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Cache coherence

In computer architecture, cache coherence is the uniformity of shared resource data that ends up stored in multiple local caches. When clients in a system maintain caches of a common memory resource, problems may arise with incoherent data, which is particularly the case with CPUs in a multiprocessing system.

In the illustration on the right, consider both the clients have a cached copy of a particular memory block from a previous read. Suppose the client on the bottom updates/changes that memory block, the client on the top could be left with an invalid cache of memory without any notification of the change. Cache coherence is intended to manage such conflicts by maintaining a coherent view of the data values in multiple caches.

Overview
In a shared memory multiprocessor system with a separate cache memory for each processor, it is possible to have many copies of shared data: one copy in the main memory and one in the local cache of each processor that requested it. When one of the copies of data is changed, the other copies must reflect that change. Cache coherence is the discipline which ensures that the changes in the values of shared operands (data) are propagated throughout the system in a timely fashion.

The following are the requirements for cache coherence: Theoretically, coherence can be performed at the load/store granularity. However, in practice it is generally performed at the granularity of cache blocks.
 * Write Propagation: Changes to the data in any cache must be propagated to other copies (of that cache line) in the peer caches.
 * Transaction Serialization: Reads/Writes to a single memory location must be seen by all processors in the same order.

Definition
Coherence defines the behavior of reads and writes to a single address location.

One type of data occurring simultaneously in different cache memory is called cache coherence, or in some systems, global memory.

In a multiprocessor system, consider that more than one processor has cached a copy of the memory location X. The following conditions are necessary to achieve cache coherence: The above conditions satisfy the Write Propagation criteria required for cache coherence. However, they are not sufficient as they do not satisfy the Transaction Serialization condition. To illustrate this better, consider the following example:
 * 1) In a read made by a processor P to a location X that follows a write by the same processor P to X, with no writes to X by another processor occurring between the write and the read instructions made by P, X must always return the value written by P.
 * 2) In a read made by a processor P1 to location X that follows a write by another processor P2 to X, with no other writes to X made by any processor occurring between the two accesses and with the read and write being sufficiently separated, X must always return the value written by P2. This condition defines the concept of coherent view of memory. Propagating the writes to the shared memory location ensures that all the caches have a coherent view of the memory. If processor P1 reads the old value of X, even after the write by P2, we can say that the memory is incoherent.

A multi-processor system consists of four processors - P1, P2, P3 and P4, all containing cached copies of a shared variable S whose initial value is 0. Processor P1 changes the value of S (in its cached copy) to 10 following which processor P2 changes the value of S in its own cached copy to 20. If we ensure only write propagation, then P3 and P4 will certainly see the changes made to S by P1 and P2. However, P3 may see the change made by P1 after seeing the change made by P2 and hence return 10 on a read to S. P4 on the other hand may see changes made by P1 and P2 in the order in which they are made and hence return 20 on a read to S. The processors P3 and P4 now have an incoherent view of the memory.

Therefore, in order to satisfy Transaction Serialization, and hence achieve Cache Coherence, the following condition along with the previous two mentioned in this section must be met: The alternative definition of a coherent system is via the definition of sequential consistency memory model: "the cache coherent system must appear to execute all threads’ loads and stores to a single memory location in a total order that respects the program order of each thread". Thus, the only difference between the cache coherent system and sequentially consistent system is in the number of address locations the definition talks about (single memory location for a cache coherent system, and all memory locations for a sequentially consistent system).
 * Writes to the same location must be sequenced. In other words, if location X received two different values A and B, in this order, from any two processors, the processors can never read location X as B and then read it as A. The location X must be seen with values A and B in that order.

Another definition is: "a multiprocessor is cache consistent if all writes to the same memory location are performed in some sequential order".

Rarely, but especially in algorithms, coherence can instead refer to the locality of reference. Multiple copies of same data can exist in different cache simultaneously and if processors are allowed to update their own copies freely, an inconsistent view of memory can result.

Coherence mechanisms
The two most common mechanisms of ensuring coherency are snooping and directory-based, each having their own benefits and drawbacks. Snooping based protocols tend to be faster, if enough bandwidth is available, since all transactions are a request/response seen by all processors. The drawback is that snooping isn't scalable. Every request must be broadcast to all nodes in a system, meaning that as the system gets larger, the size of the (logical or physical) bus and the bandwidth it provides must grow. Directories, on the other hand, tend to have longer latencies (with a 3 hop request/forward/respond) but use much less bandwidth since messages are point to point and not broadcast. For this reason, many of the larger systems (>64 processors) use this type of cache coherence.

Snooping

 * First introduced in 1983, snooping is a process where the individual caches monitor address lines for accesses to memory locations that they have cached. The write-invalidate protocols and write-update protocols make use of this mechanism.

 * For the snooping mechanism, a snoop filter reduces the snooping traffic by maintaining a plurality of entries, each representing a cache line that may be owned by one or more nodes. When replacement of one of the entries is required, the snoop filter selects for the replacement of the entry representing the cache line or lines owned by the fewest nodes, as determined from a presence vector in each of the entries. A temporal or other type of algorithm is used to refine the selection if more than one cache line is owned by the fewest nodes.

Directory-based

 * In a directory-based system, the data being shared is placed in a common directory that maintains the coherence between caches. The directory acts as a filter through which the processor must ask permission to load an entry from the primary memory to its cache. When an entry is changed, the directory either updates or invalidates the other caches with that entry.

Distributed shared memory systems mimic these mechanisms in an attempt to maintain consistency between blocks of memory in loosely coupled systems.

Coherence protocols
Coherence protocols apply cache coherence in multiprocessor systems. The intention is that two clients must never see different values for the same shared data.

The protocol must implement the basic requirements for coherence. It can be tailor-made for the target system or application.

Protocols can also be classified as snoopy or directory-based. Typically, early systems used directory-based protocols where a directory would keep a track of the data being shared and the sharers. In snoopy protocols, the transaction requests (to read, write, or upgrade) are sent out to all processors. All processors snoop the request and respond appropriately.

Write propagation in snoopy protocols can be implemented by either of the following methods: If the protocol design states that whenever any copy of the shared data is changed, all the other copies must be "updated" to reflect the change, then it is a write-update protocol. If the design states that a write to a cached copy by any processor requires other processors to discard or invalidate their cached copies, then it is a write-invalidate protocol.
 * Write-invalidate: When a write operation is observed to a location that a cache has a copy of, the cache controller invalidates its own copy of the snooped memory location, which forces a read from main memory of the new value on its next access.
 * Write-update: When a write operation is observed to a location that a cache has a copy of, the cache controller updates its own copy of the snooped memory location with the new data.

However, scalability is one shortcoming of broadcast protocols.

Various models and protocols have been devised for maintaining coherence, such as MSI, MESI (aka Illinois), MOSI, MOESI, MERSI, MESIF, write-once, Synapse, Berkeley, Firefly and Dragon protocol. In 2011, ARM Ltd proposed the AMBA 4 ACE for handling coherency in SoCs. The AMBA CHI (Coherent Hub Interface) specification from ARM Ltd, which belongs to AMBA5 group of specifications defines the interfaces for the connection of fully coherent processors.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Cache coherence


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Convair F-106 Delta Dart

The Convair F-106 Delta Dart was an all-weather interceptor aircraft designed and produced by the American aircraft manufacturer Convair.

The F-106 was designed in response to the 1954 interceptor program. Envisioned as an imagined "Ultimate Interceptor", it was a development of the F-102 Delta Dagger, and commenced as the F-102B prior to being redesignated by the United States Air Force (USAF). The F-106 was designed without a gun or provision for carrying bombs, instead carrying its AIM-4 Falcon air-to-air missiles within an internal weapons bay, its clean exterior was beneficial to supersonic flight. Major differences from the F-102 included the adoption of the more powerful Pratt & Whitney J75 turbojet engine, heavily redesigned air inlets along with a variable-geometry inlet duct to suit a wide range of supersonic speeds, application of the area rule to the fuselage shaping, and a general increase in size. On 26 December 1956, the first prototype performed its maiden flight. After flight testing demonstrated lesser performance gains than anticipated, the USAF ultimately only ordered 350 of the planned 1,000 F-106s.

Becoming operational in June 1959, the F-106 was the primary all-weather interceptor aircraft of the USAF through much of the Cold War era; it ended up being the final specialist interceptor to be used by the service to date. It was never used in combat nor were any export opportunities secured. During the 1960s, a competitive evaluation between the F-106 and the McDonnell Douglas F-4 Phantom II determined the latter to be marginally superior, yet the type continued to be operated for a further two decades due to extensive demand for the F-4 in other roles. Convair proposed various improved models of the F-106, typically focused on the radar, communications, and other avionics, but none of these schemes were pursued. In one high-profile incident over Montana on 2 February 1970, an unmanned F-106 recovered from a flat spin after its pilot had ejected, belly landing relatively intact in a snow-covered cornfield; it was recovered and continued to be flown for numerous years afterwards.

The F-106 was gradually withdrawn from USAF service during the 1980s as the arrival of newer air superiority fighters, particularly the McDonnell Douglas F-15 Eagle, had made the role of dedicated interceptors obsolete. Numerous F-106s would be operated for a time by the Air National Guard. Many withdrawn aircraft were promptly converted into target drones and redesignated QF-106 under the Pacer Six program, which were used up in 1998. A handful of F-106s were operated by NASA for experimental purposes, such as the Eclipse Project, through to 1998.

Background
The F-106 was the ultimate development of the USAF's 1954 interceptor program of the early 1950s. The initial winner of this competition had been the F-102 Delta Dagger, but early versions of this aircraft had demonstrated extremely poor performance, being limited to flying at subsonic speeds and relatively low altitudes. During the testing program the F-102 underwent numerous changes to improve its performance, notably the application of the area rule to the fuselage shaping and a change of engine, and the dropping of the advanced MX-1179 fire control system and its replacement with a slightly upgraded version of the MX-1 already in use on subsonic designs. The resulting aircraft became the F-102A, and in spite of being considered barely suitable for its mission, the Air Force sent out a production contract in March 1954, under which the first deliveries were expected during the following year.

By December 1951, the Air Force had already turned its attention to a further improved version, which was initially referred to as the F-102B. The main planned change was the replacement of the F-102A's Pratt & Whitney J57 (which had itself replaced the original J40 ) with the more powerful Wright J67 (a Bristol Olympus produced under license). By the time this engine would be available, the MX-1179 was expected to be available, and thus it was selected as well. The intended result would be the "ultimate interceptor" that the USAF had originally sought. However, while initial work on the Olympus design appeared to go well, by August 1953 Wright was already a full year behind schedule in development. Continued development did not resolve problems with the engine, and in early 1955 the Air Force approved the switch to the Pratt & Whitney J75.

The J75 was somewhat larger than the J57 in the F-102A, and had greater This demanded changes to the inlets to allow more airflow, and led to the further refinement of using a somewhat shorter variable-geometry inlet duct to allow the intakes to be tuned to best performance across a wide range of supersonic speeds. The fuselage grew slightly longer, and was cleaned up and simplified in many ways. The wing was slightly enlarged in area, and a redesigned vertical tail surface was used. The engine's two-position afterburner exhaust nozzle was also used for idle thrust control, held open to decrease thrust by 40%, resulting in slower taxiing and less brake wear.

Competing efforts and production arrangements
Throughout its early development, the F-102B had to compete for attention and resources with the F-102A; the aviation author Marcelle Knaack observed that there were fewer funds to develop the more capable systems of the F-102B, which would have been useful in more quickly overcoming some of the technical difficulties that arose. The number of F-102As on order grew substantially beyond that which been originally forecast, indicative of the growing importance attached to what had once been intended to be an interim or 'stop-gap' aircraft to fill in until the F-102B could be delivered. During December 1955, a mock-up with the expected layout of the MX-1179, now known as the MA-1, was inspected and approved.

On 18 April 1956, an extended production contract for 17 F-102Bs was issued to Convair, representing substantially fewer aircraft than had been originally anticipated at this stage. On 17 June of that year, the aircraft was officially re-designated as the F-106A. On 18 August 1956, the USAF issued a systems development directive that called for development and production of the F-106 Knaack attributed this policy as being responsible for several later problems in the program. During April 1957, the USAF formally rejected Convair's F-102C proposal (essentially a reengined model of the F-102) to concentrate on the more advanced F-106 program, which it had then anticipated to enter service during the following year.

Flight testing
On 26 December 1956, the first prototype F-106, an aerodynamic test bed, performed its maiden flight from Edwards Air Force Base. On 26 February 1957, the second prototype, which was outfitted with a fuller set of equipment, made its first flight. Early flight testing around the end of 1956 and beginning of 1957 demonstrated somewhat disappointing results, having achieved less of a performance gain over the F-102 than had been anticipated. Specifically, both the acceleration and maximum speed were beneath Convair's own estimates. Furthermore, both the engine and avionics proved to be somewhat unreliable. These combined problems, and the delays associated with them, were nearly responsible for the termination of the program.

However, the service decided to persist with the F-106 program after the Air Defense Command had heavily advocated for it. Based upon the test data submitted, USAF officials had determined that modifications to the inlet duct cowling and charging ejectors were likely to increase both acceleration and speed; modifications would be made following the completion of Category II testing and were evaluated during Category III testing. At this stage, the service enacted several measures to hasten development towards production; in April 1957, it authorized the conditional acceptance of several F-106s being used by Convair for flight testing; it also took several quick decisions to settle outstanding development questions. By mid-1957, funding for 120 F-106As had been allocated. The USAF ultimately opted to order 350 F-106s, substantially fewer than the planned fleet of 1,000 aircraft. Deliveries of the single-seat F-106A and the twin-seat F-106B combat-capable trainer variant commenced to 15 fighter interceptor squadrons in October 1959.

World Speed record

On 15 December 1959, Major Joseph W. Rogers set a world speed record of 1,525.96 mph (2,455.79 km/h) in a Delta Dart at 40,500 ft (12,300 m). That year, Charles E. Myers flew the same model aircraft at 1,544 mph (2,484 km/h).

Design
The F-106 was envisaged as a specialized all-weather missile-armed interceptor to shoot down bombers. It was complemented by other Century Series fighters for other roles such as daylight air superiority or fighter-bombing. To support its role, the F-106 was equipped with the Hughes MA-1 integrated fire-control system, which could be linked to the Semi-Automatic Ground Environment (SAGE) network for ground control interception (GCI) missions, allowing the aircraft to be steered by controllers. The MA-1 proved extremely troublesome and was eventually upgraded more than 60 times in service.

Similarly to the F-102, the F-106 was designed without a gun, or provision for carrying bombs, but it carried its missiles in an internal weapons bay for clean supersonic flight. It was armed with four Hughes AIM-4 Falcon air-to-air missiles (either AIM-4G infra-red guided missiles or semi-active radar homing (SARH)-guided (which detected reflected radar signals) AIM-4E/F missiles ), along with a single 1.5 kiloton-warhead AIR-2 (MB-2) Genie unguided air-to-air rocket intended to be fired into enemy bomber formations. Like its predecessor, the F-102 Delta Dagger, it could carry a drop tank under each wing. Later fighters such as the McDonnell Douglas F-4 Phantom II and McDonnell Douglas F-15 Eagle carried missiles recessed in the fuselage or externally, but stealth aircraft would re-adopt the idea of carrying missiles or bombs internally for reduced radar signature.

The first ejection seat fitted to early F-106s was a variation of the seat used by the F-102 and was called the Weber interim seat. It was a catapult seat which used an explosive charge to propel it clear of the aircraft. This seat was not a zero-zero seat and was inadequate for ejections at supersonic speeds as well as ground level ejections and ejections at speeds below 120 kn and 2,000 ft. The second seat that replaced the Weber interim seat was the Convair/ICESC (Industry Crew Escape System Committee) Supersonic Rotational B-seat, called the supersonic "bobsled", hence the B designation. It was designed with supersonic ejection as the primary criterion since the F-106 was capable of Mach-2 performance. Fighter pilots viewed high speed ejections as the most important. Seat designers viewed an ejection at low altitude and slow speed as the most likely possibility. The ejection sequence with the B-seat was quite complicated and there were some unsuccessful ejections that resulted in pilot fatalities. The third seat, that replaced the Convair B-seat, was the Weber Zero-Zero ROCAT (for Rocket Catapult) seat. Weber Aircraft Corporation designed a "zero-zero" seat to operate at up to 600 kn. High-altitude supersonic ejections were rare and ejections at relatively low altitudes and low speeds were more likely. The Weber "zero-zero" seat was satisfactory and was retrofitted to the F-106 after 1965.

Operational history

Early operations of the F-106 were troubled by numerous technical issues. These included generator defects, fuel-flow issues (particularly during cold weather), and combustor-starter malfunctions. During December 1959, all F-106s were temporarily grounded following the accidental jettisoning of the canopy mid-flight on one aircraft. Many, but not all, of these problems were resolved by the start of 1961; this can be partially attributed to two major modification and retrofit program conducted during this timeframe. Following the resolution of initial teething problems – in particular an ejection seat that killed the first 12 pilots to eject from the aircraft – its exceptional performance led to the aircraft becoming relatively popular amongst its pilots.

The F-106 served in the contiguous US, Alaska, and Iceland, as well as for brief periods in Germany and South Korea. The F-106 was the second highest sequentially numbered P/F- aircraft to enter service under the old number sequence (the F-111 was highest), before the system was reset under the 1962 United States Tri-Service aircraft designation system. In service, the F-106's official name, "Delta Dart," was rarely used, and the aircraft was universally known simply as "The Six." The arrival of the F-106 in quantity quickly led to the withdrawal of various older aircraft that were being used in the interceptor role, such as the North American F-86 Sabre and the Northrop F-89 Scorpion.

Although contemplated for use in the Vietnam War, the F-106 never saw combat, nor was it exported to foreign users. After the cancellation of their own Avro Arrow, the Canadian government briefly considered purchasing the F-106C/D.

To standardize aircraft types, the USAF was directed to conduct Operation Highspeed, a flyoff competition between the USAF F-106A and the U.S. Navy F4H-1 (F-4B) Phantom, which was not only as capable as the F-106 as a missile-armed interceptor but could carry as large a bomb load as the Republic F-105 Thunderchief fighter-bomber. The Phantom was the winner but would first be used to escort and later replace the F-105 fighter-bomber in the late 1960s before replacing older interceptors in Air Defense Command in the 1970s.

The F-106 was progressively updated in service, with improved avionics, a modified wing featuring a noticeable conical camber, an infrared search and track system, streamlined supersonic wing tanks which provided virtually no degradation to overall aircraft performance, better instrumentation and features like an inflight refuelling receptacle and an arrestor hook for landing emergencies.

Air-to-air combat testing suggested "The Six" was a reasonable match for the F-4 Phantom II in a dogfight, with superior high-altitude turn performance and overall maneuverability (aided by the aircraft's lower wing loading). The Phantom had better radar – operated by an additional crewman – and could carry a load of up to four radar-guided AIM-7 Sparrow and four infrared AIM-9 Sidewinder missiles, while the AIM-4 Falcon missiles carried by the F-106 proved a disappointment for dogfighting over Vietnam. The F-4 had a higher thrust/weight ratio with superior climb, better high speed/low-altitude maneuverability and could be used as a fighter-bomber. Air combat experience over Vietnam showed the need for increased pilot visibility and the utility of a built-in gun, which had been added to the "E" variant of USAF Phantoms.

In 1972, some F-106As were upgraded in Project Six Shooter that involved fitting the F-106 with a new canopy without metal bracing which greatly improved pilot visibility. Also added was an optical gunsight and provision for a M61 Vulcan 20 mm cannon. The M61 Vulcan had 650 rounds of ammunition in the center of the weapons bay, being used in place of the AIR-2 Genie. Many F-106 units opted to fly without the gun, retaining their nuclear payload instead. The F-15A Eagle started replacing the F-106 in 1981, with "The Sixes" typically passed on to Air National Guard units. The F-106 remained in service in various USAF and ANG units until 1988.

Retirement and conversion into drones
Between 1 June 1983 and 1 August 1988 the Delta Darts were incrementally retired and sent to the Military Storage and Disposition Center in Arizona. When the need for a high performance Full Scaled Aerial Target Drone was required, the USAF began withdrawing Delta Darts from storage. Starting in 1986, 194 of the surviving surplus aircraft were converted into target drones and these were designated QF-106As and used for target practice vehicles under the Pacer Six Program by the Aerial Targets Squadron. The last was destroyed in January 1998. The drones were still capable of being flown as manned aircraft, such as for ferrying to a test; during the test they were flown unmanned. The QF-106 replaced the QF-100 Super Sabre drone; the last shoot down of a QF-106 (57-2524) took place at Holloman AFB on 20 February 1997 after which the QF-106 was superseded by the QF-4S and QF-4E Phantom II drone.

NASA research and test aircraft
Six F-106s were retained by NASA for test purposes through 1998. An F-106B two-seat trainer was operated by NASA Langley Research Center between 1979 and 1991. This Delta Dart was used in research programs ranging from testing supersonic engines to improving maneuverability of fighters. Between 1980 and 1986 the aircraft was modified for the purpose of lightning strike research and became known as the Lightning Strike Plane and was struck 714 times without damage. On one hour-long flight at 38,000 ft in 1984, lightning struck the research aircraft 72 times. One significant modification was the replacement of the composite nose radome by a metallic radome. Although the maximum speed of the F-106 was Mach 2.3, during the lightning experiments it was flown at subsonic speeds into clouds at 300 kn from 5,000 to 40,000 ft. The aircraft was equipped with optical sensors which consisted of a video camera and a light detector. Data acquisition was performed with 1980s state of the art digital waveform recorders.

Eclipse project
NASA used six drones in its Eclipse Project which ran from 1997 to 1998. The Dryden Flight Research Center supported project Eclipse which sought to demonstrate the feasibility of a reusable Aerotow-launch vehicle. The objective was to tow, inflight, a modified QF-106 aircraft with a C-141A transport aircraft. The test demonstrated the possibility of towing and launching a space launch vehicle from behind a tow plane.

The Cornfield Bomber

On 2 February 1970, an F-106 of the 71st Fighter-Interceptor Squadron, piloted by Captain Gary Foust, entered a flat spin over Montana. Foust followed procedures and ejected from the aircraft. The resulting change of balance caused the aircraft to stabilize and later belly land in a snow-covered field, suffering only minor damage. The aircraft, promptly nicknamed "The Cornfield Bomber", was then sent back to base by rail, repaired and returned to service, and is now on display at the National Museum of the United States Air Force.

Variants

 * F-102B: The original designation of the F-106A.
 * F-106A: (Convair Model 8-24) Improved version of the F-102. Fitted with the MA-1 Integrated Fire Control System with SAGE datalink, J-75 afterburning turbojet, enlarged intake, variable-geometry inlet ramps and shortened intake ducts, refined fuselage shape, modified wings and redesigned tailfin; tailpipe fitted with a device to reduce the tendency of the jet exhaust to blow unsecured objects around while taxiing, yet allowing virtually maximum performance at high thrust settings including afterburner. Performance was deemed unsatisfactory and modifications were made. The aircraft was capable of low supersonic speeds without afterburner (but with a significant range penalty) and had a maximum altitude at least 57,000 ft. Many were fitted with a conically cambered wing for improved takeoff, supersonic and high-altitude flight. To improve the aircraft's range the aircraft was fitted with two streamlined external supersonic tanks that still kept the aircraft capable of sustained roll rates of 100 degrees per second. Since these tanks produced virtually no significant performance degradation they were rarely jettisoned and were routinely carried around. After 1972, many F-106s were refitted with a new canopy featuring improved visibility, improved optic sights and provision for a gunpack in the center weapons bay.
 * F-106B Delta Dart.jpgF-106B: (Convair Model 8-27) Two-seat, combat-capable training version. Pilot and instructor are seated in tandem. Due to the extra seat, the fuselage is actually better area ruled; combined with a likely reduction in weight. Weapons configurations same as F-106A.
 * NF-106B: This designation was given to two F-106Bs used as test aircraft with NASA and associated research facilities from 1966 to 1991.
 * F-106C: Unbuilt version. Aircraft was intended to have the AN/ASG-18 radar and fire control system fitted originally developed for the North American XF-108 Rapier. For its time, it was the largest radar to ever be fitted to a fighter, actually requiring hydraulic actuators to turn the antenna. To accommodate this larger radar system, the nose cone was longer and of greater diameter. The design featured an improved raised canopy design featuring better visibility, canards and lengthened rectangular inlet ducts. The aircraft was to be capable of carrying one GAR-9/AIM-47A in its center bay and one AIM-26A in each side bay. At one time, the US Air Force had considered acquiring 350 of these advanced interceptors, but the F-106C/D project was cancelled on 23 September 1958.
 * F-106D: Unbuilt two-seat version of the F-106C.
 * F-106X: Unbuilt version (early 1968). It would have been outfitted with canards and powered by a JT4B-22 turbojet. It was envisioned as an alternative to the Lockheed YF-12, and was to have had a fire control system with "look-down/shoot-down" capability fed by a 40 inch radar dish.
 * F-106E: Unbuilt version. On 3 September 1968, Convair issued a proposal for an "improved" interceptor that was to be designated F-106E/F. It was to be compatible with the upcoming airborne warning and control systems as well as with the "over-the-horizon" radar defense network. The F-106E/F would have had a longer nose and a new and improved radar with a look-down/shoot-down tracking and missile launch capability. It would also have had a two-way UHF voice and datalink radio. It would have been capable of launching both nuclear and non-nuclear missiles, including the AIM-26 Nuclear Falcon and the AIM-47.
 * F-106F: Unbuilt two-seat version of the F-106E.
 * QF-106A: Converted into drones, were still capable of being flown both as manned and unmanned aircraft.
 * F-106 RASCAL Project: Unbuilt version. It would have been a low cost satellite launcher.

Operators

 * United States Air Force
 * United States Air Force

 * Air Defense Command / Aerospace Defense Command / Tactical Air Command
 * 2nd Fighter-Interceptor Squadron – Wurtsmith AFB (1971–1972)
 * 5th Fighter-Interceptor Squadron – Minot AFB (1960–1985)
 * 11th Fighter-Interceptor Squadron – Duluth AFB (1960–1968)
 * 27th Fighter-Interceptor Squadron – Loring AFB (1959–1971)
 * 48th Fighter-Interceptor Squadron – Langley AFB (1960–1982)
 * 49th Fighter-Interceptor Squadron – Griffiss AFB (1968–1987)
 * 71st Fighter-Interceptor Squadron – Richards-Gebaur AFB (1960–1971)
 * 83rd Fighter-Interceptor Squadron – Loring AFB (1971–1972)
 * 84th Fighter-Interceptor Squadron – Hamilton AFB (1968–1973); Castle AFB (1973–1981)
 * 87th Fighter-Interceptor Squadron – Duluth AFB (1968–1971); K.I. Sawyer AFB (1971–1985)

 * 94th Fighter-Interceptor Squadron – Selfridge AFB (1960–1971)
 * 95th Fighter-Interceptor Squadron – Andrews AFB (1959–1973)
 * 318th Fighter Interceptor Squadron – McChord AFB (1960–1983)
 * 319th Fighter-Interceptor Squadron – Bunker Hill AFB (1960–1963) / Grissom AFB (1971–1972)
 * 329th Fighter-Interceptor Squadron – George AFB (1960–1967)
 * 437th Fighter-Interceptor Squadron – Oxnard AFB (1968–1968)
 * 438th Fighter-Interceptor Squadron – Kincheloe AFB (1960–1968)
 * 456th Fighter-Interceptor Squadron – Castle AFB (1959–1968)
 * 460th Fighter-Interceptor Squadron – Oxnard AFB (1968–1974)
 * 498th Fighter-Interceptor Squadron – Geiger Field (1959–1968)
 * 539th Fighter-Interceptor Squadron – McGuire AFB (1959–1967)

 * Air National Guard
 * 101st Fighter Interceptor Squadron, MA ANG – Otis ANGB (1972–1988)
 * 119th Fighter Interceptor Squadron, NJ ANG – Atlantic City ANGB (1972–1988)
 * 159th Fighter Interceptor Squadron, FL ANG – Jacksonville ANGB (1974–1987)
 * 171st Fighter Interceptor Squadron, MI ANG – Selfridge ANGB (1972–1978)
 * 186th Fighter Interceptor Squadron, MT ANG – Great Falls ANGB (1972–1987)
 * 194th Fighter Interceptor Squadron, CA ANG – Fresno ANGB (1974–1984)

 * NASA

Aircraft on display

 * F-106A
 * 56-0451 – Selfridge Military Air Museum, Selfridge Air National Guard Base, Michigan.
 * 56-0454 – Holloman AFB, New Mexico.
 * 56-0459 – McChord Air Museum, McChord AFB, Washington.
 * 56-0460 – Minot AFB, North Dakota.
 * 56-0461 – K. I. Sawyer AFB Heritage Air Museum at the former K. I. Sawyer AFB / now Sawyer International Airport, Marquette, Michigan.
 * 57-0230 – 125th Fighter Wing, Jacksonville Air National Guard Base at Jacksonville International Airport, Florida.
 * 58-0774 – Hill Aerospace Museum, Hill AFB, Utah.
 * 58-0787 – National Museum of the United States Air Force, Wright-Patterson AFB, Dayton, Ohio. Nicknamed the "Cornfield Bomber", this F-106 landed itself with relatively minor damage in a farmer's field after its pilot lost control and ejected. It last served with the 49th Fighter Squadron before being brought to the museum in August 1986.
 * 58-0793 – Castle Air Museum at the former Castle AFB, Atwater, California.
 * 59-0003 – Pima Air & Space Museum, adjacent to Davis-Monthan AFB in Tucson, Arizona.
 * 59-0010 – Aerospace Museum of California, McClellan Airfield (former McClellan AFB), Sacramento, California.
 * 59-0023 – Air Mobility Command Museum, Dover AFB, Delaware.
 * 59-0043 – 309th Aerospace Maintenance and Regeneration Group, Davis-Monthan AFB, Arizona.
 * 59-0069 – Great Falls Air National Guard Base, Great Falls Airport, Montana.
 * 59-0086 – Pacific Coast Air Museum, Santa Rosa, California.
 * 59-0105 – Camp Blanding Museum, Camp Blanding Florida National Guard Joint Training Center, Middleburg, Florida.
 * 59-0123 – Museum of Aviation, Robins AFB, Warner Robins, Georgia.
 * 59-0134 – Peterson Air and Space Museum, Peterson AFB, Colorado Springs, Colorado.
 * 59-0137 – Evergreen Aviation & Space Museum, McMinnville, Oregon.
 * 59-0145 – Tyndall Air Park, Tyndall AFB, Florida.
 * 59-0146 – 144th Fighter Wing, Fresno Air National Guard Base, Fresno, California.

 * F-106B
 * 57-2509 – Palm Springs Air Museum, Palm Springs, California.
 * 57-2513 – Yanks Air Museum, Chino, California.
 * 57-2523 – Atlantic City Air National Guard Base, Atlantic City, New Jersey.
 * 57-2533 – Kelly Field Heritage Museum, Lackland AFB/Kelly Field (former Kelly AFB), Texas.
 * 59-0158 – Edwards AFB Century Circle, Edwards AFB, California.

 * NF-106B
 * 57-2516 – Virginia Air and Space Center / Hampton History Center, Hampton, Virginia.

title: Convair F-106 Delta Dart


text:
Talk:Songkran (Thailand)

Who know starting which year Songkran was fixed to April 13
Who know starting which year Songkran was fixed to April 13? Accoring to Holidayfestival in 1997 it was on April 14-16 instead - can anyone disprove this? Ahoerstemeier 21:17 Jan 30, 2003 (UTC)

The name songkran appears to be a corruption of Sankranthi...is it?

I have more photos on my web site (including higher resolution versions of the two on this page). I don't want to add a link to my site to the main page. If anybody else feels it's worth it then put it on there: http://www.kirit.com/สงกรานต์—Songkran. I can upload any other pictures to Commons if anybody wants to use them in the article. KayEss | talk 05:18, 14 August 2006 (UTC)

 * A picture of the traditional ceremony would be nice. I see there is one on your site, but it's not clear to me what's happening in it. HenryFlower 19:12, 15 August 2006 (UTC)

 * I was trying to get some better pictures of that, but they didn't come out well enough. It'll have to wait until next year now KayEss | talk 04:20, 21 August 2006 (UTC)

Move to Songkran or Songkran Festival?
The celebrations are commonly known as such in English, especially in tourism, and the new year aspect of the festivals is somewhat diminished nowadays. Paul C 21:29, 16 August 2006 (UTC)

 * The first day of the Khmer New Year is also called Songkran, which may be a problem. Of course if we were really being fair then Songkran wouldn't redirect here. So I'm neutral. HenryFlower 23:11, 16 August 2006 (UTC)

 * I think we should. User:Ethanfeng308.10719User talk:Ethanfeng308.10719 13:53, 21 March 2021 (UTC)

Sawatdi pi mai
I really doubt that sawatdi pi mai is really traditional new year greeting. The word sawatdi, from sanskrit svasti, as a greeting began only in mid-20th century, during the regime of Plaek Phibunsongkhram. -- KINKKU  •  ANANAS  16:45, 4 March 2008 (UTC)

Annually for 70 years, has a ring of tradition to it. TheHamburger (talk) 06:51, 4 December 2017 (UTC)

fix subhead and photo?
I don't know how to move the subhead "Greetings" or the photo so that they do not overlap. — Preceding unsigned comment added by Ed8r (talk • contribs) 17:33, 25 February 2011 (UTC)

Google Chedi Sai Songkran
2011 April 15, I accessed Google from Thailand, which automatically sends me to the Thai version. I requested the standard English version, and got a start page with GOOGLE rendered in Indic script. Clicking on the image returned ก่อเจดีย์ทรายวันสงกรานต์ search for sand chedi songkran. Chedi is the usual Thai term for stupa, and เจดีย์ทราย chedi sai is a Buddhist form of sand art and play. I don't know that users outside Thailand get the same image (and search result) so won't post it to the article. The 'sand play and art' involves bringing river sand to a wat at the end of the Dry Season, to renew sand carried away on feet during the year, lest the wat become a hole in the ground. The sand is formed into Buddhist motifs, which are then washed away by the coming rains, giving a lesson on the impermanence of life.

Except for the Sand Chedi, Ban Plab T.Duthung +15° 53' 29.26" +104° 4' 55.29" A.Meuang Yasothon, that the local people say is over 400 years old. It is near, but not on, the grounds of the village wat. Its lesson is the persistence of the local people, despite everything modern trying to wash them away. Since it is not appropriate for Wikipedia, I suppose I should write it up for Wikitravel. But GOOGLE's 15 April start page, at least when accessed from Thailand, beat me to it. --Pawyilee (talk) 15:37, 13 April 2011 (UTC) --Pawyilee (talk) 13:20, 14 April 2011 (UTC)

Public nudity
...fined THB500 each... I strongly suspect that the abbreviation "THB" is not commonly understood by speakers of English; I recommend spelling-out "Thai baht." A rough conversion to a more familiar currency like "around $15" or "around £10" or even "around 14½€" might also be helpful. ☺ Dick Kimball (talk) 12:26, 13 April 2015 (UTC)

THB is commonly used as the abbreviation for Thai Baht much like USD, GBP or Eur. It is the ISO 4217 standard. The symbol is ฿, which has subsequently appropriated by the Bitcoin community. I don't think a rough conversion is necessary. The THB is not pegged to any other currency. TheHamburger (talk) 06:44, 4 December 2017 (UTC)

Not a lunar New Year
Why does the link to other articles at the top of this one imply that Songkran is a "lunar" new year?

"For other traditions of celebrating the lunar new year, see Lunar New Year." implies that it's lunar or at least lunisolar, but the description of the calculation of the date doesn't involve the moon at all, it involves the sun entering a specific place in the zodiac, making this a solar calendar. — Preceding unsigned comment added by 71.114.46.209 (talk) 01:13, 10 February 2021 (UTC)

Meme

 * SuS*

😗 103.165.115.77 (talk) 15:30, 26 March 2022 (UTC)

Citation issues
Some of the citations like 3 and 6 return document not found or just put you on the home page of the website, is there any archive of these or is it a lost cause? Bean guy2 (talk) 08:29, 22 February 2024 (UTC)

 * The citations are well-formatted references to print sources, so they remain valid as offline sources. Anyway, I've replaced the Thai Royal Institute link. --Paul_012 (talk) 09:53, 22 February 2024 (UTC)

Origin of the world "Songkran"
I found out that Wiki Songkran said "The word Songkran is a  Thai  word". But in Wiki Songkran (Thailand) said "Songkran is a  Khmer  word". Which one is the right one? Utopiabandish (talk) 08:20, 14 April 2024 (UTC)

 * @Utopiabandish The word Songkran is  Thai  word as citations states;
 * V. S. Bhaskar, Government of Assam, India. (2009). "Festivals: Songkran", Faith & Philosophy of Buddhism. New Delhi, India: Kalpaz Publications. 312 pp. pp. 261-262. ISBN 978-817-8-35722-5 . "Songkran is a Thai word which means 'move'..."
 * Anouska Komlosy. "Procession and Water Splashing: Expressions of Locality and Nationality during Dai New Year in Xishuangbanna: Songkran", The Journal of the Royal Anthropological Institute, 10(2). (2004, June). London: Royal Anthropological Institute of Great Britain and Ireland. JSTOR #i370994. p. 357. " The term Songkran is a Thai word meaning ' to move ', and it refers here to the Sun, which moves into the sign of Aries at this time of the year."
 * Prakong Nimmanahaeminda, Academy of Arts, Royal Society of Thailand. "Myth and Ritual : A Study of the Songkran Festival", The Journal of The Royal Society of Thailand, 29(1–2), (2004, January–March). pp. 345–350. " Songkran is a Thai word which means of movement."
 * Malaysia, Jabatan Perpaduan Negara Dan Integrasi Nasional (JPNIN). (1985). Festivals and religious occasions in Malaysia. (First series). Kuala Lumpur: The National Unity Department of Malaysia, Prime Minister's Dept. 36 pp. p. 26. "‘SONGKRAN’ is a Traditional New Year of the Thai people and this day normally fulls in the month of April. 'SONGKRAN' is a Thai word meaning change of exchange ."
 * Sir. Philip John Newling Ward, Maj. Gen. (1974). "THE SONGKRAN FESTIVAL", Bangkok: Portrait of a City. Cambridge, United Kingdom: The Oleander Press. 136 pp. p. 111. ISBN 978-090-2-67544-5 . " Thai word ' Songkran ' literally means a move or chang e".
 * James Hastings, John Alexander Selbie, Louis Herbert Gray. (1912). "FESTIVALS AND FACTS (Siamese)", Encyclopaedia of Religion and Ethics Vol. 5. New York: Charles Scribner's Sons. p. 886.
 * I also did research many books, no information of "Songkran is a Khmer word". Thanks Quantplinus (talk) 03:43, 15 April 2024 (UTC)

Arrest section importance?
Does the current section warrant keeping on the page under "Controversies"?

For starters, the link for the second arrest is dead.

The first one mentions a 300 baht fine, which is tiny, even for Thai wages. That's basically under an hour's minimum wage for a local, and equivalent to $1 USD for a foreigner. I'm not sure it rises to the level of the "controversy" section it's under. SashaBerkman (talk) 14:32, 15 April 2024 (UTC)

title: Talk:Songkran (Thailand)


text:
Talk:Infinite monkey theorem

Monkey caption
Previously, the caption said "A Chimpanzee probably not writing Hamlet." This was funny, but perhaps too humorous for an article. A user opted to change it to "a chimpanzee sitting at a typewriter," which, although changing the caption is reasonable, strikes me as redundant. Worth changing to something else? Delukiel (talk) 13:09, 21 October 2023 (UTC)

 * I changed it to "A chimpanzee typing random characters", which seems to capture both the sense of the image and the article. — Loadmaster (talk) 16:39, 22 October 2023 (UTC)
 * Works for me! Delukiel (talk) 00:35, 24 October 2023 (UTC)
 * This was discussed (briefly) in talk:Infinite monkey theorem/Archive 4. I still think it's fine to have it.  It's a little bit The Economist-style, but I don't think it outrages the encyclopedic form. --Trovatore (talk) 00:51, 24 October 2023 (UTC)
 * Either one works for me (admittedly, I prefer the original, but I love goofball captions), I just thought what it was changed to was redundant. Delukiel (talk) 01:12, 24 October 2023 (UTC)
 * +1 for the original, it really doesn't hurt anyone. Dialmayo (talk) (Contribs) she/her 11:21, 24 October 2023 (UTC)
 * I've changed it back to the original. Delukiel (talk) 06:34, 26 October 2023 (UTC)
 * :D Dialmayo (talk) (Contribs) she/her 19:47, 26 October 2023 (UTC)
 * Now changed to "A chimpanzee writing Hamlet"! Didlidoo (talk) 01:05, 29 May 2024 (UTC)
 * too far, man Dialmayo 01:53, 29 May 2024 (UTC)
 * Can it stay, or do we need to get rid of it :( Didlidoo (talk) 02:07, 29 May 2024 (UTC)
 * @Didlidoo the edit was reverted 3 minutes after you made it Dialmayo 02:09, 29 May 2024 (UTC)
 * D: Didlidoo (talk) 03:27, 29 May 2024 (UTC)
 * an encyclopedia is supposed to not say stuff like that in image captions, this is only for non serious wikis like rationalwiki (wikipedia also is not serious but at least somewhat serious/trustworthy compared to rationalwiki) 2A02:3100:3A3F:7B00:55C0:7B8F:9CAD:F16C (talk) 03:54, 20 July 2024 (UTC)

Use of $$ = \infty $$ versus $$ \rightarrow \infty $$
The math expression shown under "Infinite strings" section is a divergent series, but currently it is written as $$= \infty $$. I think this is incorrect because series do not equal infinity. It could be changed to $$\rightarrow \infty $$ or perhaps just remove the $$= \infty $$, since its divergence is already stated. Jordanmrfox (talk) 20:48, 1 February 2024 (UTC)
 * Well, that depends on how you formulate the notion of infinite sum. The statement as written is correct, if you use the appropriate definition.  That said, of course in this particular case it doesn't matter much, because a probability can't be greater than 1, so it's already a contradiction once you get that far. --Trovatore (talk) 23:28, 1 February 2024 (UTC)
 * Thanks for your response. I looked at the wikipedia articles for Series (mathematics), Convergent series, Divergent series, Infinite expression, and I do not see a use of $$ = \infty $$ anywhere.
 * The page Convergent series uses the arrow notation in expressions like
 * $${1 \over 1}+{1 \over 2}+{1 \over 3}+{1 \over 4}+{1 \over 5}+{1 \over 6}+\cdots \rightarrow \infty. $$
 * If one accepts that the $$ + \cdots $$ means exactly the same thing as summation to infinity, then I think the arrow is the best choice.
 * However, Borel–Cantelli lemma, which this page cites, uses the $$ = \infty $$ notation a number of times.
 * Perhaps this is just a stylistic difference between pure math and statistics. I don't think anyone will be seriously confused about what $$ = \infty $$ means, but pedagogically I think we should try to all use the same standard. Jordanmrfox (talk) 21:11, 25 February 2024 (UTC)
 * I would actually be in favor of changing to "= ∞" in the "convergent series" page -- it looks weird to have a fixed expression, even containing an ellipsis, that uses the arrow notation. The thing that approaches infinity is the sequence of finite sums, but the left-hand side is an infinite sum, not a sequence of finite sums. --Trovatore (talk) 20:06, 24 May 2024 (UTC)
 * You could simply argue that the sum of a divergent infinite series does not just approach infinity, but is equal to infinity (∞), since the sum exceeds any finite number. — Loadmaster (talk) 22:49, 12 July 2024 (UTC)

title: Talk:Infinite monkey theorem


text:
Appliance

Appliance may refer to:

Electrical equipment and machinery

 * Computer appliance, a computing device with a specific function and limited configuration ability, e.g.:
 * Storage appliance, provides storage functionality for multiple attached systems using the transparent local storage area networks paradigm
 * Anti-spam appliances, detect and eliminate e-mail spam
 * Firewall (computing), a computer appliance designed to protect computer networks from unwanted traffic
 * Network appliance, a general purpose router (computing)
 * Security appliance, a computer appliance designed to protect computer networks from unwanted traffic
 * Software appliance, a software application that might be combined with just enough operating system (JeOS) for it to run optimally on industry standard hardware
 * Virtual appliance, a pre-configured virtual machine image, ready to run on a hypervisor
 * Home appliance, a household machine that uses electricity or some other energy input which includes MVHR units
 * Small appliance, also called a small domestic appliance or small electric, a portable or semi-portable machine, generally used on a table top, counter top, or other platform, to accomplish a household task
 * Major appliance, or domestic appliance, a large machine used for routine a housekeeping task

Arts, entertainment, and media

 * Appliance (band), a British musical group
 * Appliance, a motion pictures industry term for a latex piece, such as false ears or other features, used by make-up artists

Fire safety

 * Fire alarm notification appliance, an active fire protection component of a fire alarm system
 * Fire apparatus, a fire engine or fire truck in British English

Healthcare

 * Appliance, in medicine and dentistry, a device custom-fitted to an individual for the purpose of correction of a physical or dental problem, e.g.:
 * Dental braces
 * Orthotics, an orthotic appliance
 * Prosthesis

title: Appliance


text:
Crewe

Crewe is a railway town and civil parish in the unitary authority of Cheshire East in Cheshire, England. The civil parish of Crewe had a population of 55,318 in the 2021 census. The larger Crewe built-up area, which also covers parts of the adjacent civil parishes of Willaston, Shavington cum Gresty and Wistaston, had a total population of 76,437 in 2021.

Crewe is perhaps best known as a large railway junction and home to Crewe Works; for many years, it was a major railway engineering facility for manufacturing and overhauling locomotives, but now much reduced in size. From 1946 until 2002, it was also the home of Rolls-Royce motor car production. The Pyms Lane factory on the west of the town now exclusively produces Bentley motor cars. Crewe is 158 mi northwest of London, 28 mi south of Manchester city centre, and 31 mi southeast of Liverpool city centre.

Medieval
The name derives from an Old Welsh word criu, meaning 'weir' or 'crossing'. The earliest record is in the Domesday Book, where it is written as Creu. The original settlement of Crewe lies to the east of the modern town. It was a township in the parish of Barthomley. The original settlement of Crewe later became known as Crewe Green to distinguish it from the newer town to its west.

Modern
The town of Crewe owes its existence to Crewe railway station, which opened in 1837 on the Grand Junction Railway. When the route for the railway was being planned, alternative routes and locations for the main station in this area were considered; Winsford, 7 miles (11 km) to the north, had rejected an earlier proposal, as had local landowners in neighbouring Nantwich, 4 miles (6 km) away. The company then settled on the route through Crewe and the station was built in fields near Crewe Hall. The station was in the township of Crewe, but the land north-west of the station was in the neighbouring township of Monks Coppenhall, which formed part of the parish of Coppenhall.

The company built its main locomotive works to the north of Crewe railway station, and a "railway colony" soon started developing in the area north-west of the station. In 1840 Joseph Locke, chief engineer of the Grand Junction Railway, produced plans for a new town there. The railway company built much of the early town itself in the 1840s and 1850s. Although the nascent town was in the township of Monks Coppenhall rather than the Crewe township, it was known as Crewe from the start. The modern town of Crewe was thus named after the railway station, rather than the other way round.

In 1859 the township of Monks Coppenhall was made a local board district, giving the town its first form of local government. The district's name was changed from Monks Coppenhall to Crewe in 1869. Townships were redefined as civil parishes in 1866, and whilst the local board district was renamed in 1869 the civil parish was not. As such, there was a Crewe district which contained the parish of Monks Coppenhall, but did not contain the parish of Crewe. An old, local riddle describes the somewhat unusual states of affairs: "The place which is Crewe is not Crewe, and the place which is not Crewe is Crewe."

The population expanded rapidly to reach 40,000 by 1871. In 1877 the Crewe local board district was incorporated to become a municipal borough. The town has a large park, Queen's Park (laid out by engineer Francis Webb), the land for which was donated by the London and North Western Railway, the successor to the GJR. It has been suggested that their motivation was to prevent the rival Great Western Railway building a station on the site, but the available evidence indicates otherwise.

Webb took a great interest in local politics and was "the most influential individual in the town". "Described just before his retirement as 'the King of Crewe', Webb came to exercise control over the working lives of over 18,000 men - one third of the total LNWR workforce. Over half these lived in Crewe, around 8,000 being employed at the locomotive works. Several recreational and sporting organisations were a direct result of Webb's influence and others received benefit from his support." These included the LNWR Cricket Club (established in 1850) and the Crewe Alexandra Athletic Club (established in 1867). However, Webb's influence allegedly also extended to intimidation of Liberal Party sympathisers. In September 1885, the editor of the Crewe Chronicle published charges against Webb, saying "That through the action, direct and indirect, of Tory railway officialism, the political life of Crewe is cramped and hindered beyond recognition". In November 1889, Crewe Town Council debated a motion which accused LNWR managers of working with Crewe Tories "to crush Liberalism altogether out of the town": "... by intimidation and persecution of your Liberal workmen, and by making the chances of promotion depend upon subserviency to the Tory political demands of the Management, they have created a state of political serfdom in the works." In December 1889, Liberal statesman William Ewart Gladstone wrote a letter to the Chronicle condemning the company's behaviour in the town.

The railway provided an endowment towards the building and upkeep of Christ Church. Until 1897 its vicar, non-conformist ministers and schoolteachers received concessionary passes, the school having been established in 1842. The company provided a doctor's surgery with a scheme of health insurance. A gasworks was built and the works water supply was adapted to provide drinking water and a public baths. The railway also opened a cheese market in 1854 and a clothing factory for John Compton who provided the company uniforms, while McCorquodale of Liverpool set up a printing works.

The railway station remained part of the neighbouring parish of Crewe rather than the borough of Crewe until 1936. The borough boundary was significantly enlarged in 1936 to absorb the parish of Church Coppenhall and parts of several other neighbouring parishes, including the area of Crewe parish around the railway station. The reduced Crewe parish to the east of the town formally changed its name to Crewe Green in 1984.

During World War II the strategic presence of the railways and Rolls-Royce engineering works (turned over to producing aircraft engines) made Crewe a target for enemy air raids, and it was in the flight path to Liverpool. The borough lost 35 civilians to these, the worst raid was on 29 August 1940 when some 50 houses were destroyed, close to the station.

Crewe crater on Mars is named after the town of Crewe. Crewe was described by author Alan Garner in his novel Red Shift as "the ultimate reality".

Crewe was mentioned in 1984 as the setting of the 19th episode The Flying Kipper, in the first series of Thomas & Friends.

Governance
Crewe is within the United Kingdom Parliamentary constituency of Crewe and Nantwich. Crewe is within the ceremonial county of Cheshire.

Since April 2009 Crewe has been administered by the unitary authority, Cheshire East Council; at parish level, since 4 April 2013, local matters have been dealt with by Crewe Town Council, which is based at 1 Chantry Court, Forge Street, Crewe, CW1 2DL.

Crewe applied for City status as part of the Platinum Jubilee Civic Honours in 2022. The application was unsuccessful and Crewe remains a town.

Climate
Like most of the United Kingdom, Crewe has an oceanic climate, with warm summers and cool winters and relatively little temperature change throughout the year.

Economy
The railways still play a part in local industry at Crewe Works, which carries out train maintenance and inspection. It has been owned by Alstom since 2021. At its height, the site employed over 20,000 people, but by 2005 fewer than 1,000 remained, with a further 270 redundancies announced in November of that year. Currently Alstom employs 6000 people across the UK and Ireland. Much of the site once occupied by the works has been sold and is now occupied by a supermarket, leisure park, and a large new health centre.

There is still an electric locomotive maintenance depot to the north of the railway station, operated by DB Cargo UK. The diesel locomotive maintenance depot, having closed in 2003, reopened in 2015 as a maintenance facility for Locomotive Services Limited, having undergone major structural repairs.

The Bentley car factory is on Pyms Lane to the west of town. As of early 2010, there are about 3,500 working at the site. The factory used to produce Rolls-Royce cars, until the licence for the brand transferred from Bentley's owners Volkswagen to rival BMW in 2003.

There is a BAE Systems Land & Armaments factory in the village of Radway Green near Alsager, producing small arms ammunition for the British armed forces.

The headquarters of Focus DIY, which went into administration in 2011, was in the town. Off-licence chain Bargain Booze is also Crewe-based. It was bought-out in 2018 by Sir Anwar Pervez' conglomerate Bestway for £7m, putting drinks retailing alongside its Manchester-based Well Pharmacy.

Several business parks around the town host light industry and offices. Crewe Business Park is a 67-acre site with offices, research and IT manufacturing. Major corporations with a presence in the park include Air Products, Barclays, and Fujitsu. The 12 acre Crewe Gates Industrial Estate is adjacent to Crewe Business Park, with smaller industry including the ice cream van manufacturer Whitby Morrison. The Weston Gate area has light industry and distribution. Marshfield Bank Employment Park is to the west of the town, and includes offices, manufacturing and distribution. There are industrial and light industrial units at Radway Green.

The town has two small shopping centres: the Victoria Centre and the Market Centre. There are outdoor markets throughout the week. Grand Junction Retail Park is just outside the centre of town. Nantwich Road provides a wide range of secondary local shops, with a variety of small retailers and estate agents.

The Market Centre is the largest shopping centre in Crewe. It is situated in the heart of the town centre with a few national retailers, including B&M, Poundstretcher and Peacocks. There are three large car parks nearby and Crewe bus station is a five-minute walk from the shopping centre. It has a weekly footfall of approximately 100,000 visitors.

Developments
A planned redevelopment of Crewe's town centre, including the current bus station and main shopping area, was abandoned because of "difficult economic conditions" during 2008.

There were also plans to revamp the railway station which involved moving it to Basford. This was pending a public consultation by Network Rail scheduled for autumn 2008, but no such public consultation was done. The plan was abandoned and maintenance work was carried out on the current station instead.

Cheshire East Council developed a new regeneration master plan for Crewe, which included the opening of a new Lifestyle Centre, with a new swimming pool, gym and library.

After a £3 million refurbishment, the Crewe Market Hall re-opened its doors on 19 May 2021, the start of many new developments in Crewe.

Crewe had been planned as the site of a transport hub for the Phase 2a High Speed 2 (HS2) railway line, which received royal assent in 2021 with planned completion in 2027. The plan included a new HS2 railway station, surrounded by a commercial hub providing 37,000 jobs and 7,000 homes by 2043. However on 4 October 2023, Prime Minister Rishi Sunak announced the cancellation of this phase of the HS2 development at the Conservative Party Conference.

Railway
Crewe railway station is located less than a mile from the town centre, although it was not incorporated into the then Borough of Crewe until 1937. It is one of the largest stations in the North West and is a major interchange station on the West Coast Main Line. It has 12 platforms in use.

The station is served by several train operating companies:
 * Avanti West Coast operates inter-city trains to London Euston (average journey time of around 1 hour 35 minutes), Glasgow, Edinburgh, Manchester, Liverpool and Holyhead for the ferry connections to Dublin Port
 * Transport for Wales Rail provide services to Cardiff, Chester and Wrexham
 * London Northwestern Railway operates routes to Birmingham, Stoke-on-Trent, London and Liverpool
 * East Midlands Railway runs trains to Newark, Derby and Nottingham
 * Northern operates stopping services on two routes to Manchester Piccadilly, via Stockport and via Manchester Airport on the Styal Line.

Roads
Crewe is on the A500, A530 and A534 roads; it is located less than 5 mi from the M6 motorway.

Buses
Bus services in Crewe are operated predominantly by D&G Bus; their routes link the town with Congleton (route 42), Leighton Hospital (12), Macclesfield (38), Nantwich (84X) and Northwich (31/37).

Stagecoach Merseyside & South Lancashire runs route 84 to Chester and First Potteries operate a single service (route 3) running to Stoke-on-Trent, via Kidsgrove.

Airport
The closest airport to Crewe is Manchester Airport, which is 30 mi away; Liverpool John Lennon Airport is 40 mi away.

Culture
Crewe Heritage Centre is located in the old LMS railway yard for Crewe railway station. The museum has three signal boxes and an extensive miniature railway with steam, diesel and electric traction. The most prominent exhibit of the museum is the British Rail Class 370 Advanced Passenger Train.

The Grade II-listed Edwardian Lyceum Theatre is in the centre of Crewe. It was built in 1911 and shows drama, ballet, opera, music, comedy and pantomime. The theatre was originally located on Heath Street from 1882. The Axis Arts Centre is on the Manchester Metropolitan University (MMU) campus in Crewe. It relocated from the university's Alsager Campus when it closed. The centre has a programme of touring new performance and visual art work. The Axis centre closed at the end of the spring 2019 season with the withdrawal of MMU from the Crewe campus. The Box on Pedley Street is the town's main local music venue.

Both the Lyceum Theatre and the Axis Arts Centre feature galleries. The private Livingroom art gallery is on Prince Albert Street. The town's main library is on Prince Albert Square, opposite the Municipal Buildings.

Crewe has six Anglican churches, three Methodist, one Roman Catholic (which has a weekly Mass in Polish) and two Baptist.

There is a museum dedicated to Primitive Methodism in the nearby village of Englesea-Brook.

The Jacobean mansion Crewe Hall is located to the east of the town near Crewe Green. It is a grade I listed building, built in 1615–36 for Sir Randolph Crewe. Today, it is used as a hotel, restaurant and health club.

There is a multiplex Odeon cinema on Phoenix Leisure Park on the edge of the town centre, as well as a Mecca bingo hall and a Tenpin bowling alley.

Queens Park is the town's main park; £6.5 million was spent on its restoration in 2010. It features walkways, a children's play area, crown green bowling, putting, a boating lake, grassed areas, memorials and a café. Jubilee Gardens are in Hightown and there is also a park on Westminster Street.

In 2019, Crewe hosted Pride in the Park (previously held at Tatton Park in 2018) in Queens Park. The 2020 event, which had been due to take place on 12 September, was cancelled on 20 May, due to the COVID-19 pandemic.

Media
Local news and television programmes are provided by BBC North West and ITV Granada from the Winter Hill TV transmitter.

The weekly Crewe Chronicle and the daily Sentinel newspapers cover the town. Cheshire Live, an online news source that covers news across Cheshire, also has a section dedicated to Crewe news.

The local radio station is The Cat broadcasting on 107.9FM from the Cheshire College South and West building covering the town along with Nantwich and other local settlements. Other radio stations that cover the area include Cheshire's Silk Radio from Macclesfield, Hits Radio Staffordshire & Cheshire (formerly Signal 1) and Greatest Hits Radio Staffordshire & Cheshire from Stoke-on-Trent and BBC Radio Stoke. Nantwich-based online-only station RedShift Radio also cover the area. Sonnet Radio is a Crewe based online-only station ran by volunteers. It covers Crewe and surrounding areas broadcasting 24 hours a day, 7 days a week.

Education
Cheshire has adopted the comprehensive school model of secondary education, so all of the schools under its control cater for pupils of all levels of ability. Until the late 1970s Crewe had two grammar schools, Crewe Grammar School for Boys, now Ruskin High School and Crewe Grammar School for Girls, now the Oaks Academy (formerly Kings Grove School). The town's two other secondary schools are Sir William Stanier School, a specialist technology and arts academy, and St. Thomas More Catholic High School, specialising in mathematics and computing and modern foreign languages.

Although there are eight schools for those aged 11–16 in Crewe and its surrounding area, Cheshire College South & West is one of only two local providers of education for pupils aged 16 and over, and the only one in Crewe. The college also provides educational programmes for adults, leading to qualifications such as Higher National Diplomas (HNDs) or foundation degrees. In the 2006–07 academic year 2,532 students aged 16–18 were enrolled, along with 3,721 adults.

Manchester Metropolitan University's (MMU) Cheshire Faculty is based in Crewe, in a part of town which has been rebranded as the University Quadrant. The campus offers undergraduate and postgraduate courses in five areas: business and management, contemporary arts, exercise and sport science, interdisciplinary studies, education and teacher training. The campus underwent a £70 million investment in its facilities and buildings in 2015. The campus was used as a pre-games training camp for the London 2012 Olympic Games.

Since 2016, there has been a University Technical College for 14-19 year olds interested in automotive or railway engineering.

Sport

Crewe's local football club is Crewe Alexandra, founded in 1877 and initially managed by railway workers. During the late 20th century the club enjoyed something of a renaissance under the management of Dario Gradi, playing in the second tier of the professional pyramid for eight seasons in the late 1990s and early 2000s. Crewe Alexandra currently play in League Two (the fourth tier), having been relegated from League One in April 2022. In 2013 the club won its first major silverware after beating Southend United 2–0 in the EFL Trophy final at Wembley.

From the early 1980s, Crewe Alexandra built a reputation for developing young players through its youth ranks: England internationals Geoff Thomas, Danny Murphy, David Platt, Rob Jones and Dean Ashton, plus Northern Ireland's Neil Lennon and Steve Jones, and Wales's Robbie Savage and David Vaughan all passed through the club. Among their earlier most notable home-grown players was Frank Blunstone, born in the town in 1934, who was transferred from "The Alex" to Chelsea in 1953, and went on to win five England caps. Internationals Bruce Grobbelaar and Stan Bowles were also on the books at one time in their careers.

Crewe's local rugby clubs are both based in or near Nantwich. The Crewe & Nantwich Steamers (formerly Crewe Wolves), who played in the Rugby League Conference, were based at Barony Park, Nantwich, while Crewe and Nantwich RUFC play their home games at the Vagrants Sports Ground in Willaston.

Speedway racing was staged in Crewe in the pioneer days of the late 1920s to early 1930s; the stadium in Earle Street also operated from 1969 until 1975 when the Crewe Kings raced in British League Division Two, then the National League. At the time the track was the longest and fastest in the UK. Crewe Kings riders included Phil Crump (father of Jason Crump), Les Collins (brother of Peter Collins), Dave Morton (brother of Chris Morton), Geoff Curtis, John Jackson, Jack Millen and Dave Parry. Grand Junction Retail Park occupies the site of the now demolished stadium.

The Crewe Railroaders are the town's American football team, currently competing in the BAFA Central League Division 2 and the subject of the film Gridiron UK, which premiered at the Lyceum Theatre on 29 September 2016.

Crewe also has its own roller derby team, Railtown Loco Rollers, founded in September 2013. They skate at Sir William Stanier Leisure Centre and compete with skaters and teams from all over the North West.

Crewe's main leisure facility is the Crewe Lifestyle Centre, which now houses Crewe's main public swimming pool after the Flag Lane premises closed in 2016. Other notable leisure facilities include Sir William Stanier Leisure Centre and Victoria Community Centre.

Since 17 February 2018, Crewe's Queens Park has hosted a parkrun each Saturday morning at 9am.

Politicians

 * Thomas Nevitt (1864 in Crewe – 1932), member of the Queensland Legislative Council
 * William Edwin Wheeldon (1898 in Crewe – 1960), British co-operator and municipal politician from Birmingham and MP
 * Gwyneth Patricia Dunwoody (1930 – 2008), British Labour Party politician, MP for Exeter from 1966 to 1970, then for Crewe, later Crewe and Nantwich from 1974
 * Janet Elizabeth Ann Dean (born 1949 in Crewe), British Labour Party MP for Burton from 1997 to 2010
 * Tom Levitt (born 1954 in Crewe), Labour Party politician who was the MP for High Peak
 * Carol Jean Mountford (born 1954 in Crewe), known as Kali, Labour Party politician and MP for Colne Valley
 * Anthony Edward Timpson (born 1973), British Conservative MP for Crewe and Nantwich (2008–2017) and Eddisbury (from 2019).
 * Paul Christopher Maynard (born 1975 in Crewe), British Conservative MP for Blackpool North and Cleveleys and Rail Minister
 * Lauren Jane Moss (born 1987 in Crewe), Australian politician

Public service and commerce

 * Francis Webb (1836 – 1906) English railway engineer who, as LNWR's chief mechanical engineer, also exercised great influence in political and public life in Crewe, once being described as the 'King of Crewe'.
 * William Hope (1863 – 1933), based in Crewe, pioneer of spirit photography, member of the Crewe Circle
 * Ada Nield Chew, (1870 – 1945), suffragist, wrote a series of letters to the Crewe Chronicle, signed "A Crewe Factory Girl"
 * Blaster Bates a.k.a. Derek Macintosh Bates (1923 in Crewe – 2006), an English explosives and demolition expert and raconteur
 * Harold Hankins CBE FREng (1930 in Crewe – 2009), was a British electrical engineer and the first Vice-Chancellor of UMIST.
 * Professor Christine Dean BA. MD. FRCPsych (born in Crewe 1939), London psychiatrist, attended Crewe County Grammar School
 * Chris Hughes (born 1947), one of Britain's top quizzers, featuring in Eggheads. Lives in Crewe
 * Mark Price, Baron Price (born 1961 in Crewe), businessman, was MD of Waitrose and Deputy Chairman of John Lewis Partnership

Arts

 * William Cooper (real name Harry Summerfield Hoff) (1910 – 2002), novelist, lived at 99 Brooklyn Street
 * John Mark Ainsley (born 1963 in Crewe), English lyric tenor of baroque music and the works of Wolfgang Amadeus Mozart
 * Carl Ashmore (born 1968), children's author
 * Any Trouble, a British rock band, originating from Crewe in 1975, best known for their early 1980s recordings
 * Carey Willetts (born 1976 in Crewe), British musician, songwriter, and producer.
 * Lee Oakes (born 1976), British actor, from Haslington near Crewe
 * Mackenzie Taylor (1978–2010), British comic, writer and director. Born in Crewe
 * Adam Peter Rickitt (born 1978), English actor, singer and model and charity fundraiser

Sport

 * John Warburton (1903–?), English Football League player, mostly for Wrexham and Crewe Alexandra.
 * Frank Blunstone (born 1934 in Crewe), English footballer who played for Crewe Alexandra, Chelsea and England.
 * Sir Philip Craven MBE (born 1950), president of the International Paralympic Committee (IPC) 2001–2017, lives in Shavington.
 * Neil Brooks (born in Crewe 1962), Australian Olympic swimming gold medallist
 * John Edward Morris (born 1964), former English cricketer, played most for Derbyshire.
 * David Gilford (born 1965), European Tour and Ryder Cup golfer (1991, 1995) is from Crewe
 * Mark Rivers (born 1975 in Crewe), English footballer who played as a forward for Crewe Alexandra and Norwich City.
 * Kevin Street (born 1977 in Crewe), English footballer who played for Crewe Alexandra and Shrewsbury Town, among others.
 * Neil Critchley (born 1978 in Crewe), a former Crewe Alexandra footballer and now head coach at Blackpool.
 * Mark Cueto MBE (born 1979), former England rugby union international and player for the Sale Sharks
 * Craig Jones (1985 in Crewe – 2008), English motorcycle racer who grew up in Northwich
 * Shanaze Reade (born 1988), world BMX and track cycling champion
 * Muthu Alagappan (born c. 1990 in Crewe), medical student known in the US for his professional basketball analytics
 * Bryony Page (born 1990 in Crewe), an Olympic silver medal-winning trampolinist, raised in the village of Wrenbury, 8.5 miles from the town.

Town twinning

 * 🇩🇪 Bischofsheim, near Mainz, Germany
 * 🇵🇱 Dzierżoniów, Poland (since 2005)

title: Crewe


text:
Major appliance

A major appliance, also known as a large domestic appliance or large electric appliance or simply a large appliance, large domestic, or large electric, is a non-portable or semi-portable machine used for routine housekeeping tasks such as cooking, washing laundry, or food preservation. Such appliances are sometimes collectively known as white goods, as the products were traditionally white in colour, although a variety of colours are now available. An appliance is different from a plumbing fixture because it uses electricity or fuel.

Major appliances differ from small appliances because they are bigger and not portable. They are often considered fixtures and part of real estate and as such they are often supplied to tenants as part of otherwise unfurnished rental properties. Major appliances may have special electrical connections, connections to gas supplies, or special plumbing and ventilation arrangements that may be permanently connected to the appliance. This limits where they can be placed in a home.

Since major appliances in a home consume a significant amount of energy, they have become the objectives of programs to improve their energy efficiency in many countries. Increasing energy efficiency is often described as an important element of climate change mitigation alongside other improvements like retrofitting buildings to increase building performance. Energy efficiency improvements may require changes in construction of the appliances, or improved control systems.

Brands
In the early days of electrification, many major consumer appliances were made by the same companies that made the generation and distribution equipment. While some of these brand names persist to the present day, even if only as licensed use of old popular brand names, today many major appliances are manufactured by companies or divisions of companies that specialize in particular appliances.

Types

Major appliances may be roughly divided as follows:
 * Refrigeration equipment
 * Freezer
 * Refrigerator
 * Water cooler
 * Ice maker
 * Cooking
 * Kitchen stove, also known as a range, cooker, oven, cooking plate, or cooktop
 * Wall oven
 * Steamer oven
 * Microwave oven
 * Washing and drying equipment
 * Washing machine
 * Clothes dryer
 * Drying cabinet
 * Dishwasher
 * Heating and cooling
 * Air conditioner
 * Furnace
 * Water heater
 * Whole house ventilator
 * Mechanical Air Ventilator

title: Major appliance


text:
Aposiopesis

Aposiopesis (Classical Greek: ἀποσιώπησις, "becoming silent") is a figure of speech wherein a sentence is deliberately broken off and left unfinished, the ending to be supplied by the imagination, giving an impression of unwillingness or inability to continue. An example would be the threat "Get out, or else—!" This device often portrays its users as overcome with passion (fear, anger, excitement) or modesty. To mark the occurrence of aposiopesis with punctuation, an em-rule (—) or an ellipsis (...) may be used.

Examples

 * One classical example of aposiopesis in Virgil occurs in Aeneid 1.135. Neptune, the Roman god of the Sea, is angry with the winds, whom Juno released to start a storm and harass the Trojan hero and protagonist Aeneas. Neptune berates the winds for causing a storm without his approval, but breaks himself off mid-threat:

 * Another example in Virgil occurs in the Aeneid 2.100. Sinon, the Greek who is posing as a defector to deceive the Trojans into accepting the Trojan Horse within their city wall, tells about how Ulixes lied to spur on the war.

 * For an example from classical Latin theater, this occurs multiple times in one speech in Terence's Adelphoe, lines 159–140. In the play, Demea has two sons. He has given one to his brother Micio to raise. In the following scene, Demea has worked himself up in anger over his brother's laxer parenting style. The following speech provides multiple examples of aposiopesis:

No, you unnatural hags, I will have such revenges on you both, That all the world shall— I will do such things,— What they are, yet I know not: but they shall be The terrors of the earth. (Shakespeare, King Lear, II.iv)
 * A biblical example is found in Psalm 27, verse 13. It says: "Unless I had believed I would see the goodness of the Lord in the land of the living …" The implication is that the author does not know what he would have done.
 * King Lear, overcome by anger at his daughters, says:

Mercutio. This is the hag, when maids lie on their backs, That presses them and learns them first to bear, Making them women of good carriage: This is she— Romeo. Peace, peace, Mercutio, peace! Thou talk'st of nothing. (Shakespeare, Romeo and Juliet, I.iv)
 * Aposiopesis also occurs at the agitated climax of Mercutio's "Queen Mab" speech, resulting in a calming intervention by Romeo:

“Still it behoveth us to win the fight,” ''Began he; “else. . . Such offered us herself. . . O how I long that some one here arrive!”''
 * Dante Alighieri used an Aposiopesis in his Divine Comedy, Hell IX, 7-9 (citation from the translation by Henry Wadsworth Longfellow) (Virgil speaks to himself):

Grammatical definition
In syntax, an aposiopesis arises when the "if" clause (protasis) of a condition is stated without an ensuing "then" clause, or apodosis. Because an aposiopesis implies the trailing off of thought, it is never directly followed by a period, which would effectively result in four consecutive dots.

title: Aposiopesis


text:
Dario Gradi

Dario Gradi (born 8 July 1941) is an Italian-English former amateur football player, coach and manager. He was associated for more than 36 years with Crewe Alexandra, where he was variously manager, director of football and director of the Academy, until October 2019.

Gradi played as an amateur for clubs in the London area (and won an England amateur cap); he then took on various coaching roles in the region. His first major managerial success was achieved with Wimbledon after which he briefly managed Crystal Palace in 1981.

Gradi had a 24-year first spell as manager of Crewe between 1983 and 2007. He stepped down from his managerial role in 2007, handing first-team responsibilities to Steve Holland, and became technical director. At that time, Gradi was the longest-serving manager of an English football league club. After two further spells as Crewe manager, he finally stepped down in November 2011 to focus on the club's youth system, after managing Crewe in 1,359 first team games.

In late 2016, as the United Kingdom football sexual abuse scandal expanded, Gradi's roles at Crewe at the time of alleged offences in the 1980s and at Chelsea in the early 1970s were the subject of media scrutiny. The Chelsea allegations led to Gradi being suspended by The Football Association in November 2016. Gradi denied any wrongdoing and in February 2017 was planning an appeal against his FA suspension. However, he was heavily criticised by Chelsea's inquiry report, published in August 2019, and in the FA's Sheldon Report, published in March 2021 - when the FA said Gradi (who had retired from all football roles in October 2019) was "effectively banned for life" from football "for safeguarding reasons". While accepting he had been suspended indefinitely from certain activities, Gradi said he had not been banned. Awarded an MBE for services to football in 1998, Gradi was stripped of the award in 2023 for failing to protect children from sexual abuse.

Early life and playing career
Born to an Italian father (who died when Dario was still a child) and an English mother, Gradi moved to London, aged four, when his mother returned after the Second World War in 1945.

He attended Glyn Grammar School in Epsom, and trained as a teacher of physical education at what is now Loughborough University from 1960 to 1963 (where he played for the university's first XI football team, alongside Bob Wilson and Barry Hines), before returning to teach at his former school.

By this time he had already played as an amateur for Sutton United and for Tooting & Mitcham United in the early 1960s. He was later capped once for England's amateur side (playing in the team's British Amateur Championship tie against Scotland in Dundee in September 1967). He later rejoined Sutton United, playing in the FA Amateur Cup Final against North Shields in April 1969, and in the club's FA Cup 4th round tie against Leeds United in January 1970. Gradi also played for Wycombe Wanderers, long before the club became fully professional.

Coaching career
After a period of teaching, Gradi became a London regional coach for the FA; this caused him to lose his amateur status and become ineligible to continue his playing career. He had a spell coaching at east London's Senrab F.C., and was appointed assistant coach at Chelsea in 1971 at the age of just 29. This was followed by coaching posts at Derby County (first team coach, 1977–78), and, later, a two-year spell at Leyton Orient (youth team coach, 1981–83).

Sutton United
Gradi managed Sutton United from 1976 to 1977.

Wimbledon
He took over as manager of Wimbledon in January 1978, helping the Plough Lane side win promotion from the Football League Fourth Division in 1978–79, although they were relegated after only one season in the Third Division. They were well on course for an immediate return to the Third Division when in February 1981 an offer came for Gradi to manage struggling First Division side Crystal Palace. Palace chairman Ron Noades had only recently left Wimbledon himself and saw Gradi as the ideal man to save his new purchase from relegation.

Crystal Palace
Gradi's time at Selhurst Park was not a success, as he failed to save Crystal Palace from relegation, and he resigned the following November after a disappointing start to the 1981–82 season.

Crewe Alexandra
After a spell coaching at Leyton Orient, Gradi returned to management on 9 June 1983, when he accepted an offer to manage Crewe Alexandra, a team who regularly finished near the bottom of the Fourth Division and had been forced to apply for re-election on several occasions in order to avoid slipping into the Northern Premier League and, since its creation in 1979, the Football Conference. His first season signings included Mark Leonard from Tranmere Rovers, John Crabbe from Hereford United and David Pullar from Exeter City as Gradi looked to build an academy structure to develop players that could be sold to help fund the player development programme. Among his first transfer successes were Dave Waller (sold to Shrewsbury Town), Gary Blissett (sold to Brentford) and Geoff Thomas (sold to Crystal Palace); gradually the club moved forward.

In 1988–89, after six seasons of steady progress, they won promotion to end 25 years in the league's basement division. Gradi signed a then unheard-of ten-year contract with Crewe. They went back down again two years later, but in 1994 won promotion to Division Two and three years after that they reached Division One for the first time in their history.

Shortly after the 1994 promotion, Gradi became the League's longest-serving manager. By 2002 he was one of just two managers, the other being Alex Ferguson, to have held their position since before 1990. He later joined the club's Board of Directors.

Gradi's contract with Crewe was one of the most controversial in the Football League; it included a clause giving him a percentage of the profit on any player sold to another club.

Talent spotting
His keen eye for spotting and rearing young talent is what has gained him some recognition in football. He entered into discussions with Portugal's Benfica over the vacant managerial spot in the 1980s, and was linked with the post of FA Technical Director in 1996.

During the 1980s and 1990s Gradi helped launch the careers of many players who went on to play top division and international football. These include David Platt, Rob Jones, Geoff Thomas, Danny Murphy, Ashley Ward, Wayne Collins, Seth Johnson, Robbie Savage and Neil Lennon. Gradi's success continued into the 2000s, when he helped players including Rob Hulse, Dean Ashton, David Vaughan, Michael O'Connor, Billy Jones, Nicky Maynard and Ashley Westwood.

Crewe Alexandra won the PFA Bobby Moore Fair Play trophy 12 times in 15 years during Gradi's reign.

End of managerial career
On 20 April 2007, Gradi announced that with effect from 1 July he would relinquish first-team responsibilities, becoming technical director while gradually handing over to new first-team coach Steve Holland, with Neil Baker remaining as assistant manager. Gradi was then the longest serving manager of an English Football League club. Gradi told the club website: "I didn't want to be a 75-year-old manager working seven days a week, 52 weeks a year. That is not healthy for the future of the club. I will probably drop dead doing the job at some point but I wanted to put that day off a bit. This is a better way to do things, to introduce this gradual transition because it will take some of the workload off me."

On 18 November 2008, Gradi resumed control of Crewe's first team on a caretaker basis after a poor start to the 2008–09 season under Steve Holland had left the club bottom of League One. He was in charge for just over a month before Gudjon Thordarson was announced as his successor on Christmas Eve 2008. Gradi remained in charge of the team for two games during the Christmas period, with Thordarson taking over on 29 December. Following the sacking of Thordarson on 2 October 2009, Gradi was again reinstated as caretaker manager which the board of directors then stated would be until further notice.

After returning as manager in 2009, on 10 November 2011 it was announced that Gradi had chosen to step down as manager, returning to his position as Director of Football. Gradi's assistant manager Steve Davis, who had played for Crewe under Gradi from 1983 to 1987, was appointed as manager with immediate effect.

Gradi announced his retirement from all positions at Crewe Alexandra on 7 October 2019, at the age of 78, ending his 36-year association with the club.

Honours and tributes
In January 1998, Gradi was awarded an MBE for services to football, but was stripped of the award in 2023. In 2003 he was made an Honorary Freeman of the Borough of Crewe and Nantwich and in the same year was awarded an honorary doctorate by Loughborough University.

In 2004, Gradi won the PFA Merit Award and was inducted into the English Football Hall of Fame for his services to football. In 2011 at the Football League Awards Gradi was again honoured by his peers as he won the 'Outstanding Contribution to League Football' for his work at Crewe. A street in Crewe, Dario Gradi Drive, is named in his honour. The winning school in the Surrey Schools Football Association's boys under-13s competition receive the Dario Gradi Trophy.

UK football sexual abuse scandal
On 16 November 2016, former Crewe defender Andy Woodward revealed that he had been the victim of child sexual abuse by former football coach Barry Bennell (convicted in 1998) at the club in the 1980s. Subsequently, six other individuals contacted the police, and on 22 November, The Guardian reported that Crewe teammate Steve Walters had been another of Bennell's victims. As Gradi had been manager at the time of the abuse, and as one attack was reported to have taken place at Gradi's home but without his knowledge, Gradi was pressed to "say more about what he knew and when." On 24 November, Gradi released a statement saying he knew nothing of Bennell's crimes:

 * I would like to express sympathy to the victims of Barry Bennell not only at Crewe Alexandra, but at other clubs in the North West. The first I knew of Barry Bennell's crimes was when he was arrested in the United States in 1994. I knew nothing of his crimes before this time when he was employed by us. No-one at the Football Club knew of Bennell's crimes until his arrest in 1994 and his subsequent prosecution in the United Kingdom. The football club also co-operated fully with the authorities in 2003. The club are in the process of a review and I won't be making any further comment until this is finalised."

Also on 24 November, another ex-Crewe academy graduate Danny Murphy talked to the Evening Standard about Gradi:

 * He was an amazing, generous, caring guy but he would never cross boundaries. I felt comfortable in his company. I felt safe in his home and under his guardianship. The more time I spent at Crewe, I notice the caution he exercised within his role. ... For example, he wouldn't come into the bedroom to wake you up but he would always shout through the door. ... I hate the fact that he might be doubted in any way or even remotely linked to such negativity and bad things. My experience is totally the opposite. ... I believe that if he had known what Barry Bennell had been doing, he would have put a stop to it.

Similar character references were provided by former Crewe trainee, later Crewe Chronicle (and Cheshire Live) journalist, Peter Morse, and former defender David Wright.

On 3 December, The Independent reported an allegation from a former Chelsea youth player (later named as Eamonn Manners) that Dario Gradi, then Chelsea's assistant manager, visited the player's family's home to "smooth over" a complaint of sexual assault against Chelsea chief scout Eddie Heath in 1974. Gradi responded with a statement:

 * Aside from denying any wrongdoing, it would be inappropriate and unfair on all parties to comment piecemeal through the media at this time in connection with historic allegations. Suffice to say, I will do everything within my power to assist all investigatory authorities into what is becoming a wide-ranging and important enquiry into historic sexual abuse.

On 6 December 2016, the Football Association announced the terms of reference of a review to be conducted by Clive Sheldon QC, and said Dario Gradi would be among the first to be asked questions over the "smoothing over" allegation. In connection with these allegations, on 11 December 2016, the FA announced that it had suspended Gradi. Gradi subsequently said he had been notified by the FA of his interim suspension from football on 25 November, and reiterated "that I will do everything within my power to assist all investigatory authorities."

On 7 December, the BBC reported that the mother of a former Crewe youth team player wrote an anonymous letter to Dario Gradi in 1989–90, asking him to investigate "inappropriate" behaviour whereby a member of staff "took lots of boys into his room overnight" during a weekend away in Blackpool.

In February 2017, it was reported that Gradi planned to appeal against his FA suspension from football, feeling he had been left "in limbo", but, a year later, he remained suspended from football. On 27 February 2018, claims were made that, in 2001, a former Crewe Alexandra employee was asked by a senior official at the club to help wipe pornography off Gradi's home computer, which had been viewed by a group of Irish Under-13 players at his house.

In February 2019, The Guardian reported on a nine-page statement from Dario Gradi about what he knew regarding Barry Bennell. Gradi admitted to encouraging a close player-coach culture and to not making detailed background checks about Bennell because Crewe was trying to poach him from Manchester City "on the quiet". Club chairman John Bowler said Crewe had not appreciated the dangers of football being used as a means for a paedophile to prey on young boys ("documented procedures that are now in place for the protection of minors were not in place at that time"), while Gradi had not made detailed inquiries into Bennell's background ("He did not have any specific coaching qualifications but none were required and at the time the FA did not publish any guidance on child protection"). However, former club secretary Gill Palin had been uncomfortable about Bennell.

In August 2019, Chelsea's board apologised "unreservedly" for allowing Eddie Heath, a "prolific and manipulative sexual abuser", to operate "unchallenged". Its inquiry, led by barrister Charles Geekie QC, was also critical of former assistant manager Gradi. He was accused of failing to tell senior club staff about a sexual conduct allegation concerning Heath made by the parent of a young player. Gradi denied trying to "smooth over" the matter in a meeting with the boy's father and said he had reported the allegations to Chelsea manager Ron Suart. Gradi was accused by Geekie of giving "somewhat unlikely and unconvincing" evidence; Geekie also rejected Gradi's claim to have reported the matter to more senior staff, saying "this was a significant personal failure by Mr Gradi. It was a lost opportunity to expose Mr Heath and prevent further abuse."

The FA's 700-page Sheldon report was published on 17 March 2021, identifying failures to act adequately on complaints or rumours of sexual abuse at eight professional clubs including Crewe. Considering whether senior club people knew about Bennell, Sheldon concluded they had not received specific reports of abuse (a conclusion also reached by Cheshire constabulary). However, Norman Rowlinson, John Bowler and Hamilton Smith had discussed concerns about inappropriate behaviour; "... during Bennell's time at the Club, there were rumours circulating about [Bennell] and his sexual interest in children which were heard by some of the Club's staff, including Dario Gradi." The club "should have done more to check on the well-being of the boys", Sheldon said. Regarding the Chelsea allegations, Sheldon could not decide whether Gradi had informed the club's acting manager, Ron Suart, of concerns raised at a meeting with the player's father, but, either way, Sheldon said Gradi's or Suart's responses were inadequate. The FA's CEO Mark Bullingham said Gradi was "effectively banned for life" from football; the FA legal director said it was "for safeguarding reasons" but that was "as far as we can go". Child abuse survivors charity The Offside Trust called for Gradi to be stripped of his MBE, and for the Professional Footballers' Association and Football Hall of Fame to revoke other honours. Gradi was stripped of his MBE in August 2023, following a professional disbarment.

On 19 March 2021, Gradi apologised, saying: "I wish to express my deepest sympathy for the survivors and their families. I sincerely and personally regret that the harm being caused to these young people was not discovered at the time. I apologise for not recognising any signs of abuse at the time." He also asserted that he had not been banned from all football-related activity - "this is not the case" he said. "I am suspended indefinitely from certain specified activities with players under the age of 18 years and whilst I do not agree with it, I understand how the decision was arrived at."

Managerial statistics
1Gradi was absent from his post between 22 September and 17 October 2003, due to heart surgery. Assistant manager Neil Baker took charge of the team for this period (P6, W0, D1, L5).

Honours
Individual
 * League Two Manager of the Month: January 2011

title: Dario Gradi