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133-543: (Redirected from P-4 ) P4 may refer to: Computing [ edit ] Intel Pentium 4 , a processor series shipped from 2000 to 2008 The P4 power connector, introduced in the ATX12V 1.0 standard to power these and later CPUs The i486DX (P4) model of the Intel 80486 microprocessor, introduced in 1989 P4 (programming language) , for controlling network data forwarding P4,

266-489: A TDP of 86 W. The D0 stepping in late 2006 reduced this to 65 watts. It has a 65 nm core and features the same 31-stage pipeline as Prescott, 800 MT/s FSB, Intel 64 , Hyper-Threading , but no Virtualization Technology. As with Prescott 2M, Cedar Mill also has a 2 MB L2 cache. Intel initially announced four VT-x enabled Cedar Mill processors with model numbers 633 to 663, but these were later cancelled and replaced by models 631 to 661 without VT-x,

399-457: A buffer overflow to get executed. Models supporting XD bit include the 5x0J and 5x1 series as well as the low-end 5x5J and 5x6. The Prescott processors are the first to support SSE3 , along with all Pentium D processors. Intel, by the first quarter of 2005, released a new Prescott core with 6x0 numbering, codenamed Prescott 2M. It is also sometimes known by the name of its Xeon derivative, Irwindale. It features Hyper-Threading, Intel 64 ,

532-605: A Pentium 4 580, clocked at 4 GHz. The E-series Prescott, as well as the low-end 517 and 524, incorporates Hyper-Threading in order to speed up some processes that use multithreaded software, such as video editing. The Prescott microarchitecture was designed to support Intel 64, Intel's implementation of the AMD-developed x86-64 64-bit extensions to the x86 architecture, but the initial models shipped with their 64-bit capability disabled. Intel stated that it did not intend to release 64-bit CPUs in retail channels, instead releasing

665-401: A Swedish army unit, designated P 4 Peugeot P4 , a French military vehicle Science [ edit ] P4 laboratory , a biosafety level 4 facility Tetraphosphorus (P 4 ), an allotrope of phosphorus Group p4, the plane symmetry group wallpaper group p 4 Progesterone (Pregn-4-ene-3,20-dione), a steroid hormone Kerberos , the fourth moon of Pluto Perfect fourth ,

798-402: 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

931-466: A chip (SoC). 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

1064-446: 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. 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

1197-458: 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. Modern CPUs typically contain more than one ALU to improve performance. The address generation unit (AGU), sometimes also called the address computation unit (ACU), is an execution unit inside the CPU that calculates addresses used by

1330-458: 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

1463-399: A free trade agreement between Brunei, Chile, New Zealand, and Singapore Prussian P 4 , a German steam locomotive Protofour , or P4, a set of standards for model railways See also [ edit ] 4P (disambiguation) Phosphate , molecular formula PO 4 Play (telecommunications) P4, a Polish cellular telecommunications provider [REDACTED] Topics referred to by

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1596-555: A global clock signal. Two notable examples of this are the ARM compliant AMULET and the MIPS R3000 compatible MiniMIPS. 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

1729-460: 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

1862-543: A maximum of 3.8 GHz. Intel had not anticipated a rapid upward scaling of transistor power leakage that began to occur as the die reached the 90 nm lithography and smaller. This new power leakage phenomenon, along with the standard thermal output, created cooling and clock scaling problems as clock speeds increased. Reacting to these unexpected obstacles, Intel attempted several core redesigns ( Prescott most notably) and explored new manufacturing technologies, such as using multiple cores, increasing FSB speeds, increasing

1995-411: 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. 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

2128-529: A modest but respectable rate, handicapped somewhat by the requirement for relatively fast yet expensive Rambus Dynamic RAM ( RDRAM ). The Pentium III remained Intel's top selling processor line, with the Athlon also selling slightly better than the Pentium 4. While Intel bundled two RDRAM modules with each boxed Pentium 4, it did not facilitate Pentium 4 sales and was not considered a true solution by many. In January 2001,

2261-504: A musical interval Enterobacteria phage P4 P4, an EEG electrode site according to the 10-20 system P4 cell, a stage in the Caenorhabditis elegans embryonic development P4-metric , in statistics, a performance metric Roads [ edit ] P4 road (Latvia) P04 road (Ukraine) Other uses [ edit ] Papyrus 4 , a New Testament manuscript Trans-Pacific Strategic Economic Partnership , or P4,

2394-494: A new core codenamed Northwood at speeds of 1.6 GHz, 1.8 GHz, 2 GHz and 2.2 GHz. Northwood (product code 80532) combined an increase in the L2 cache size from 256 KB to 512 KB (increasing the transistor count from 42 million to 55 million) with a transition to a new 130 nm fabrication process. Making the processor out of smaller transistors means that it can run at higher clock speeds and produce less heat. In

2527-456: 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

2660-412: A shared unidirectional bus. The NetBurst microarchitecture consumed more power and emitted more heat than any previous Intel or AMD microarchitectures. As a result, the Pentium 4's introduction was met with mixed reviews: Developers disliked the Pentium 4, as it posed a new set of code optimization rules. For example, in mathematical applications, AMD's lower-clocked Athlon (the fastest-clocked model

2793-416: A single IC chip. Microprocessor chips with multiple CPUs are called multi-core processors . The individual physical CPUs, called processor cores , can also be multithreaded to support CPU-level multithreading. 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

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2926-474: A still slower 1.3 GHz model was added to the range, but over the next twelve months, Intel gradually started reducing AMD's leadership in performance. In April 2001 a 1.7 GHz Pentium 4 was launched, the first model to provide performance clearly superior to the old Pentium III. July saw 1.6 and 1.8 GHz models and in August 2001, Intel released 1.9 and 2 GHz Pentium 4s. In the same month, they released

3059-478: A targeted speed boost the double size cache was intended to provide the same space and hence performance for 64-bit mode operations, due to the doubled word size compared to 32-bit mode. On November 14, 2005, Intel released Prescott 2M processors with VT ( Virtualization Technology, codenamed Vanderpool) enabled. Intel only released two models of this Prescott 2M category: 662 and 672, running at 3.6 GHz and 3.8 GHz, respectively. The final revision of

3192-554: 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. Many microprocessors (in smartphones and desktop, laptop, server computers) have

3325-446: 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—such as 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

3458-439: 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

3591-525: Is also known as organosilicate glass (OSG). The Prescott was first fabricated at the D1C development fab and was later moved to F11X production fab. Originally, Intel released two Prescott lines on Socket 478: the E-series, with an 800 MT/s FSB and Hyper-Threading support, and the low-end A-series, with a 533 MT/s FSB and Hyper-Threading disabled. LGA 775 Prescott CPUs use a rating system, labeling them as

3724-400: 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

3857-459: Is different from Wikidata All article disambiguation pages All disambiguation pages Intel Pentium 4 Pentium 4 is a series of single-core CPUs for desktops , laptops and entry-level servers manufactured by Intel . The processors were shipped from November 20, 2000 until August 8, 2008. All Pentium 4 CPUs are based on the NetBurst microarchitecture, the successor to

3990-418: Is difficult to quantify due to dependence on the benchmark application's instruction mix, clock speed is a simple measurement yielding a single absolute number. Unsophisticated buyers would simply consider the processor with the highest clock speed to be the best product, and the Pentium 4 had the fastest clock speed. Because AMD's processors had slower clock speeds, it countered Intel's marketing advantage with

4123-494: 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. 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

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4256-432: Is greater or whether they are equal; one of these flags could then be used by a later jump instruction to determine program flow. 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

4389-400: Is largely addressed in modern processors by caches and pipeline architectures (see below). 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. The way in which the instruction is interpreted

4522-524: 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

4655-723: Is the IBM PowerPC -based Xenon used in the Xbox 360 ; this reduces the power requirements of the Xbox 360. 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

4788-599: The "E0" revision of the Prescotts, being sold on the OEM market as the Pentium 4, model F. The E0 revision also adds eXecute Disable (XD) (Intel's name for the NX bit ) to Intel 64. Intel's official launch of Intel 64 (under the name EM64T at that time) in mainstream desktop processors was the N0 stepping Prescott-2M. Intel also marketed a version of their low-end Celeron processors based on

4921-626: The 845 chipset that supported much cheaper PC133 SDRAM instead of RDRAM. The fact that SDRAM was so much cheaper caused the Pentium 4's sales to grow considerably. The new chipset allowed the Pentium 4 to quickly replace the Pentium III, becoming the top-selling mainstream processor on the market. The Willamette code name is derived from the Willamette Valley region of Oregon, where a large number of Intel 's manufacturing facilities are located. In January 2002, Intel released Pentium 4s with

5054-662: The Allendale (and later Conroe ) desktop processors and in late 2007 with the Merom mobile processors, with the underlying microarchitecture being the Core microarchitecture . Central processing unit 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

5187-485: The IBM z13 has a 96 KiB L1 instruction cache. 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,

5320-518: The P6 and NetBurst microarchitectures, Intel could not market Willamette as a Pentium III, so it was marketed as the Pentium 4. On November 20, 2000, Intel released the Willamette-based Pentium 4 clocked at 1.4 and 1.5 GHz. Most industry experts regarded the initial release as a stopgap product, introduced before it was truly ready. According to these experts, the Pentium 4 was released because

5453-513: The P6 . The Pentium 4 Willamette (180 nm) introduced SSE2 , while the Prescott (90 nm) introduced SSE3 and later 64-bit technology. Later versions introduced Hyper-Threading Technology (HTT). The first Pentium 4-branded processor to implement 64-bit was the Prescott (90 nm) (February 2004), but this feature was not enabled. Intel subsequently began selling 64-bit Pentium 4s using

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5586-554: The Perforce software command line client Media [ edit ] P4 Radio Hele Norge (PFI), a Norwegian radio company Kanal 24 (Kanal 4), which acquired the Norwegian P4 channel from PFI Sveriges Radio P4 , a Swedish radio channel Persona 4 , a 2008 video game Periphery IV: Hail Stan , 2019 album by American progressive metal band Periphery Military [ edit ] Skaraborg Regiment (armoured) ,

5719-474: 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.). All modern (fast) CPUs (with few specialized exceptions ) have multiple levels of CPU caches. The first CPUs that used

5852-466: The " megahertz myth " campaign. AMD product marketing used a " PR-rating " system, which assigned a merit value based on relative performance to a baseline machine. At the launch of the Pentium 4, Intel stated that NetBurst-based processors were expected to scale to 10 GHz after several fabrication process generations. However, the clock speed of processors using the NetBurst microarchitecture reached

5985-570: The 2.26 GHz, 2.4 GHz, and 2.53 GHz models in May, 2.66 GHz and 2.8 GHz models in August, and 3.06 GHz model in November. With Northwood, the Pentium 4 came of age. The battle for performance leadership remained competitive (as AMD introduced faster versions of the Athlon XP) but most observers agreed that the fastest-clocked Northwood-based Pentium 4 was usually ahead of its rival. This

6118-550: The 5xx series (Celeron Ds are the 3xx series, while Pentium Ms are the 7xx series). The LGA 775 version of the E-series uses model numbers 5x0 (520–560), and the LGA 775 version of the A-series uses model numbers 5x5 and 5x9 (505–519). The fastest, the 570J and 571, is clocked at 3.8 GHz. Plans to mass-produce a 4 GHz Pentium 4 were cancelled by Intel in favor of dual core processors, although some European retailers claimed to be selling

6251-486: The 64-bit capable F-series to OEMs only. However, they were later made available to the general public as the 5x1 series. A number of low-end Intel 64-enabled Prescotts, with 533 MHz FSB speed, were also released. The E0 stepping of the Prescott series introduced the XD bit feature. This technology, introduced to the x86 architecture by AMD as NX (No eXecute) , can help prevent certain types of malicious code from exploiting

6384-446: The 90 nm and 65 nm parts respectively. The original successor to the Pentium 4 was (codenamed) Tejas , which was scheduled for an early-mid-2005 release. However, it was cancelled a few months after the release of Prescott due to extremely high TDPs (a 2.8 GHz Tejas emitted 150 W of heat, compared to around 80 W for a Northwood of the same speed, and 100 W for a comparably clocked Prescott) and development on

6517-450: 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. 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

6650-546: 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. Modern CPUs devote a lot of semiconductor area to caches and instruction-level parallelism to increase performance and to CPU modes to support operating systems and virtualization . Most modern CPUs are implemented on integrated circuit (IC) microprocessors , with one or more CPUs on

6783-431: The ALU's output word size), an arithmetic overflow flag will be set, influencing the next operation. 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

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6916-613: The Athlon XP architecture was less dependent on bandwidth, the bandwidth numbers reached by Intel were well out of range for the Athlon's EV6 bus. Hypothetically, EV6 could have achieved the same bandwidth numbers, but only at speeds unreachable at the time. Intel's higher bandwidth proved useful in benchmarks for streaming operations , and Intel marketing wisely capitalized on this as a tangible improvement over AMD's desktop processors . Northwood 2.4 GHz, 2.6 GHz and 2.8 GHz variants were released on May 21, 2003. A 3.2 GHz variant

7049-468: 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

7182-479: 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. 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

7315-422: 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

7448-467: The CPU to require more heat dissipation in the form of CPU cooling solutions. 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

7581-411: The CPU was released using the new Socket 775 ( LGA 775 ). A slight performance increase was achieved in late 2004 by increasing the bus speed from 800 MT/s to 1066 MT/s, resulting in a 3.46 GHz Pentium 4 Extreme Edition. By most metrics, this was on a per-clock basis the fastest single-core NetBurst processor that was ever produced, even outperforming many of its successor chips (not counting

7714-514: The IHS, a CPU shim was some times used by people worried about damaging the core. Overclockers sometimes removed the IHS from Socket 423 and Socket 478 chips to allow for more direct heat transfer. On Socket 478 Prescott processors and processors using the Socket LGA 775 (Socket T) interface, the IHS is directly soldered to the die or dies, making it difficult to remove. Willamette, the project codename for

7847-452: The NetBurst microarchitecture (often referred to as Celeron 4 ), and a high-end derivative, Xeon , intended for multi-socket servers and workstations. In 2005, the Pentium 4 was complemented by the more advanced dual-core -brands Pentium D and Pentium Extreme Edition, all were succeeded at the top range by the Core 2 brand, while production continued until 2008, with Pentium 4 replaced by Pentium Dual-Core . In benchmark evaluations,

7980-773: The NetBurst microarchitecture as a whole ceased, with the exception of the dual-core Pentium D, Pentium Extreme Edition and the Cedar Mill-based Pentium 4 HT. The real successor to the Pentium 4 brand is the Pentium Dual-Core brand, released in 2006. The first chips implementing it (in 65 nm) were released in January 2007 with the Yonah mobile processors and are based on the Enhanced Pentium M architecture, in June 3, 2007 with

8113-512: The Pentium 4 M, the mobile version of the Pentium 4, was discontinued after suffering from heat and power consumption problems and was replaced by the Pentium M . The Pentium M was part of the Intel Centrino platform-marketing brand. In May 2005, Intel released dual-core processors under the Pentium D and Pentium Extreme Edition brands. These came under the code names Smithfield and Presler for

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8246-462: The Pentium 4 processor is significantly more complex than any previous IA-32 microprocessor, so the challenge of validating the logical correctness of the design in a timely fashion was indeed a daunting one." He hired a team of 60 recent graduates to help with testing and validation. Pentium 4 processors have an integrated heat spreader (IHS) that prevents the die from accidentally being damaged when mounting and unmounting cooling solutions. Prior to

8379-479: The Pentium 4 was Cedar Mill , released on January 5, 2006. This was a die shrink of the Prescott-based 600 series core to 65 nm , with no real feature additions but significantly reduced power consumption. The Cedar Mill is closely linked to the Pentium D Presler revision, with each Presler CPU consisting of two Cedar Mill cores on the same chip package. Cedar Mill had a lower heat output than Prescott, with

8512-514: The Pentium 4's singular emphasis on clock frequency (above all else) made it a marketer's dream. The result of this was that the NetBurst microarchitecture was often referred to as a marchitecture by various computing websites and publications during the life of the Pentium 4. It was also called "NetBust", a term popular with reviewers who reflected negatively upon the processor's performance. The two classical metrics of CPU performance are instructions per cycle (IPC) and clock speed . While IPC

8645-525: The Socket 775/LGA 775 versions of the Pentium 4 Extreme Edition, as well as the Pentium Extreme Edition (Smithfield) and Engineering Sample CPUs have unlocked multipliers. On February 1, 2004, Intel introduced a new core codenamed Prescott. The core used the 90 nm process for the first time, which one analyst described as "a major reworking of the Pentium 4's microarchitecture." Despite this overhaul,

8778-456: The XD ;bit, EIST (Enhanced Intel SpeedStep Technology), Thermal Monitor 2 (for processors at 3.6 GHz and above), and 2 MB of L2 cache. However, AnandTech found that this resulted in 17% higher cache latency compared to Prescott, which combined with the lack of consumer-targeted programs requiring more cache, largely negated the advantage that added cache introduced. Rather than being

8911-400: The advantages of the NetBurst microarchitecture were unclear. With carefully optimized application code, the first Pentium 4s outperformed Intel's fastest Pentium III (clocked at 1.13 GHz at the time), as expected. But in legacy applications with many branching or x87 floating-point instructions, the Pentium 4 would merely match or run slower than its predecessor. Its main downfall was

9044-431: 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. 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

9177-450: The advent of the stored-program computer . The idea of a stored-program computer had been already present in the design of John 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 a paper entitled First Draft of a Report on the EDVAC . It was

9310-428: 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. In 1964, IBM introduced its IBM System/360 computer architecture that

9443-516: The cache size, and using a longer instruction pipeline along with higher clock speeds. The code cache was replaced by a trace cache which contained decoded microoperations rather than instructions with advantage of eliminating instruction decoding bottleneck so that the design can use RISC technology. This came with a disadvantage of less compact cache taking up more chip space and consuming power. These solutions failed, and from 2003 to 2005, Intel shifted development away from NetBurst to focus on

9576-497: The competing Thunderbird-based AMD Athlon was outperforming the aging Pentium III, and further improvements to the Pentium III were not yet possible. This Pentium 4 was produced using a 180 nm process and initially used Socket 423 (also called socket W, for "Willamette"), with later revisions moving to Socket 478 (socket N, for "Northwood"). These variants were identified by the Intel product codes 80528 and 80531 respectively. On

9709-564: 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. 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

9842-423: The complexity scale, a machine language program is a collection of machine language instructions that the CPU executes. 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

9975-486: 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. 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

10108-516: The cooler-running Pentium M microarchitecture. On January 5, 2006, Intel launched the Core processors, which put greater emphasis on energy efficiency and performance per clock cycle. The final NetBurst-derived products were released in 2007, with all subsequent product families switching exclusively to the Core microarchitecture. According to Bob Bentley, presenting on behalf of Intel at the 38th annual Design Automation Conference, "The microarchitecture of

10241-453: 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 . For example, if an instruction that performs addition is to be executed, registers containing operands (numbers to be summed) are activated, as are

10374-427: The desktop Pentium 4, the Pentium 4 M did not feature an integrated heat spreader (IHS), and it operates at a lower voltage. The lower voltage means lower power consumption, and in turn less heat. However, according to Intel specifications, the Pentium 4 M had a maximum thermal junction temperature rating of 100 degrees C, approximately 40 degrees higher than the desktop Pentium 4. The Mobile Intel Pentium 4 Processor

10507-429: 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

10640-536: The dual-core Pentium D ), the Core 2 Extreme , the Core i7 and the Core i9 . Contrary to popular belief, however, the Socket 478 versions of the Pentium 4 Extreme Edition CPUs such as the Gallatin-based Pentium 4 Extreme Edition for Socket 478 all have a locked multiplier, meaning that they are not overclockable unless the front-side bus speeds are increased (which runs the potential risks of erratic behaviors such as reliability and stability issues). Only

10773-401: The dual-core Pentium D). Afterwards, the Pentium 4 Extreme Edition was migrated to the Prescott core. The new 3.73 GHz Extreme Edition had the same features as a 6x0-sequence Prescott 2M, but with a 1066 MT/s bus. In practice however, the 3.73 GHz Pentium 4 Extreme Edition almost always proved to be slower than the 3.46 GHz Pentium 4 Extreme Edition, which is most likely due to

10906-453: 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. As the microelectronic technology advanced, an increasing number of transistors were placed on ICs, decreasing

11039-578: The era of specialized supercomputers like those made by Cray Inc and Fujitsu Ltd . 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

11172-503: 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

11305-510: The extra 1 added to the model number distinguishing them from the 90 nm Prescott cores operating at the same frequencies. Cedar Mill processors ranged in frequency from 3.0 to 3.6 GHz, down from the 3.8 GHz maximum of the Prescott-based 670 and 672. Overclockers managed to exceed 8 GHz with these processors using liquid nitrogen cooling. The name "Cedar Mill" refers to Cedar Mill, Oregon , an unincorporated community near Intel's Hillsboro, Oregon facilities. In March 2003,

11438-401: The faster the clock, the more instructions the CPU will execute each second. 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

11571-583: The first NetBurst microarchitecture implementation, experienced long delays in the completion of its design process. The project was started in 1998, when Intel saw the Pentium II as their permanent line. At that time, the Willamette core was expected to operate at frequencies up to about 1 GHz. However, the Pentium III was released while Willamette was still being finished. Due to the radical differences between

11704-555: 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. 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

11837-405: The lack of an L3 cache and the longer instruction pipeline. The only advantage the 3.73 GHz Pentium 4 Extreme Edition had over the 3.46 GHz Pentium 4 Extreme Edition was the ability to run 64-bit applications since all Gallatin-based Pentium 4 Extreme Edition processors lacked the Intel 64 (then known as EM64T) instruction set. Although never a particularly good seller, especially since it

11970-479: The launch of the Athlon XP 3200+ in AMD's desktop line, AMD increased the Athlon XP's FSB speed from 333 MT/s to 400 MT/s, but it was not enough to hold off the new 3 GHz Pentium 4 HT. The Pentium 4 HT's increase to a 200 MHz quad-pumped bus (200 x 4 = 800 MHz effective) greatly helped to satisfy the bandwidth requirements the NetBurst architecture desired for reaching optimal performance. While

12103-439: 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 use of parallelism and other methods that extend

12236-408: The location of a value that may be a processor register or a memory address, as determined by some addressing mode . 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

12369-406: 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

12502-421: The memory that stores the microprogram is rewritable, making it possible to change the way in which the CPU decodes instructions. 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

12635-463: The mobile Pentium 4 to bridge the gap between the desktop Pentium 4 (up to 115 W TDP), and the Pentium 4 M (up to 35 W TDP). Intel's naming conventions made it difficult at the time of the processor's release to identify the processor model. There was the Pentium III mobile chip, the Pentium 4 M, the Mobile Pentium 4, and then the Pentium M , which itself was based on the Pentium III and

12768-429: The night of 16–17 June 1949. 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

12901-507: The non-FX version) led to it usually being seen as the better value proposition. Nonetheless, the Extreme Edition did achieve Intel's apparent aim, which was to prevent AMD from being the performance champion with the new Athlon 64, which was winning every single major benchmark over the existing Pentium 4s. In January 2004, a 3.4 GHz version was released for Socket 478, and in Summer 2004

13034-706: 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. 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,

13167-567: 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. 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

13300-400: 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

13433-409: 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

13566-543: The performance gains were inconsistent. Some programs benefited from Prescott's doubled cache and SSE3 instructions, whereas others were harmed by its longer pipeline. The Prescott's microarchitecture allowed slightly higher clock speeds, but not nearly as high as Intel had anticipated. The fastest mass-produced Prescott-based Pentium 4s were clocked at 3.8 GHz. While Northwood ultimately achieved clock speeds 70% higher than Willamette, Prescott only scaled 12% beyond Northwood. Prescott's inability to achieve greater clock speeds

13699-501: 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. While von Neumann

13832-473: The possible exception of the last level. Each extra level of cache tends to be bigger and is optimized differently. 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. Caches are generally sized in powers of two: 2, 8, 16 etc. KiB or MiB (for larger non-L1) sizes, although

13965-448: 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. 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

14098-478: 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. The design complexity of CPUs increased as various technologies facilitated the building of smaller and more reliable electronic devices. The first such improvement came with

14231-409: The result to memory. Besides 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). The control unit (CU) is a component of the CPU that directs the operation of

14364-484: 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). However, architectural improvements alone do not solve all of

14497-499: The same Gallatin core as the Xeon MP, though in a Socket 478 form factor (as opposed to Socket 603 for the Xeon MP) and with an 800 MT/s bus, twice as fast as that of the Xeon MP. While Intel maintained that the Extreme Edition was aimed at gamers, critics viewed it as an attempt to steal the Athlon 64's launch thunder, nicknaming it the "Emergency Edition". With a price tag of $ 1000, it

14630-412: The same month boards utilizing the 845 chipset were released with enabled support for DDR SDRAM which provided double the bandwidth of PC133 SDRAM, and alleviated the associated high costs of using Rambus RDRAM for maximal performance with Pentium 4. A 2.4 GHz Pentium 4 was released on April 2, 2002, and the bus speed increased from 400  MT/s to 533 MT/s (133 MHz physical clock) for

14763-447: The same term This disambiguation page lists articles associated with the same title formed as a letter–number combination. If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=P4&oldid=1139447932 " Category : Letter–number combination disambiguation pages Hidden categories: Short description

14896-461: The same time on the same physical processor. By shuffling two (ideally differing) program instructions to simultaneously execute through a single physical processor core, the goal is to best utilize processor resources that would have otherwise been unused from the traditional approach of having these single instructions wait for each other to execute singularly through the core. This initial 3.06 GHz 533FSB Pentium 4 Hyper-Threading enabled processor

15029-540: 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

15162-570: The sole purpose of managing the Prescott's heat output at the expense of other components and concerns, such as blowing hot air from the CPU directly into the graphics card's heatsink/fan. These magnified the perception of Prescott as an excessively hot chip. The Prescott Pentium 4 contains 125 million transistors and has a die area of 112 mm . It was fabricated in a 90 nm process with seven levels of copper interconnect . The process has features such as strained silicon transistors and low-κ carbon-doped silicon oxide (CDO) dielectric, which

15295-448: The test bench, the Willamette was somewhat disappointing to analysts in that not only was it unable to outperform the Athlon and the highest-clocked Pentium IIIs in all testing situations, but it was not superior to the budget segment's AMD Duron . Although introduced at prices of $ 644 (1.4 GHz) and $ 819 (1.5 GHz) for 1000 quantities to OEM PC manufacturers (prices for models for the consumer market varied by retailer), it sold at

15428-422: 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

15561-431: The usefulness of the classical von Neumann model. 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 . After

15694-606: 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. Relays and vacuum tubes (thermionic tubes) were commonly used as switching elements;

15827-426: Was also referred to as the "Expensive Edition" and "Extremely Expensive". The added cache generally resulted in a noticeable performance increase in most processor intensive applications. Multimedia encoding and certain games benefited the most, with the Extreme Edition outperforming the Pentium 4, and even the two Athlon 64 variants, although the lower price and more balanced performance of the Athlon 64 (particularly

15960-482: Was attributed to the very high power consumption and heat output of the processor. This led to the processor receiving the nickname "PresHot" on forums. In fact, Prescott's power and heat characteristics were only slightly higher than those of Northwood of the same speed and nearly equal to the Gallatin-based Extreme Editions, but since those processors had already been operating near the limits of what

16093-522: Was caused by electromigration . Also based on the Northwood core, the Mobile Intel Pentium 4 Processor - M (also known as the Pentium 4 M ) was released on April 23, 2002, and included Intel's SpeedStep and Deeper Sleep technologies. Its TDP is about 35 watts in most applications. This lowered power consumption was due to lowered core voltage, and other features mentioned previously. Unlike

16226-442: Was clocked at 1.2 GHz at the time) easily outperformed the Pentium 4, which would only catch up if software was re-compiled with SSE2 support. Tom Yager of Infoworld magazine called it "the fastest CPU – for programs that fit entirely in cache". Computer-savvy buyers avoided Pentium 4 PCs due to their price premium, questionable benefit, and initial restriction to Rambus' RDRAM . In terms of product marketing,

16359-458: Was considered thermally acceptable, this still posed a major issue. The release of Prescott also coincided with the launch of LGA 775 and the BTX form factor , which were also criticized. Tests showed that a given Pentium 4 made for LGA 775 consumed more power and produced more heat than the exact same chip in a socket 478 package. The BTX form factor, meanwhile, showed signs of having been designed for

16492-412: Was known as Pentium 4 HT and was introduced to mass market by Gateway in November 2002. On April 14, 2003, Intel officially launched the new Pentium 4 HT processor. This processor used an 800 MT/s FSB (200 MHz physical clock), was clocked at 3 GHz, and had Hyper-Threading technology. This was meant to help the Pentium 4 better compete with AMD's Opteron line of processors. Meanwhile, with

16625-547: Was launched on June 23, 2003 and the final 3.4 GHz version arrived on February 2, 2004. Overclocking early stepping Northwood cores yielded a startling phenomenon. While core voltage approaching 1.7 V and above would often allow substantial additional gains in overclocking headroom, the processor would slowly (over several months or even weeks) become more unstable over time with a degradation in maximum stable clock speed before dying and becoming totally unusable. This became known as Sudden Northwood Death Syndrome (SNDS), which

16758-549: Was particularly so in mid-2002, when AMD's changeover to its 130 nm production process did not help the initial "Thoroughbred A" revision Athlon XP CPUs to clock high enough to overcome the advantages of Northwood in the 2.4 to 2.8 GHz range. The 3.06 GHz Pentium 4 enabled Hyper-Threading Technology that was first supported in Foster-based Xeons. This began the convention of virtual processors (or virtual cores) under x86 by enabling multiple threads to be run at

16891-512: Was released in a time when AMD was asserting near total dominance in the processor performance race, the Pentium 4 Extreme Edition established a new position within Intel's product line, that of an enthusiast oriented chip with the highest-end specifications offered by Intel chips, along with unlocked multipliers to allow for easier overclocking. In this role it has since been succeeded by the Pentium Extreme Edition (The Extreme version of

17024-564: Was released to address the problem of putting a full desktop Pentium 4 processor into a laptop, which some manufacturers were doing . The Mobile Pentium 4 used a 533 MT/s FSB, following the desktop Pentium 4's evolution. Oddly, increasing the bus speed by 133 MT/s (33 MHz) caused a massive increase in TDPs, as mobile Pentium 4 processors emitted 59.8–70 W of heat, with the Hyper-Threading variants emitting 66.1–88 W. This allowed

17157-477: Was significantly faster and more power-efficient than the former three. In September 2003, at the Intel Developer Forum, the Pentium 4 Extreme Edition (P4EE) was announced, just over a week before the launch of Athlon 64 and Athlon 64 FX . The design was mostly identical to Pentium 4 (to the extent that it would run in the same motherboards), but differed by an added 2 MB of level 3 cache. It shared

17290-640: Was so popular that it dominated the mainframe computer market for decades and left a legacy that is 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 . 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

17423-399: 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

17556-559: 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

17689-429: Was used in a series of computers capable of running the same programs with different speeds and performances. 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 use in modern CPUs. The System/360 architecture

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