switching devices. The overall speed of a system is dependent on the speed of the switches. Vacuum-tube computers such as EDVAC tended to average eight hours between failures, whereas relay computers like the (slower, but earlier) Harvard Mark I failed very rarely. In the end, tube-based CPUs became dominant because the significant speed advantages afforded generally outweighed the reliability problems. Most of these early synchronous CPUs ran at low clock rates compared to modern microelectronic designs. Clock signal frequencies ranging from 100 kHz to 4 MHz were very common at this time, limited largely by the speed of the switching devices they were built with.


title: Central processing unit

text: The design complexity of CPUs increased as various technologies facilitated building smaller and more reliable electronic devices. The first such improvement came with the advent of the transistor. Transistorized CPUs during the 1950s and 1960s no longer had to be built out of bulky, unreliable and fragile switching elements like vacuum tubes and relays. With this improvement, more complex and reliable CPUs were built onto one or several printed circuit boards containing discrete (individual) components.


title: Central processing unit

text: In 1964, IBM introduced its IBM System/360 computer architecture that was used in a series of computers capable of running the same programs with different speed and performance. This was significant at a time when most electronic computers were incompatible with one another, even those made by the same manufacturer. To facilitate this improvement, IBM used the concept of a microprogram (often called "microcode"), which still sees widespread usage in modern CPUs. The System/360 architecture was so popular that it dominated the mainframe computer market for decades and left a legacy that is still continued by similar modern computers like the IBM zSeries. In 1965, Digital Equipment Corporation (DEC) introduced another influential computer aimed at the scientific and research markets, the PDP-8.


title: Central processing unit

text: Transistor-based computers had several distinct advantages over their predecessors. Aside from facilitating increased reliability and lower power consumption, transistors also allowed CPUs to operate at much higher speeds because of the short switching time of a transistor in comparison to a tube or relay. The increased reliability and dramatically increased speed of the switching elements (which were almost exclusively transistors by this time); CPU clock rates in the tens of megahertz were easily obtained during this period. Additionally, while discrete transistor and IC CPUs were in heavy usage, new high-performance designs like single instruction, multiple data (SIMD) vector processors began to appear. These early experimental designs later gave rise to the era of specialized supercomputers like those made by Cray Inc and Fujitsu Ltd.


title: Central processing unit

text: During this period, a method of manufacturing many interconnected transistors in a compact space was developed. The integrated circuit (IC) allowed a large number of transistors to be manufactured on a single semiconductor-based die, or "chip". At first, only very basic non-specialized digital circuits such as NOR gates were miniaturized into ICs. CPUs based on these "building block" ICs are generally referred to as "small-scale integration" (SSI) devices. SSI ICs, such as the ones used in the Apollo Guidance Computer, usually contained up to a few dozen transistors. To build an entire CPU out of SSI ICs required thousands of individual chips, but still consumed much less space and power than earlier discrete transistor designs.


title: Central processing unit

text: IBM's System/370, follow-on to the System/360, used SSI ICs rather than Solid Logic Technology discrete-transistor modules. DEC's PDP-8/I and KI10 PDP-10 also switched from the individual transistors used by the PDP-8 and PDP-10 to SSI ICs, and their extremely popular PDP-11 line was originally built with SSI ICs but was eventually implemented with LSI components once these became practical.


title: Central processing unit

text: Lee Boysel published influential articles, including a 1967 "manifesto", which described how to build the equivalent of a 32-bit mainframe computer from a relatively small number of large-scale integration circuits (LSI). The only way to build LSI chips, which are chips with a hundred or more gates, was to build them using a metal–oxide–semiconductor (MOS) semiconductor manufacturing process (either PMOS logic, NMOS logic, or CMOS logic). However, some companies continued to build processors out of bipolar transistor–transistor logic (TTL) chips because bipolar junction transistors were faster than MOS chips up until the 1970s (a few companies such as Datapoint continued to build processors out of TTL chips until the early 1980s). In the 1960s, MOS ICs were slower and initially considered useful only in applications that required low power. Following the development of silicon-gate MOS technology by Federico Faggin at Fairchild Semiconductor in 1968, MOS ICs largely replaced bipolar TTL as the standard chip technology in the early 1970s.


title: Central processing unit

text: As the microelectronic technology advanced, an increasing number of transistors were placed on ICs, decreasing the number of individual ICs needed for a complete CPU. MSI and LSI ICs increased transistor counts to hundreds, and then thousands. By 1968, the number of ICs required to build a complete CPU had been reduced to 24 ICs of eight different types, with each IC containing roughly 1000 MOSFETs. In stark contrast with its SSI and MSI predecessors, the first LSI implementation of the PDP-11 contained a CPU composed of only four LSI integrated circuits.


title: Central processing unit

text: Since microprocessors were first introduced they have almost completely overtaken all other central processing unit implementation methods. The first commercially available microprocessor, made in 1971, was the Intel 4004, and the first widely used microprocessor, made in 1974, was the Intel 8080. Mainframe and minicomputer manufacturers of the time launched proprietary IC development programs to upgrade their older computer architectures, and eventually produced instruction set compatible microprocessors that were backward-compatible with their older hardware and software. Combined with the advent and eventual success of the ubiquitous personal computer, the term "CPU" is now applied almost exclusively to microprocessors. Several CPUs (denoted "cores") can be combined in a single processing chip.


title: Central processing unit

text: Previous generations of CPUs were implemented as discrete components and numerous small integrated circuits (ICs) on one or more circuit boards. Microprocessors, on the other hand, are CPUs manufactured on a very small number of ICs; usually just one. The overall smaller CPU size, as a result of being implemented on a single die, means faster switching time because of physical factors like decreased gate parasitic capacitance. This has allowed synchronous microprocessors to have clock rates ranging from tens of megahertz to several gigahertz. Additionally, the ability to construct exceedingly small transistors on an IC has increased the complexity and number of transistors in a single CPU many fold. This widely observed trend is described by Moore's law, which had proven to be a fairly accurate predictor of the growth of CPU (and other IC) complexity until 2016.


title: Central processing unit

text: While the complexity, size, construction and general form of CPUs have changed enormously since 1950, the basic design and function has not changed much at all. Almost all common CPUs today can be very accurately described as von Neumann stored-program machines. As Moore's law no longer holds, concerns have arisen about the limits of integrated circuit transistor technology. Extreme miniaturization of electronic gates is causing the effects of phenomena like electromigration and subthreshold leakage to become much more significant. These newer concerns are among the many factors causing researchers to investigate new methods of computing such as the quantum computer, as well as to expand the usage of parallelism and other methods that extend the usefulness of the classical von Neumann model.


title: Central processing unit

text: The fundamental operation of most CPUs, regardless of the physical form they take, is to execute a sequence of stored instructions that is called a program. The instructions to be executed are kept in some kind of computer memory. Nearly all CPUs follow the fetch, decode and execute steps in their operation, which are collectively known as the instruction cycle.


title: Central processing unit

text: After the execution of an instruction, the entire process repeats, with the next instruction cycle normally fetching the next-in-sequence instruction because of the incremented value in the program counter. If a jump instruction was executed, the program counter will be modified to contain the address of the instruction that was jumped to and program execution continues normally. In more complex CPUs, multiple instructions can be fetched, decoded and executed simultaneously. This section describes what is generally referred to as the "classic RISC pipeline", which is quite common among the simple CPUs used in many electronic devices (often called microcontrollers). It largely ignores the important role of CPU cache, and therefore the access stage of the pipeline.


title: Central processing unit

text: Some instructions manipulate the program counter rather than producing result data directly; such instructions are generally called "jumps" and facilitate program behavior like loops, conditional program execution (through the use of a conditional jump), and existence of functions. In some processors, some other instructions change the state of bits in a "flags" register. These flags can be used to influence how a program behaves, since they often indicate the outcome of various operations. For example, in such processors a "compare" instruction evaluates two values and sets or clears bits in the flags register to indicate which one is greater or whether they are equal; one of these flags could then be used by a later jump instruction to determine program flow.


title: Central processing unit

text: Fetch involves retrieving an instruction (which is represented by a number or sequence of numbers) from program memory. The instruction's location (address) in program memory is determined by the program counter (PC; called the "instruction pointer" in Intel x86 microprocessors), which stores a number that identifies the address of the next instruction to be fetched. After an instruction is fetched, the PC is incremented by the length of the instruction so that it will contain the address of the next instruction in the sequence. Often, the instruction to be fetched must be retrieved from relatively slow memory, causing the CPU to stall while waiting for the instruction to be returned. This issue is largely addressed in modern processors by caches and pipeline architectures (see below).


title: Central processing unit

text: The instruction that the CPU fetches from memory determines what the CPU will do. In the decode step, performed by binary decoder circuitry known as the "instruction decoder", the instruction is converted into signals that control other parts of the CPU.


title: Central processing unit

text: The way in which the instruction is interpreted is defined by the CPU's instruction set architecture (ISA). Often, one group of bits (that is, a "field") within the instruction, called the opcode, indicates which operation is to be performed, while the remaining fields usually provide supplemental information required for the operation, such as the operands. Those operands may be specified as a constant value (called an immediate value), or as the location of a value that may be a processor register or a memory address, as determined by some addressing mode.


title: Central processing unit

text: In some CPU designs the instruction decoder is implemented as a hardwired, unchangeable binary decoder circuit. In others, a microprogram is used to translate instructions into sets of CPU configuration signals that are applied sequentially over multiple clock pulses. In some cases the memory that stores the microprogram is rewritable, making it possible to change the way in which the CPU decodes instructions.


title: Central processing unit

text: After the fetch and decode steps, the execute step is performed. Depending on the CPU architecture, this may consist of a single action or a sequence of actions. During each action, control signals electrically enable or disable various parts of the CPU so they can perform all or part of the desired operation. The action is then completed, typically in response to a clock pulse. Very often the results are written to an internal CPU register for quick access by subsequent instructions. In other cases results may be written to slower, but less expensive and higher capacity main memory.


title: Central processing unit

text: For example, if an addition instruction is to be executed, registers containing operands (numbers to be summed) are activated, as are the parts of the arithmetic logic unit (ALU) that perform addition. When the clock pulse occurs, the operands flow from the source registers into the ALU, and the sum appears at its output. On subsequent clock pulses, other components are enabled (and disabled) to move the output (the sum of the operation) to storage (e.g., a register or memory). If the resulting sum is too large (i.e., it is larger than the ALU's output word size), an arithmetic overflow flag will be set, influencing the next operation.


title: Central processing unit

text: Hardwired into a CPU's circuitry is a set of basic operations it can perform, called an instruction set. Such operations may involve, for example, adding or subtracting two numbers, comparing two numbers, or jumping to a different part of a program. Each instruction is represented by a unique combination of bits, known as the machine language opcode. While processing an instruction, the CPU decodes the opcode (via a binary decoder) into control signals, which orchestrate the behavior of the CPU. A complete machine language instruction consists of an opcode and, in many cases, additional bits that specify arguments for the operation (for example, the numbers to be summed in the case of an addition operation). Going up the complexity scale, a machine language program is a collection of machine language instructions that the CPU executes.


title: Central processing unit

text: The actual mathematical operation for each instruction is performed by a combinational logic circuit within the CPU's processor known as the arithmetic–logic unit or ALU. In general, a CPU executes an instruction by fetching it from memory, using its ALU to perform an operation, and then storing the result to memory. Beside the instructions for integer mathematics and logic operations, various other machine instructions exist, such as those for loading data from memory and storing it back, branching operations, and mathematical operations on floating-point numbers performed by the CPU's floating-point unit (FPU).


title: Central processing unit

text: The control unit (CU) is a component of the CPU that directs the operation of the processor. It tells the computer's memory, arithmetic and logic unit and input and output devices how to respond to the instructions that have been sent to the processor.


title: Central processing unit

text: It directs the operation of the other units by providing timing and control signals. Most computer resources are managed by the CU. It directs the flow of data between the CPU and the other devices. John von Neumann included the control unit as part of the von Neumann architecture. In modern computer designs, the control unit is typically an internal part of the CPU with its overall role and operation unchanged since its introduction.


title: Central processing unit

text: The arithmetic logic unit (ALU) is a digital circuit within the processor that performs integer arithmetic and bitwise logic operations. The inputs to the ALU are the data words to be operated on (called operands), status information from previous operations, and a code from the control unit indicating which operation to perform. Depending on the instruction being executed, the operands may come from internal CPU registers, external memory, or constants generated by the ALU itself.


title: Central processing unit

text: When all input signals have settled and propagated through the ALU circuitry, the result of the performed operation appears at the ALU's outputs. The result consists of both a data word, which may be stored in a register or memory, and status information that is typically stored in a special, internal CPU register reserved for this purpose.


title: Central processing unit

text: Address generation unit (AGU), sometimes also called address computation unit (ACU), is an execution unit inside the CPU that calculates addresses used by the CPU to access main memory. By having address calculations handled by separate circuitry that operates in parallel with the rest of the CPU, the number of CPU cycles required for executing various machine instructions can be reduced, bringing performance improvements.


title: Central processing unit

text: While performing various operations, CPUs need to calculate memory addresses required for fetching data from the memory; for example, in-memory positions of array elements must be calculated before the CPU can fetch the data from actual memory locations. Those address-generation calculations involve different integer arithmetic operations, such as addition, subtraction, modulo operations, or bit shifts. Often, calculating a memory address involves more than one general-purpose machine instruction, which do not necessarily decode and execute quickly. By incorporating an AGU into a CPU design, together with introducing specialized instructions that use the AGU, various address-generation calculations can be offloaded from the rest of the CPU, and can often be executed quickly in a single CPU cycle.


title: Central processing unit

text: Capabilities of an AGU depend on a particular CPU and its architecture. Thus, some AGUs implement and expose more address-calculation operations, while some also include more advanced specialized instructions that can operate on multiple operands at a time. Some CPU architectures include multiple AGUs so more than one address-calculation operation can be executed simultaneously, which brings further performance improvements due to the superscalar nature of advanced CPU designs. For example, Intel incorporates multiple AGUs into its Sandy Bridge and Haswell microarchitectures, which increase bandwidth of the CPU memory subsystem by allowing multiple memory-access instructions to be executed in parallel.


title: Central processing unit

text: Many microprocessors (in smartphones and desktop, laptop, server computers) have a memory management unit, translating logical addresses into physical RAM addresses, providing memory protection and paging abilities, useful for virtual memory. Simpler processors, especially microcontrollers, usually don't include an MMU.


title: Central processing unit

text: A CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory. A cache is a smaller, faster memory, closer to a processor core, which stores copies of the data from frequently used main memory locations. Most CPUs have different independent caches, including instruction and data caches, where the data cache is usually organized as a hierarchy of more cache levels (L1, L2, L3, L4, etc.).


title: Central processing unit

text: All modern (fast) CPUs (with few specialized exceptions) have multiple levels of CPU caches. The first CPUs that used a cache had only one level of cache; unlike later level 1 caches, it was not split into L1d (for data) and L1i (for instructions). Almost all current CPUs with caches have a split L1 cache. They also have L2 caches and, for larger processors, L3 caches as well. The L2 cache is usually not split and acts as a common repository for the already split L1 cache. Every core of a multi-core processor has a dedicated L2 cache and is usually not shared between the cores. The L3 cache, and higher-level caches, are shared between the cores and are not split. An L4 cache is currently uncommon, and is generally on dynamic random-access memory (DRAM), rather than on static random-access memory (SRAM), on a separate die or chip. That was also the case historically with L1, while bigger chips have allowed integration of it and generally all cache levels, with the possible exception of the last level. Each extra level of cache tends to be bigger and be optimized differently.


title: Central processing unit

text: Other types of caches exist (that are not counted towards the "cache size" of the most important caches mentioned above), such as the translation lookaside buffer (TLB) that is part of the memory management unit (MMU) that most CPUs have.


title: Central processing unit

text: Caches are generally sized in powers of two: 2, 8, 16 etc. KiB or MiB (for larger non-L1) sizes, although the IBM z13 has a 96 KiB L1 instruction cache.


title: Central processing unit

text: Most CPUs are synchronous circuits, which means they employ a clock signal to pace their sequential operations. The clock signal is produced by an external oscillator circuit that generates a consistent number of pulses each second in the form of a periodic square wave. The frequency of the clock pulses determines the rate at which a CPU executes instructions and, consequently, the faster the clock, the more instructions the CPU will execute each second.


title: Central processing unit

text: To ensure proper operation of the CPU, the clock period is longer than the maximum time needed for all signals to propagate (move) through the CPU. In setting the clock period to a value well above the worst-case propagation delay, it is possible to design the entire CPU and the way it moves data around the "edges" of the rising and falling clock signal. This has the advantage of simplifying the CPU significantly, both from a design perspective and a component-count perspective. However, it also carries the disadvantage that the entire CPU must wait on its slowest elements, even though some portions of it are much faster. This limitation has largely been compensated for by various methods of increasing CPU parallelism (see below).


title: Central processing unit

text: However, architectural improvements alone do not solve all of the drawbacks of globally synchronous CPUs. For example, a clock signal is subject to the delays of any other electrical signal. Higher clock rates in increasingly complex CPUs make it more difficult to keep the clock signal in phase (synchronized) throughout the entire unit. This has led many modern CPUs to require multiple identical clock signals to be provided to avoid delaying a single signal significantly enough to cause the CPU to malfunction. Another major issue, as clock rates increase dramatically, is the amount of heat that is dissipated by the CPU. The constantly changing clock causes many components to switch regardless of whether they are being used at that time. In general, a component that is switching uses more energy than an element in a static state. Therefore, as clock rate increases, so does energy consumption, causing the CPU to require more heat dissipation in the form of CPU cooling solutions.


title: Central processing unit

text: One method of dealing with the switching of unneeded components is called clock gating, which involves turning off the clock signal to unneeded components (effectively disabling them). However, this is often regarded as difficult to implement and therefore does not see common usage outside of very low-power designs. One notable recent CPU design that uses extensive clock gating is the IBM PowerPC-based Xenon used in the Xbox 360; that way, power requirements of the Xbox 360 are greatly reduced.


title: Central processing unit

text: Another method of addressing some of the problems with a global clock signal is the removal of the clock signal altogether. While removing the global clock signal makes the design process considerably more complex in many ways, asynchronous (or clockless) designs carry marked advantages in power consumption and heat dissipation in comparison with similar synchronous designs. While somewhat uncommon, entire asynchronous CPUs have been built without using a global clock signal. Two notable examples of this are the ARM compliant AMULET and the MIPS R3000 compatible MiniMIPS.


title: Central processing unit

text: Rather than totally removing the clock signal, some CPU designs allow certain portions of the device to be asynchronous, such as using asynchronous ALUs in conjunction with superscalar pipelining to achieve some arithmetic performance gains. While it is not altogether clear whether totally asynchronous designs can perform at a comparable or better level than their synchronous counterparts, it is evident that they do at least excel in simpler math operations. This, combined with their excellent power consumption and heat dissipation properties, makes them very suitable for embedded computers.


title: Central processing unit

text: Many modern CPUs have a die-integrated power managing module which regulates on-demand voltage supply to the CPU circuitry allowing it to keep balance between performance and power consumption.


title: Central processing unit

text: Every CPU represents numerical values in a specific way. For example, some early digital computers represented numbers as familiar decimal (base 10) numeral system values, and others have employed more unusual representations such as ternary (base three). Nearly all modern CPUs represent numbers in binary form, with each digit being represented by some two-valued physical quantity such as a "high" or "low" voltage.


title: Central processing unit

text: Related to numeric representation is the size and precision of integer numbers that a CPU can represent. In the case of a binary CPU, this is measured by the number of bits (significant digits of a binary encoded integer) that the CPU can process in one operation, which is commonly called "word size", "bit width", "data path width", "integer precision", or "integer size". A CPU's integer size determines the range of integer values it can directly operate on. For example, an 8-bit CPU can directly manipulate integers represented by eight bits, which have a range of 256 (2) discrete integer values.


title: Central processing unit

text: Integer range can also affect the number of memory locations the CPU can directly address (an address is an integer value representing a specific memory location). For example, if a binary CPU uses 32 bits to represent a memory address then it can directly address 2 memory locations. To circumvent this limitation and for various other reasons, some CPUs use mechanisms (such as bank switching) that allow additional memory to be addressed.


title: Central processing unit

text: CPUs with larger word sizes require more circuitry and consequently are physically larger, cost more and consume more power (and therefore generate more heat). As a result, smaller 4- or 8-bit microcontrollers are commonly used in modern applications even though CPUs with much larger word sizes (such as 16, 32, 64, even 128-bit) are available. When higher performance is required, however, the benefits of a larger word size (larger data ranges and address spaces) may outweigh the disadvantages. A CPU can have internal data paths shorter than the word size to reduce size and cost. For example, even though the IBM System/360 instruction set was a 32-bit instruction set, the System/360 Model 30 and Model 40 had 8-bit data paths in the arithmetic logical unit, so that a 32-bit add required four cycles, one for each 8 bits of the operands, and, even though the Motorola 68000 series instruction set was a 32-bit instruction set, the Motorola 68000 and Motorola 68010 had 16-bit data paths in the arithmetic logical unit, so that a 32-bit add required two cycles.


title: Central processing unit

text: To gain some of the advantages afforded by both lower and higher bit lengths, many instruction sets have different bit widths for integer and floating-point data, allowing CPUs implementing that instruction set to have different bit widths for different portions of the device. For example, the IBM System/360 instruction set was primarily 32 bit, but supported 64-bit floating-point values to facilitate greater accuracy and range in floating-point numbers. The System/360 Model 65 had an 8-bit adder for decimal and fixed-point binary arithmetic and a 60-bit adder for floating-point arithmetic. Many later CPU designs use similar mixed bit width, especially when the processor is meant for general-purpose usage where a reasonable balance of integer and floating-point capability is required.


title: Central processing unit

text: The description of the basic operation of a CPU offered in the previous section describes the simplest form that a CPU can take. This type of CPU, usually referred to as "subscalar", operates on and executes one instruction on one or two pieces of data at a time, that is less than one instruction per clock cycle ().


title: Central processing unit

text: This process gives rise to an inherent inefficiency in subscalar CPUs. Since only one instruction is executed at a time, the entire CPU must wait for that instruction to complete before proceeding to the next instruction. As a result, the subscalar CPU gets "hung up" on instructions which take more than one clock cycle to complete execution. Even adding a second execution unit (see below) does not improve performance much; rather than one pathway being hung up, now two pathways are hung up and the number of unused transistors is increased. This design, wherein the CPU's execution resources can operate on only one instruction at a time, can only possibly reach "scalar" performance (one instruction per clock cycle, ). However, the performance is nearly always subscalar (less than one instruction per clock cycle, ).


title: Central processing unit

text: Attempts to achieve scalar and better performance have resulted in a variety of design methodologies that cause the CPU to behave less linearly and more in parallel. When referring to parallelism in CPUs, two terms are generally used to classify these design techniques:


title: Central processing unit

text: Each methodology differs both in the ways in which they are implemented, as well as the relative effectiveness they afford in increasing the CPU's performance for an application.


title: Central processing unit

text: One of the simplest methods for increased parallelism is to begin the first steps of instruction fetching and decoding before the prior instruction finishes executing. This is a technique known as instruction pipelining, and is used in almost all modern general-purpose CPUs. Pipelining allows multiple instruction to be executed at a time by breaking the execution pathway into discrete stages. This separation can be compared to an assembly line, in which an instruction is made more complete at each stage until it exits the execution pipeline and is retired.


title: Central processing unit

text: Pipelining does, however, introduce the possibility for a situation where the result of the previous operation is needed to complete the next operation; a condition often termed data dependency conflict. Therefore pipelined processors must check for these sorts of conditions and delay a portion of the pipeline if necessary. A pipelined processor can become very nearly scalar, inhibited only by pipeline stalls (an instruction spending more than one clock cycle in a stage).


title: Central processing unit

text: Improvements in instruction pipelining led to further decreases in the idle time of CPU components. Designs that are said to be superscalar include a long instruction pipeline and multiple identical execution units, such as load–store units, arithmetic–logic units, floating-point units and address generation units. In a superscalar pipeline, instructions are read and passed to a dispatcher, which decides whether or not the instructions can be executed in parallel (simultaneously). If so, they are dispatched to execution units, resulting in their simultaneous execution. In general, the number of instructions that a superscalar CPU will complete in a cycle is dependent on the number of instructions it is able to dispatch simultaneously to execution units.


title: Central processing unit

text: Most of the difficulty in the design of a superscalar CPU architecture lies in creating an effective dispatcher. The dispatcher needs to be able to quickly determine whether instructions can be executed in parallel, as well as dispatch them in such a way as to keep as many execution units busy as possible. This requires that the instruction pipeline is filled as often as possible and requires significant amounts of CPU cache. It also makes hazard-avoiding techniques like branch prediction, speculative execution, register renaming, out-of-order execution and transactional memory crucial to maintaining high levels of performance. By attempting to predict which branch (or path) a conditional instruction will take, the CPU can minimize the number of times that the entire pipeline must wait until a conditional instruction is completed. Speculative execution often provides modest performance increases by executing portions of code that may not be needed after a conditional operation completes. Out-of-order execution somewhat rearranges the order in which instructions are executed to reduce delays due to data dependencies. Also in case of single instruction stream, multiple data stream—a case when a lot of data from the same type has to be processed—, modern processors can disable parts of the pipeline so that when a single instruction is executed many times, the CPU skips the fetch and decode phases and thus greatly increases performance on certain occasions, especially in highly monotonous program engines such as video creation software and photo processing.


title: Central processing unit

text: When just a fraction of the CPU is superscalar, the part that is not suffers a performance penalty due to scheduling stalls. The Intel P5 Pentium had two superscalar ALUs which could accept one instruction per clock cycle each, but its FPU could not. Thus the P5 was integer superscalar but not floating point superscalar. Intel's successor to the P5 architecture, P6, added superscalar abilities to its floating-point features.


title: Central processing unit

text: Simple pipelining and superscalar design increase a CPU's ILP by allowing it to execute instructions at rates surpassing one instruction per clock cycle. Most modern CPU designs are at least somewhat superscalar, and nearly all general purpose CPUs designed in the last decade are superscalar. In later years some of the emphasis in designing high-ILP computers has been moved out of the CPU's hardware and into its software interface, or instruction set architecture (ISA). The strategy of the very long instruction word (VLIW) causes some ILP to become implied directly by the software, reducing the CPU’s work in boosting ILP and thereby reducing design complexity.


title: Central processing unit

text: Another strategy of achieving performance is to execute multiple threads or processes in parallel. This area of research is known as parallel computing. In Flynn's taxonomy, this strategy is known as multiple instruction stream, multiple data stream (MIMD).


title: Central processing unit

text: One technology used for this purpose was multiprocessing (MP). The initial flavor of this technology is known as symmetric multiprocessing (SMP), where a small number of CPUs share a coherent view of their memory system. In this scheme, each CPU has additional hardware to maintain a constantly up-to-date view of memory. By avoiding stale views of memory, the CPUs can cooperate on the same program and programs can migrate from one CPU to another. To increase the number of cooperating CPUs beyond a handful, schemes such as non-uniform memory access (NUMA) and directory-based coherence protocols were introduced in the 1990s. SMP systems are limited to a small number of CPUs while NUMA systems have been built with thousands of processors. Initially, multiprocessing was built using multiple discrete CPUs and boards to implement the interconnect between the processors. When the processors and their interconnect are all implemented on a single chip, the technology is known as chip-level multiprocessing (CMP) and the single chip as a multi-core processor.


title: Central processing unit

text: It was later recognized that finer-grain parallelism existed with a single program. A single program might have several threads (or functions) that could be executed separately or in parallel. Some of the earliest examples of this technology implemented input/output processing such as direct memory access as a separate thread from the computation thread. A more general approach to this technology was introduced in the 1970s when systems were designed to run multiple computation threads in parallel. This technology is known as multi-threading (MT). This approach is considered more cost-effective than multiprocessing, as only a small number of components within a CPU is replicated to support MT as opposed to the entire CPU in the case of MP. In MT, the execution units and the memory system including the caches are shared among multiple threads. The downside of MT is that the hardware support for multithreading is more visible to software than that of MP and thus supervisor software like operating systems have to undergo larger changes to support MT. One type of MT that was implemented is known as temporal multithreading, where one thread is executed until it is stalled waiting for data to return from external memory. In this scheme, the CPU would then quickly context switch to another thread which is ready to run, the switch often done in one CPU clock cycle, such as the UltraSPARC T1. Another type of MT is simultaneous multithreading, where instructions from multiple threads are executed in parallel within one CPU clock cycle.


title: Central processing unit

text: For several decades from the 1970s to early 2000s, the focus in designing high performance general purpose CPUs was largely on achieving high ILP through technologies such as pipelining, caches, superscalar execution, out-of-order execution, etc. This trend culminated in large, power-hungry CPUs such as the Intel Pentium 4. By the early 2000s, CPU designers were thwarted from achieving higher performance from ILP techniques due to the growing disparity between CPU operating frequencies and main memory operating frequencies as well as escalating CPU power dissipation owing to more esoteric ILP techniques.


title: Central processing unit

text: CPU designers then borrowed ideas from commercial computing markets such as transaction processing, where the aggregate performance of multiple programs, also known as throughput computing, was more important than the performance of a single thread or process.


title: Central processing unit

text: This reversal of emphasis is evidenced by the proliferation of dual and more core processor designs and notably, Intel's newer designs resembling its less superscalar P6 architecture. Late designs in several processor families exhibit CMP, including the x86-64 Opteron and Athlon 64 X2, the SPARC UltraSPARC T1, IBM POWER4 and POWER5, as well as several video game console CPUs like the Xbox 360's triple-core PowerPC design, and the PlayStation 3's 7-core Cell microprocessor.


title: Central processing unit

text: A less common but increasingly important paradigm of processors (and indeed, computing in general) deals with data parallelism. The processors discussed earlier are all referred to as some type of scalar device. As the name implies, vector processors deal with multiple pieces of data in the context of one instruction. This contrasts with scalar processors, which deal with one piece of data for every instruction. Using Flynn's taxonomy, these two schemes of dealing with data are generally referred to as "single instruction" stream, "multiple data" stream (SIMD) and "single instruction" stream, "single data" stream (SISD), respectively. The great utility in creating processors that deal with vectors of data lies in optimizing tasks that tend to require the same operation (for example, a sum or a dot product) to be performed on a large set of data. Some classic examples of these types of tasks include multimedia applications (images, video and sound), as well as many types of scientific and engineering tasks. Whereas a scalar processor must complete the entire process of fetching, decoding and executing each instruction and value in a set of data, a vector processor can perform a single operation on a comparatively large set of data with one instruction. This is only possible when the application tends to require many steps which apply one operation to a large set of data.


title: Central processing unit

text: Most early vector processors, such as the Cray-1, were associated almost exclusively with scientific research and cryptography applications. However, as multimedia has largely shifted to digital media, the need for some form of SIMD in general-purpose processors has become significant. Shortly after inclusion of floating-point units started to become commonplace in general-purpose processors, specifications for and implementations of SIMD execution units also began to appear for general-purpose processors. Some of these early SIMD specifications – like HP's Multimedia Acceleration eXtensions (MAX) and Intel's MMX – were integer-only. This proved to be a significant impediment for some software developers, since many of the applications that benefit from SIMD primarily deal with floating-point numbers. Progressively, developers refined and remade these early designs into some of the common modern SIMD specifications, which are usually associated with one instruction set architecture (ISA). Some notable modern examples include Intel's Streaming SIMD Extensions (SSE) and the PowerPC-related AltiVec (also known as VMX).


title: Central processing unit

text: Many modern architectures (including embedded ones) often include hardware performance counters (HPC), which enables low-level (instruction-level) collection, benchmarking, debugging or analysis of running software metrics. HPC may also be used to discover and analyze unusual or suspicious activity of the software, such as return-oriented programming (ROP) or sigreturn-oriented programming (SROP) exploits etc. This is usually done by software-security teams to assess and find malicious binary programs.


title: Central processing unit

text: Many major vendors (such as IBM, Intel, AMD, and Arm etc.) provide software interfaces (usually written in C/C++) that can be used to collected data from CPUs registers in order to get metrics. Operating system vendors also provide software like codice_1 (Linux) to record, benchmark, or trace CPU events running kernels and applications.


title: Central processing unit

text: A host is the virtual equivalent of a physical machine, on which a virtual system is operating. When there are several physical machines operating in tandem and managed as a whole, the grouped computing and memory resources form a cluster. In some systems, it is possible to dynamically add and remove from a cluster. Resources available at a host and cluster level can be partitioned out into resources pools with fine granularity.


title: Central processing unit

text: The "performance" or "speed" of a processor depends on, among many other factors, the clock rate (generally given in multiples of hertz) and the instructions per clock (IPC), which together are the factors for the instructions per second (IPS) that the CPU can perform.


title: Central processing unit

text: Many reported IPS values have represented "peak" execution rates on artificial instruction sequences with few branches, whereas realistic workloads consist of a mix of instructions and applications, some of which take longer to execute than others. The performance of the memory hierarchy also greatly affects processor performance, an issue barely considered in MIPS calculations. Because of these problems, various standardized tests, often called "benchmarks" for this purposesuch as SPECinthave been developed to attempt to measure the real effective performance in commonly used applications.


title: Central processing unit

text: Processing performance of computers is increased by using multi-core processors, which essentially is plugging two or more individual processors (called "cores" in this sense) into one integrated circuit. Ideally, a dual core processor would be nearly twice as powerful as a single core processor. In practice, the performance gain is far smaller, only about 50%, due to imperfect software algorithms and implementation. Increasing the number of cores in a processor (i.e. dual-core, quad-core, etc.) increases the workload that can be handled. This means that the processor can now handle numerous asynchronous events, interrupts, etc. which can take a toll on the CPU when overwhelmed. These cores can be thought of as different floors in a processing plant, with each floor handling a different task. Sometimes, these cores will handle the same tasks as cores adjacent to them if a single core is not enough to handle the information.


title: Central processing unit

text: Due to specific capabilities of modern CPUs, such as simultaneous multithreading and uncore, which involve sharing of actual CPU resources while aiming at increased utilization, monitoring performance levels and hardware use gradually became a more complex task. As a response, some CPUs implement additional hardware logic that monitors actual use of various parts of a CPU and provides various counters accessible to software; an example is Intel's "Performance Counter Monitor" technology.


title: Oxycodone

text: Oxycodone, sold under various brand names such as Roxicodone and OxyContin (which is the extended release form), is a strong, semi-synthetic opioid used medically for treatment of moderate to severe pain. It is highly addictive and a commonly abused drug. It is usually taken by mouth, and is available in immediate-release and controlled-release formulations. Onset of pain relief typically begins within fifteen minutes and lasts for up to six hours with the immediate-release formulation. In the United Kingdom, it is available by injection. Combination products are also available with paracetamol (acetaminophen), ibuprofen, naloxone, naltrexone, and aspirin.


title: Oxycodone

text: Common side effects include euphoria, constipation, nausea, vomiting, loss of appetite, drowsiness, dizziness, itching, dry mouth, and sweating. Severe side effects may include addiction and dependence, substance abuse, irritability, depression or mania, delirium, hallucinations, hypoventilation, gastroparesis, bradycardia, and hypotension. Those allergic to codeine may also be allergic to oxycodone. Use of oxycodone in early pregnancy appears relatively safe. Opioid withdrawal may occur if rapidly stopped. Oxycodone acts by activating the μ-opioid receptor. When taken by mouth, it has roughly 1.5 times the effect of the equivalent amount of morphine.


title: Oxycodone

text: Oxycodone was first made in Germany in 1916 from thebaine. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication. In 2020, it was the 54th most commonly prescribed medication in the United States, with more than 12million prescriptions. A number of abuse-deterrent formulations are available, such as in combination with naloxone or naltrexone.


title: Oxycodone

text: Oxycodone is used for managing moderate to severe acute or chronic pain when other treatments are not sufficient. It may improve quality of life in certain types of pain. It is unclear if use in chronic pain results in improved quality of life or ongoing pain relief.


title: Oxycodone

text: Oxycodone is available as a controlled-release tablet, intended to be taken every 12 hours. A July 1996 study independent of Purdue Pharma, the drug's originator, found the controlled-release formulation had a variable duration of action ranging from 10 to 12 hours. A 2006 review found that controlled-release oxycodone is comparable to immediate-release oxycodone, morphine, and hydromorphone in management of moderate to severe cancer pain, with fewer side effects than morphine. The author concluded that the controlled-release form is a valid alternative to morphine and a first-line treatment for cancer pain. In 2014, the European Association for Palliative Care recommended oxycodone by mouth as a second-line alternative to morphine by mouth for cancer pain.


title: Oxycodone

text: In the U.S., extended-release oxycodone is approved for use in children as young as eleven years old. The approved uses are for the relief of cancer pain, trauma pain, or pain due to major surgery, in children already treated with opioids, who can tolerate at least 20 mg per day of oxycodone; this provides an alternative to Duragesic (fentanyl), the only other extended-release opioid analgesic approved for children.


title: Oxycodone

text: In the US, oxycodone is only approved for use by mouth, available as tablets and oral solutions. Parenteral formulations of oxycodone (brand name OxyNorm) are also available in other parts of the world, however, and are widely used in the European Union. In Spain, the Netherlands and the United Kingdom, oxycodone is approved for intravenous (IV) and intramuscular (IM) use. When first introduced in Germany during World War I, both IV and IM administrations of oxycodone were commonly used for postoperative pain management of Central Powers soldiers.


title: Oxycodone

text: Most common side effects of oxycodone include reduced sensitivity to pain, delayed gastric emptying, euphoria, anxiolysis, feelings of relaxation, and respiratory depression. Common side effects of oxycodone include constipation (23%), nausea (23%), vomiting (12%), somnolence (23%), dizziness (13%), itching (13%), dry mouth (6%), and sweating (5%). Less common side effects (experienced by less than 5% of patients) include loss of appetite, nervousness, abdominal pain, diarrhea, urinary retention, dyspnea, and hiccups. Most side effects generally become less intense over time, although issues related to constipation are likely to continue for the duration of use. Oxycodone in combination with naloxone in managed-release tablets, has been formulated to both deter abuse and reduce "opioid-induced constipation".


title: Oxycodone

text: The risk of experiencing severe withdrawal symptoms is high if a patient has become physically dependent and discontinues oxycodone abruptly. Medically, when the drug has been taken regularly over an extended period, it is withdrawn gradually rather than abruptly. People who regularly use oxycodone recreationally or at higher than prescribed doses are at even higher risk of severe withdrawal symptoms. The symptoms of oxycodone withdrawal, as with other opioids, may include "anxiety, panic attack, nausea, insomnia, muscle pain, muscle weakness, fevers, and other flu-like symptoms".


title: Oxycodone

text: Withdrawal symptoms have also been reported in newborns whose mothers had been either injecting or orally taking oxycodone during pregnancy.


title: Oxycodone

text: As with other opioids, chronic use of oxycodone (particularly with higher doses) often causes concurrent hypogonadism (low sex hormone levels).


title: Oxycodone

text: In high doses, overdoses, or in some persons not tolerant to opioids, oxycodone can cause shallow breathing, slowed heart rate, cold/clammy skin, pauses in breathing, low blood pressure, constricted pupils, circulatory collapse, respiratory arrest, and death.


title: Oxycodone

text: In 2011, it was the leading cause of drug-related deaths in the U.S. However, from 2012 onwards, heroin and fentanyl have become more common causes of drug-related deaths.


title: Oxycodone

text: Oxycodone overdose has also been described to cause spinal cord infarction in high doses and ischemic damage to the brain, due to prolonged hypoxia from suppressed breathing.


title: Oxycodone

text: Oxycodone is metabolized by the enzymes CYP3A4 and CYP2D6. Therefore, its clearance can be altered by inhibitors and inducers of these enzymes, increasing and decreasing half-life, respectively. (For lists of CYP3A4 and CYP2D6 inhibitors and inducers, see here and here, respectively.) Natural genetic variation in these enzymes can also influence the clearance of oxycodone, which may be related to the wide inter-individual variability in its half-life and potency.


title: Oxycodone

text: Ritonavir or lopinavir/ritonavir greatly increase plasma concentrations of oxycodone in healthy human volunteers due to inhibition of CYP3A4 and CYP2D6. Rifampicin greatly reduces plasma concentrations of oxycodone due to strong induction of CYP3A4. There is also a case report of fosphenytoin, a CYP3A4 inducer, dramatically reducing the analgesic effects of oxycodone in a chronic pain patient. Dosage or medication adjustments may be necessary in each case.


title: Oxycodone

text: Oxycodone, a semi-synthetic opioid, is a highly selective full agonist of the μ-opioid receptor (MOR). This is the main biological target of the endogenous opioid neuropeptide β-endorphin. Oxycodone has low affinity for the δ-opioid receptor (DOR) and the κ-opioid receptor (KOR), where it is an agonist similarly. After oxycodone binds to the MOR, a G protein-complex is released, which inhibits the release of neurotransmitters by the cell by decreasing the amount of cAMP produced, closing calcium channels, and opening potassium channels. Opioids like oxycodone are thought to produce their analgesic effects via activation of the MOR in the midbrain periaqueductal gray (PAG) and rostral ventromedial medulla (RVM). Conversely, they are thought to produce reward and addiction via activation of the MOR in the mesolimbic reward pathway, including in the ventral tegmental area, nucleus accumbens, and ventral pallidum. Tolerance to the analgesic and rewarding effects of opioids is complex and occurs due to receptor-level tolerance (e.g., MOR downregulation), cellular-level tolerance (e.g., cAMP upregulation), and system-level tolerance (e.g., neural adaptation due to induction of ΔFosB expression).


title: Oxycodone

text: Taken orally, 20 mg of immediate-release oxycodone is considered to be equivalent in analgesic effect to 30 mg of morphine, while extended release oxycodone is considered to be twice as potent as oral morphine.


title: Oxycodone

text: Similarly to most other opioids, oxycodone increases prolactin secretion, but its influence on testosterone levels is unknown. Unlike morphine, oxycodone lacks immunosuppressive activity (measured by natural killer cell activity and interleukin 2 production "in vitro"); the clinical relevance of this has not been clarified.


title: Oxycodone

text: A few of the metabolites of oxycodone have also been found to be active as MOR agonists, some of which notably have much higher affinity for (as well as higher efficacy at) the MOR in comparison. Oxymorphone possesses 3- to 5-fold higher affinity for the MOR than does oxycodone, while noroxycodone and noroxymorphone possess one-third of and 3-fold higher affinity for the MOR, respectively, and MOR activation is 5- to 10-fold less with noroxycodone but 2-fold higher with noroxymorphone relative to oxycodone. Noroxycodone, noroxymorphone, and oxymorphone also have longer biological half-lives than oxycodone.


title: Oxycodone

text: However, despite the greater "in vitro" activity of some of its metabolites, it has been determined that oxycodone itself is responsible for 83.0% and 94.8% of its analgesic effect following oral and intravenous administration, respectively. Oxymorphone plays only a minor role, being responsible for 15.8% and 4.5% of the analgesic effect of oxycodone after oral and intravenous administration, respectively. Although the CYP2D6 genotype and the route of administration result in differential rates of oxymorphone formation, the unchanged parent compound remains the major contributor to the overall analgesic effect of oxycodone. In contrast to oxycodone and oxymorphone, noroxycodone and noroxymorphone, while also potent MOR agonists, poorly cross the blood–brain barrier into the central nervous system, and for this reason are only minimally analgesic in comparison.


title: Oxycodone

text: In 1997, a group of Australian researchers proposed (based on a study in rats) that oxycodone acts on KORs, unlike morphine, which acts upon MORs. Further research by this group indicated the drug appears to be a high-affinity κ-opioid receptor agonist. However, this conclusion has been disputed, primarily on the basis that oxycodone produces effects that are typical of MOR agonists. In 2006, research by a Japanese group suggested the effect of oxycodone is mediated by different receptors in different situations. Specifically in diabetic mice, the KOR appears to be involved in the antinociceptive effects of oxycodone, while in nondiabetic mice, the μ-opioid receptor seems to be primarily responsible for these effects.


title: Oxycodone

text: Oxycodone can be administered orally, intranasally, via intravenous, intramuscular, or subcutaneous injection, or rectally. The bioavailability of oral administration of oxycodone averages within a range of 60 to 87%, with rectal administration yielding the same results; intranasal varies between individuals with a mean of 46%.


title: Oxycodone

text: After a dose of conventional (immediate-release) oral oxycodone, the onset of action is 10 to 30 minutes, and peak plasma levels of the drug are attained within roughly 30 to 60 minutes; in contrast, after a dose of OxyContin (an oral controlled-release formulation), peak plasma levels of oxycodone occur in about three hours. The duration of instant-release oxycodone is 3 to 6 hours, although this can be variable depending on the individual.


title: Oxycodone

text: Oxycodone has a volume of distribution of 2.6L/kg, in the blood it is distributed to skeletal muscle, liver, intestinal tract, lungs, spleen, and brain. At equilibrium the unbound concentration in the brain is threefold higher than the unbound concentration in blood Conventional oral preparations start to reduce pain within 10 to 15 minutes on an empty stomach; in contrast, OxyContin starts to reduce pain within one hour.


title: Oxycodone

text: The metabolism of oxycodone in humans occurs in the liver mainly via the cytochrome P450 system and is extensive (about 95%) and complex, with many minor pathways and resulting metabolites. Around 10% (range 8–14%) of a dose of oxycodone is excreted essentially unchanged (unconjugated or conjugated) in the urine. The major metabolites of oxycodone are noroxycodone (70%), noroxymorphone ("relatively high concentrations"), and oxymorphone (5%). The immediate metabolism of oxycodone in humans is as follows:


title: Oxycodone

text: In humans, N-demethylation of oxycodone to noroxycodone by CYP3A4 is the major metabolic pathway, accounting for 45% ± 21% of a dose of oxycodone, while O-demethylation of oxycodone into oxymorphone by CYP2D6 and 6-ketoreduction of oxycodone into 6-oxycodols represent relatively minor metabolic pathways, accounting for 11% ± 6% and 8% ± 6% of a dose of oxycodone, respectively.


title: Oxycodone

text: Several of the immediate metabolites of oxycodone are subsequently conjugated with glucuronic acid and excreted in the urine. 6α-Oxycodol and 6β-oxycodol are further metabolized by N-demethylation to nor-6α-oxycodol and nor-6β-oxycodol, respectively, and by N-oxidation to 6α-oxycodol-N-oxide and 6β-oxycodol-N-oxide (which can subsequently be glucuronidated as well). Oxymorphone is also further metabolized, as follows:


title: Oxycodone

text: The first pathway of the above three accounts for 40% of the metabolism of oxymorphone, making oxymorphone-3-glucuronide the main metabolite of oxymorphone, while the latter two pathways account for less than 10% of the metabolism of oxymorphone. After N-demethylation of oxymorphone, noroxymorphone is further glucuronidated to noroxymorphone-3-glucuronide.


title: Oxycodone

text: Because oxycodone is metabolized by the cytochrome P450 system in the liver, its pharmacokinetics can be influenced by genetic polymorphisms and drug interactions concerning this system, as well as by liver function. Some people are fast metabolizers of oxycodone, while others are slow metabolizers, resulting in polymorphism-dependent alterations in relative analgesia and toxicity. While higher CYP2D6 activity increases the effects of oxycodone (owing to increased conversion into oxymorphone), higher CYP3A4 activity has the opposite effect and decreases the effects of oxycodone (owing to increased metabolism into noroxycodone and noroxymorphone). The dose of oxycodone must be reduced in patients with reduced liver function.


title: Oxycodone

text: The clearance of oxycodone is 0.8 L/min. Oxycodone and its metabolites are mainly excreted in urine. Therefore, oxycodone accumulates in patients with kidney impairment. Oxycodone is eliminated in the urine 10% as unchanged oxycodone, 45% ± 21% as "N"-demethylated metabolites (noroxycodone, noroxymorphone, noroxycodols), 11 ± 6% as "O"-demethylated metabolites (oxymorphone, oxymorphols), and 8% ± 6% as 6-keto-reduced metabolites (oxycodols).


title: Oxycodone

text: Oxycodone has a half-life of 4.5 hours. It is available as a generic medication. The manufacturer of OxyContin, a controlled-release preparation of oxycodone, Purdue Pharma, claimed in their 1992 patent application that the duration of action of OxyContin is 12 hours in "90% of patients". It has never performed any clinical studies in which OxyContin was given at more frequent intervals. In a separate filing, Purdue claims that controlled-release oxycodone "provides pain relief in said patient for at least 12 hours after administration". However, in 2016 an investigation by the "Los Angeles Times" found that "the drug weans off hours early in many people", inducing symptoms of opiate withdrawal and intense cravings for OxyContin. One doctor, Lawrence Robbins, told journalists that over 70% of his patients would report that OxyContin would only provide 4–7 hours of relief. Doctors in the 1990s often would switch their patients to a dosing schedule of once every eight hours when they complained that the duration of action for OxyContin was too short to be taken only twice a day.


title: Oxycodone

text: Purdue strongly discouraged the practice: Purdue's medical director Robert Reder wrote to one doctor in 1995 that "OxyContin has been developed for [12-hour] dosing...I request that you not use a [8-hourly] dosing regimen." Purdue repeatedly released memos to its sales representatives ordering them to remind doctors not to deviate from a 12-hour dosing schedule. One such memo read, "There is no Q8 dosing with OxyContin... [8-hour dosing] needs to be nipped in the bud. NOW!!" The journalists who covered the investigation argued that Purdue Pharma has insisted on a 12-hour duration of action for nearly all patients, despite evidence to the contrary, to protect the reputation of OxyContin as a 12-hour drug and the willingness of health insurance and managed care companies to cover OxyContin despite its high cost relative to generic opiates such as morphine.


title: Oxycodone

text: Purdue sales representatives were instructed to encourage doctors to write prescriptions for larger 12-hour doses instead of more frequent dosing. An August 1996 memo to Purdue sales representatives in Tennessee entitled "$$$$$$$$$$$$$ It's Bonus Time in the Neighborhood!" reminded the representatives that their commissions would dramatically increase if they were successful in convincing doctors to prescribe larger doses. "Los Angeles Times" journalists argue using interviews from opioid addiction experts that such high doses of OxyContin spaced 12 hours apart create a combination of agony during opiate withdrawal (lower lows) and a schedule of reinforcement that relieves this agony, fostering addiction.


title: Oxycodone

text: Oxycodone's chemical name is derived from codeine. The chemical structures are very similar, differing only in that


title: Oxycodone

text: In terms of biosynthesis, oxycodone has been found naturally in nectar extracts from the orchid family "Epipactis helleborine"; together along with another opioid: 3-{2-{3-{3-benzyloxypropyl}-3-indol, 7,8-didehydro- 4,5-epoxy-3,6-d-morphinan.


title: Oxycodone

text: Thodey "et al.", 2014 introduces a microbial compound manufacturing system for compounds including oxycodone. The Thodey platform produces both natural and semisynthetic opioids including this one. This system uses "Saccharomyces cerevisiae" with transgenes from "Papaver somniferum" (the opium poppy) and "Pseudomonas putida" to turn a thebaine input into other opiates and opioids.


title: Oxycodone

text: Oxycodone and/or its major metabolites may be measured in blood or urine to monitor for clearance, non-medical use, confirm a diagnosis of poisoning, or assist in a medicolegal death investigation. Many commercial opiate screening tests cross-react appreciably with oxycodone and its metabolites, but chromatographic techniques can easily distinguish oxycodone from other opiates.


title: Oxycodone

text: Martin Freund and (Jakob) Edmund Speyer of the University of Frankfurt in Germany published the first synthesis of oxycodone from thebaine in 1916. When Freund died, in 1920, Speyer wrote his obituary. Speyer, born to a Jewish family in Frankfurt am Main in 1878, became a victim of the Holocaust. He died on 5 May 1942, the second day of deportations from the Lodz Ghetto; his death was noted in the ghetto's chronicle.


title: Oxycodone

text: The first clinical use of the drug was documented in 1917, the year after it was first developed. It was first introduced to the U.S. market in May 1939. In early 1928, Merck introduced a combination product containing scopolamine, oxycodone, and ephedrine under the German initials for the ingredients SEE, which was later renamed Scophedal (SCOpolamine, ePHEDrine, and eukodAL) in 1942. It was last manufactured in 1987, but can be compounded. This combination is essentially an oxycodone analogue of the morphine-based "twilight sleep", with ephedrine added to reduce circulatory and respiratory effects. The drug became known as the "Miracle Drug of the 1930s" in Continental Europe and elsewhere and it was the Wehrmacht's choice for a battlefield analgesic for a time. The drug was expressly designed to provide what the patent application and package insert referred to as "very deep analgesia and profound and intense euphoria" as well as tranquillisation and anterograde amnesia useful for surgery and battlefield wounding cases. Oxycodone was allegedly chosen over other common opiates for this product because it had been shown to produce less sedation at equianalgesic doses compared to morphine, hydromorphone (Dilaudid), and hydrocodone (Dicodid).


title: Oxycodone

text: During Operation Himmler, Skophedal was also reportedly injected in massive overdose into the prisoners dressed in Polish Army uniforms in the staged incident on 1 September 1939 which opened the Second World War.


title: Oxycodone

text: The personal notes of Adolf Hitler's physician, Theodor Morell, indicate Hitler received repeated injections of "Eukodal" (oxycodone) and Scophedal, as well as Dolantin (pethidine) codeine, and morphine less frequently; oxycodone could not be obtained after late January 1945.


title: Oxycodone

text: Purdue Pharma, a privately held company based in Stamford, Connecticut, developed the prescription painkiller OxyContin. It was approved by the FDA in 1995 after no long-term studies and no assessment of its addictive capabilities. David Kessler, FDA commissioner at the time, later said of the approval of OxyContin: “No doubt it was a mistake. It was certainly one of the worst medical mistakes, a major mistake.” Upon its release in 1995, OxyContin was hailed as a medical breakthrough, a long-lasting narcotic that could help patients with moderate to severe pain. The drug became a blockbuster, and has reportedly generated some US$35 billion in revenue for Purdue.


title: Oxycodone

text: Oxycodone, like other opioid analgesics, tends to induce feelings of euphoria, relaxation and reduced anxiety in those who are occasional users. These effects make it one of the most commonly abused pharmaceutical drugs in the United States. Diverted oxycodone may be taken orally or ingested through insufflation; used intravenously, or the heated vapors inhaled.


title: Oxycodone

text: Oxycodone is the most widely recreationally used opioid in America. In the United States, more than 12 million people use opioid drugs recreationally. The U.S. Department of Health and Human Services estimates that about 11 million people in the U.S. consume oxycodone in a non-medical way annually.


title: Oxycodone

text: Opioids were responsible for 49,000 of the 72,000 drug overdose deaths in the U.S. in 2017. In 2007, about 42,800 emergency room visits occurred due to "episodes" involving oxycodone. In 2008, recreational use of oxycodone and hydrocodone was involved in 14,800 deaths. Some of the cases were due to overdoses of the acetaminophen component, resulting in fatal liver damage.


title: Oxycodone

text: In September 2013, the FDA released new labeling guidelines for long acting and extended release opioids requiring manufacturers to remove moderate pain as indication for use, instead stating the drug is for "pain severe enough to require daily, around-the-clock, long term opioid treatment". The updated labeling will not restrict physicians from prescribing opioids for moderate, as needed use.


title: Oxycodone

text: Reformulated OxyContin is causing some recreational users to change to heroin, which is cheaper and easier to obtain.


title: Oxycodone

text: In October 2017, "The New Yorker" published a story on Mortimer Sackler and Purdue Pharma regarding their ties to the production and manipulation of the oxycodone markets. The article links Raymond and Arthur Sackler's business practices with the rise of direct pharmaceutical marketing and eventually to the rise of addiction to oxycodone in the United States. The article implies that the Sackler family bears some responsibility for the opioid epidemic in the United States. In 2019, "The New York Times" ran a piece confirming that Richard Sackler, the son of Raymond Sackler, told company officials in 2008 to "measure our performance by Rx's by strength, giving higher measures to higher strengths". This was verified with documents tied to a lawsuit – which was filed by the Massachusetts attorney general, Maura Healey – claiming that Purdue Pharma and members of the Sackler family knew that high doses of OxyContin over long periods would increase the risk of serious side effects, including addiction. Despite Purdue Pharma's proposal for a US$12 billion settlement of the lawsuit, the attorneys general of 23 states, including Massachusetts, rejected the settlement offer in September 2019.


title: Oxycodone

text: The non-medical use of oxycodone existed from the early 1970s, but by 2015, 91% of a national sample of injecting drug users in Australia had reported using oxycodone, and 27% had injected it in the last six months.


title: Oxycodone

text: Opioid-related deaths in Ontario had increased by 242% from 1969 to 2014. By 2009 in Ontario there were more deaths from oxycodone overdoses than from cocaine overdoses. Deaths from opioid pain relievers had increased from 13.7 deaths per million residents in 1991 to 27.2 deaths per million residents in 2004. The non-medical use of oxycodone in Canada became a problem. Areas where oxycodone is most problematic are Atlantic Canada and Ontario, where its non-medical use is prevalent in rural towns, and in many smaller to medium-sized cities. Oxycodone is also widely available across Western Canada, but methamphetamine and heroin are more serious problems in larger cities, while oxycodone is more common in rural towns. Oxycodone is diverted through doctor shopping, prescription forgery, pharmacy theft, and overprescription.


title: Oxycodone

text: The recent formulations of oxycodone, particularly Purdue Pharma's crush-, chew-, injection- and dissolve-resistant OxyNEO which replaced the banned OxyContin product in Canada in early 2012, have led to a decline in the recreational use of this opiate but have increased the recreational use of the more potent drug fentanyl. According to a Canadian Centre on Substance Abuse study quoted in Maclean's magazine, there were at least 655 fentanyl-related deaths in Canada in a five-year period.


title: Oxycodone

text: In Alberta, the Blood Tribe police claimed that from the fall of 2014 through January 2015, oxycodone pills or a lethal fake variation referred to as Oxy 80s containing fentanyl made in illegal labs by members of organized crime were responsible for ten deaths on the Blood Reserve, which is located southwest of Lethbridge, Alberta. Province-wide, approximately 120 Albertans died from fentanyl-related overdoses in 2014.


title: Oxycodone

text: Prescriptions of Oxycodone rose in Scotland by 430% between 2002 and 2008, prompting fears of usage problems that would mirror those of the United States. The first known death due to overdose in the UK occurred in 2002.


title: Oxycodone

text: In August 2010, Purdue Pharma reformulated their long-acting oxycodone line, marketed as OxyContin, using a polymer, Intac, to make the pills more difficult to crush or dissolve in water to reduce non-medical use of OxyContin. The FDA approved relabeling the reformulated version as abuse-resistant in April 2013.


title: Oxycodone

text: Pfizer manufactures a preparation of short-acting oxycodone, marketed as Oxecta, which contains inactive ingredients, referred to as tamper-resistant Aversion Technology. It does not deter oral recreational use. Approved by the FDA in the U.S. in June 2011, the new formulation makes crushing, chewing, snorting, or injecting the opioid impractical because of a change in its chemical properties.


title: Oxycodone

text: Oxycodone is subject to international conventions on narcotic drugs. In addition, oxycodone is subject to national laws that differ by country. The 1931 Convention for Limiting the Manufacture and Regulating the Distribution of Narcotic Drugs of the League of Nations included oxycodone. The 1961 Single Convention on Narcotic Drugs of the United Nations, which replaced the 1931 convention, categorized oxycodone in Schedule I. Global restrictions on Schedule I drugs include "limit[ing] exclusively to medical and scientific purposes the production, manufacture, export, import, distribution of, trade in, use and possession of" these drugs; "requir[ing] medical prescriptions for the supply or dispensation of [these] drugs to individuals"; and "prevent[ing] the accumulation" of quantities of these drugs "in excess of those required for the normal conduct of business".


title: Oxycodone

text: Oxycodone is in Schedule I (derived from the Single Convention on Narcotic Drugs) of the Commonwealth's Narcotic Drugs Act 1967. In addition, it is in Schedule 8 of the Australian Standard for the Uniform Scheduling of Drugs and Poisons ("Poisons Standard"), meaning it is a "controlled drug... which should be available for use but require[s] restriction of manufacture, supply, distribution, possession and use to reduce abuse, misuse and physical or psychological dependence".


title: Oxycodone

text: Oxycodone is a controlled substance under Schedule I of the Controlled Drugs and Substances Act (CDSA).


title: Oxycodone

text: In February 2012, Ontario passed legislation to allow the expansion of an already existing drug-tracking system for publicly funded drugs to include those that are privately insured. This database will function to identify and monitor patient's attempts to seek prescriptions from multiple doctors or retrieve them from multiple pharmacies. Other provinces have proposed similar legislation, while some, such as Nova Scotia, have legislation already in effect for monitoring prescription drug use. These changes have coincided with other changes in Ontario's legislation to target the misuse of painkillers and high addiction rates to drugs such as oxycodone. As of 29 February 2012, Ontario passed legislation delisting oxycodone from the province's public drug benefit program. This was a first for any province to delist a drug based on addictive properties. The new law prohibits prescriptions for OxyNeo except to certain patients under the Exceptional Access Program including palliative care and in other extenuating circumstances. Patients already prescribed oxycodone will receive coverage for an additional year for OxyNeo, and after that, it will be disallowed unless designated under the exceptional access program.