Turin

Turin is surrounded by several smaller cities in the Province of Turin such as Grugliasco, Rivoli, Chivasso, Venaria, Settimo Torinese, Orbassano, Moncalieri, Avigliana, Buttigliera Alta, Gassino Torinese, Nichelino, Collegno and others, that make up one of Italy's primary metropolitan areas. Alternatively, Microchip offers COM port emulation firmware for their range of USB PIC microcontrollers. Turin produces a typical chocolate, named Gianduiotto after Gianduia, a local Commedia dell'arte mask, and many other kinds of chocolate in a host of confectioneries all around the city. FTDI Chip provides virtual COM drivers with its chips, to make the USB device look to the host software like a COM (RS-232) port. It was in Turin that Doret invented at the end of the 18th century a revolutionary machine that could make solid chocolate as we eat it now. If your Operating System and language combination is not supported, another option is a USB to RS-232 bridge. Turin is the birth place of solid chocolate. Communication between software and USB devices depends upon the Operating System (Windows, Macintosh, Linux etc) and the language you choose (Java, C++, Delphi etc).

Turin was also the city where the FISA (international rowing federation) was born in 1892. See http://www.usb.org/developers/wusb/ for more details. Among those who lost their lives was Valentino Mazzola, father of Ferruccio and Sandro Mazzola (who were also later to be football champions). Wireless USB is well suited to wireless connection of PC centric devices, just as Bluetooth is now widely used for mobile phone centric personal networks (at much lower data rates). team (at that time the most important in Europe and aka Grande Torino) hit the church of Superga, on the Turin hills. Wireless USB is intended as a cable-replacement technology, and will use Ultra wideband wireless technology for data rates of up to 480 Mbit/s. In a terrible air accident in 1949, a plane carrying the whole Torino F.C. The USB Implementers Forum is working on a wireless networking standard based on the USB protocol.

Turin has also hosted two summer Universiade the first in 1959 and 1970, in 2007 it will host the first Winter Universiade. And [Powered USB] uses standard USB signalling with the addition of extra power lines for Point of sale terminals. and Juventus, and is the host of the 2006 Winter Olympics. (However, Microsoft uses standard USB 2.0 connectivity in its newer Xbox 360.) Similarly IBM UltraPort uses standard USB signalling, but uses a proprietary connection format. The city is famous for two very sucessful football teams, Torino F.C. Microsoft's Xbox game console uses standard USB 1.1 signalling in its controllers, but features a proprietary connector rather than the standard USB connector. From April 2006 to April 2007 Turin will host a festival called "Signs of Writing" composed of events, meetings, seminars, debates, letters, and performances. It typically uses USB as the underlying communication layer.

After Alexandria, Madrid, New Delhi, Antwerp and Montreal, Turin has been chosen by UNESCO as World Book Capital for the year 2006 because of its activity of book and reading promotion, especially with the International Book Fair, one of the most important fairs in Europe of its kind. The PictBridge standard allows for interconnecting consumer imaging devices. The city is also famous for being the film set of the 1969 classic film The Italian Job starring Michael Caine - it is possible to visit all the locations on a special tour - and Deep Red (1975), directed by Italian horror filmmaker Dario Argento. Wireless USB uses UWB (Ultra Wide Band) as the radio technology. Superga can be reached by means of the Superga Rack Railway from the suburb of Sassi. Released in May 12, 2005. In the hills above the city is the basilica church of Superga, from where there is a splendid panorama of Turin against a backdrop of the snow-capped Alps. IEEE 1394b also provides rates up to approximately 3.2 Gbit/s; however, the higher rates use special physical layers which are incompatible with 1394a devices.

In 1997, this complex of historical buildings was recognised as a world heritage site by Unesco. However unlike USB Hi-Speed systems which can change the speeds on each branch a 1394a device on a 1394b system requires all devices to fall to 1394a speeds. Some of these (first and foremost Rivoli, the location of the Museum of the same name) host events, exhibitions and cultural initiatives not only of local interest. S800 requires a new physical layer, but S800 nodes can be connected to existing FireWire 1394a ports, just as USB Hi-Speed nodes will operate with older full-speed hosts. The Hunting Lodge by Juvarra can be admired in Stupinigi and there is also the royal estate in Pollenzo. This provides a new mode called S800, which operates at 786.432 Mbit/s. In the area around the city, the castles of Rivoli, Moncalieri, Venaria, Agliè, Racconigi, and Govone can be visited. In 2003, FireWire was updated with the IEEE 1394b specification.

Torino is home to Palazzo Chiablese, the Royal Armoury, the Royal Library, Palazzo Madama, Palazzo Carignano, Villa della Regina, and the Valentino Castle. Therefore if high speed transfer is what you need you should match this with a good host controller and operating system. In addition to the Royal Palace, the official residence of the Savoys until 1865, the circuit includes palaces, residences and castles in the city centre and in the surrounding towns. Reducing the maximum transfers from say the theoretical 13 per frame to 10 or 9. Turin offers a circuit of great historical and architectural interest: the Savoy Residences. In addition to this some operating systems take a conservative approach to scheduling transactions and limit the number of transfers per frame. The Museo Egizio has the most important collection of Egyptian antiquities in the world after the Cairo Museum. It is a testament to the flexibilty of the USB bus that it can handle wide variances in device performances.

The Cathedral of St John the Baptist houses the Shroud of Turin, an old linen cloth with an imprint of a man, which is believed by many to be the cloth that covered Jesus in his grave. So the sustained transfer rate is a limitation of the individual device technology not the infrastructure. One of its main symbols is the Mole Antonelliana, which hosts the National Cinema Museum of Italy. Why then can some USB devices only sustain 34 MB/s not 55 MB/s? The main reason is usually that the devices themselves are slow and spend most of the time NAK'ing the host to indicate they are not ready - this is particularly true of memory sticks. A project to build an underground system was ready in the seventies, with government funding for it and for similar projects in Milan and Rome; whilst the other two cities went ahead with the projects, Turin local gorvernment lead by major Diego Novelli shelved the proposal as it believed it to be too costly and unnecessary, but that only meant more funding for Rome and Milan. Furthermore, the host-centric nature of USB allows the host to allocate more bandwidth to high priority devices instead of forcing them to compete for bandwidth as in Firewire. In fact, the main street in the town centre ('Via Roma') runs atop a tunnel built during the fascist era (when 'Via Roma' was built); the tunnel was supposed to host the underground line but is now used as an underground car park. Conversely, for USB the maximum timing model is fixed and is limited only by the host-device branch (not the entire network).

This underground transportation project has historical importance for Turin, as the town has dreamed of an underground line for decades, the first project dating as far back as the twenties. The more devices on the bus the lower the peak performance. This first leg of the subway system links the nearby town of Collegno with the 'Porta Susa' station in Turin's town centre; the next leg extending the service to the 'Porta Nuova' railway station is expected by June 2007. The peer to peer nature of Firewire requires devices to arbitrate, which means a FireWire bus must wait until a given signal has propagated to all devices on the bus. This project is expected to continue for years and to cover a larger part of the town, but its first phase was finished in time for the Olympic Games (inaugurated on 4 February 2006 and opened to the public the day after). In a multi device environment Firewire rapidly loses ground to USB: Firewire's mixed speed networks and long connection chains dramatically affect its performance. The other major project is the construction of a subway line based on the VAL system. While for USB 2.0 the rate can be higher 55 MB/s (for a single device).

The railroad previously ran in a trench, which will now be covered by a major boulevard; the town rail station on this line will become the main station of Turin ('Porta Susa'). A single Firewire device may achieve a transfer rate for Firewire 400 as high as 41 MB/s. One is the 'Spina' ('spine') which includes the doubling of a major railroad crossing the town. USB transfer rates are generally higher than Firewire due to the need for Firewire devices to arbitrate for bus access. Some of the work sites deal with general improvements to car traffic, such as underpasses and flyovers, but two projects are of major importance and will change the shape of the town radically. USB can require more host resources than Firewire due to the need for the host to provide the arbitration and scheduling of transactions. Although this activity has increased as a result of the 2006 Winter Olympics, parts of it had long been planned. The signalling rate of USB 2.0 Hi-Speed mode is 480 megabits per second, while the signalling rate of FireWire 400 (IEEE 1394a) is 393.216 Mbit/s [4].

The town currently has a large number of rail and road work sites. These and other differences reflect the differing design goals of the two busses: USB was designed for simplicity and low cost, while FireWire was designed for high performance, particularly in time-sensitive applications such as audio and video. Most of these industries have moved to other parts of Italy, but Turin still hosts the National Museum of Cinema. The most significant technical differences between FireWire and USB include the following:. Turin is also the birthplace of major aspects of the Italian economy, such as telecommunications Telecom Italia, television (Rai, National TV channel) and cinema. FireWire retains its popularity in many professional settings, where it is used for audio and video transfer, and data storage. The future European launcher projects beyond Ariane 5 will also be managed from Turin, by the new NGL company, a subsidiary of EADS (70%) and Finmeccanica (30%). Today, USB Hi-Speed is rapidly replacing FireWire in consumer products.

Some major elements of the International Space Station, such as the Multi-Purpose Logistics Modules, were produced in Turin. The introduction of USB 2.0 Hi-Speed, with its widely advertised 480 Mbit/s signaling rate, convinced many consumers that FireWire was outdated (although this was not necessarily the case; see "USB 2.0 Hi-Speed vs FireWire" below). It is also a center for aerospace industry, with Alenia. However, because FireWire ports were more costly to implement than USB ports, primarily due to their per-port licence fee, they were rarely provided as standard equipment on computers, and peripheral manufacturers offered many more USB devices. Other companies founded in Turin are Invicta, founded 1821, Lavazza, Martini, Kappa and the chocolate factory Caffarel. USB originally operated at a far lower data rate and used much simpler hardware, and was suitable for small peripherals such as keyboards and mice. The city is home to the famous Lingotto building, which was at one time the largest car factory in the world, and is now a convention centre, concert hall, art gallery, shopping centre and hotel. USB was originally seen as a complement to FireWire, which was designed as a high-speed serial bus which could efficiently interconnect peripherals such as hard disks, audio interfaces, and video equipment.

Today the city is a major industrial centre, known particularly as home to the headquarters and main production lines of the car company Fiat. Apple computers have used USB mice and keyboards exclusively since January 1999. The population remains overwhelmingly Italian (96.1%), but there are groups like Romanian: 2.3%, Moroccans: 1.5%, Peruvians: 0.5%, Albanian: 0.4%, and others. Mouses and keyboards are frequently fitted with USB connectors, but supplied with a small USB-to-PS/2 adaptor so that they can be used with either USB or PS/2 ports. The city has seen a rise in immigrants, including the suburban areas. Joysticks, keypads, tablets and other human-interface devices are also progressively migrating from MIDI, PC game port, and PS/2 connectors to USB. Around 16.4% of the population are under 14 years over age, while those in retirement age number 18.8%. Motherboards for non-portable PCs usually have a number of USB 2.0 high-speed ports, some available at the back of the computer case, others requiring USB sockets on the front or rear of the computer to be connected via a cable to a header on the motherboard.

The city of Turin grew by 0.88% during the last 3 years, which was attributed to a somewhat low birth rate, contributing to an aging population. AT keyboard connectors are less frequently found. Three major rivers pass through the city: the Po and two of its tributaries, the Dora Riparia (from the Celtic duria meaning "water," later changed to "Duria Minor" by the Romans), and the Stura di Lanzo and Sangone. As of 2006, most PCs and motherboards have at least one USB port, but still retain PS/2 keyboard and mouse connectors. It is surrounded on the western and northern front by the Alps and on the southern front by the hills of Monferrato. Additionally, when multiple devices are connected, USB has significant advantages over FireWire,. Turin is located in northwest Italy. However, USB ports are more usual than Firewire on consumer-level computers, which enhances the compatibility of a USB drive.

See also: List of mayors of Turin. An operating system designed to handle Hi-Speed USB 2.0 optimally is capable of data rates higher than Firewire, but the most commonly found [early 2006] operating systems and drivers are not. Sergio Chiamparino, the current mayor, belongs to the center-left coalition. Additionally, some operating systems transfer blocks limited to the USB 1.1 size of 64 bytes, without taking advantage of the larger block sizes allowed by USB 2.0. The mayor of Turin is directly elected every 5 years. The main reason for this is that the tests are conducted point to point (only one device) which means the USB system is always waiting for the drive. In 2006, Turin was the home of the Olympics. FireWire tends to perform better in speed benchmark tests than even Hi-Speed USB 2.0, although the latter supports a numerically higher bit-rate.

The 2005 population is 908,000. FireWire technology is also commonly used with portable hard drives; some have both USB and FireWire ports. In the '80's the first industrial crisis hit the city and its population began to decline (and continues to, while the metropolitan area grows). Functionally, the drive appears to the user just like another internal drive.. The population reached 1 million in 1960 and peaked at 1.5 millions in 1975. These external drives usually contain a translating device that interfaces a drive of conventional technology (IDE, ATA, SATA, ATAPI, or even SCSI) to a USB port. After WWII Turin was rapidly rebuilt and its industries greatly developed, which caused waves of immigration mainly from the southern regions of Italy. Today, a number of manufacturers offer external, portable USB hard drives, or empty enclosures for drives, that offer performance comparable to internal drives.

After WWI the conflicts between worker and industrialists began, the first strikes took place and in 1920 the Lingotto factory was occupied. However, USB has one important advantage in making it possible to install and remove devices without opening the computer case, making it useful for external drives. By this time, Turin had grown to 430,000 inhabitants. USB is not intended to be a primary bus for a computer's internal storage: buses such as ATA (IDE) and SCSI fulfill that role. The Universal Exposition held in Turin in 1902 is often considered the pinnacle for Art Nouveau design, and the city hosted the Exposition again in 1911. This was initially intended for traditional magnetic and optical drives, but has been extended to support a wide variety of devices. (Since 1870 the capital has been Rome.) Turin reacted to the loss of importance, beginning a rapid industrialization: in 1899 FIAT was founded and Lancia in 1909. USB implements connections to storage devices using a set of standards called the USB mass-storage device class.

In 1865 the capital was moved to Florence. Those problems with the abuse of the USB power supply have inspired a number of April Fool hoaxes, like the introduction of a USB-powered George Foreman iGrill [2] and a desktop USB Fondue Set [3]. In 1861, Turin became the capital of the newly proclaimed United Italy. USB-powered devices attempting to draw large currents without requesting the power will not work with certain USB controllers, and will either disrupt other devices on the bus or fail to work themselves (or both). The Museo Egizio, the Mole Antonelliana, the Gran Madre church and Vittorio Veneto square were built in this period. Amongst others, a number of peripherals for IBM laptops (now made by Lenovo) are designed to use dual USB connections. The city now had 250,000 inhabitants. For portable devices where external power is not available, but not more than 1 A is required at 5 V, devices may have connectors to allow the use of two USB cables, doubling available power but reducing the number of USB ports available to other devices.

The Fréjus Tunnel was opened and made Turin an important communication node. Such devices can be used with an external power supply of adequate rating; some external hubs may, in practice, supply sufficient power. In the 19th century, after brief occupation by Napoleon, the city began to actively pursue the unification of Italy. This is a common requirement of external hard and optical disc drives and other devices with motors or lamps. Now the capitol of a European kingdom, Turin had about 90,000 inhabitants at the time. Some USB devices draw more power than is permitted by the specification for a single port. After the subsequent treaty of Utrecht, the Kingdom of Sardinia was annexed to the Duchy of Savoy and the architect Filippo Juvarra began a major redesign of the city. This can cause problems with some computers—the USB specification requires that devices connect in a low-power mode (100 mA maximum) and state how much current they need, before switching, with the host's permission, into high-power mode.

In 1706 the French besieged the city for 117 days without conquering it. In most cases, these items contain no electronic circuitry, and thus are not proper USB devices at all. Piazza San Carlo, via Po and the Royal Palace (Palazzo Reale) were built in this period. The typical example is a USB-powered reading light, but fans, battery chargers (particularly for mobile telephones) and even miniature vacuum cleaners are available. Emanuele Filiberto (Iron Head) made Turin the capital of the Duchy of Savoy in 1563. A number of devices use this power supply without participating in a proper USB network. Many of the garden and palaces were built in the 15th century when the city was redesigned; the University was also founded during this period. The host operating system typically keeps track of the power requirements of the USB network and may warn the computer's operator when a given segment requires more power than is available (and will generally shut down devices or hubs in order to keep power consumption within the available resource).

At the end of the 13th century, when it was annexed to the Duchy of Savoy, the city already had 20,000 inhabitants. When USB devices (including hubs) are first connected they are interrogated by the host controller, which inquires of each their maximum power requirements. After the fall of the Roman empire the city was conquered by the Lombards, then the Franks; it was then ruled by the Bishops. Devices that need more than 500 mA must provide their own power. Turin reached about 5,000 inhabitants at the time, all living inside the high walls. Many hubs include external power supplies which will power devices connected through them without taking power from the bus. The typical Roman street grid can still be seen in the modern city. This disallows connection of a bus-powered hub to another bus-powered hub.

(probably 28 B.C.), the Romans created a military camp (Castra Taurinorum), later dedicated to Augustus (Augusta Taurinorum). Bus-powered hubs can continue to distribute the bus provided power to connected devices but the USB specification only allows for a single level of bus-powered devices from a bus-powered hub. In the first century B.C. A bus-powered device may use as much of that power as allowed by the port it is plugged into. The area was settled by the Taurini in pre-Roman times. This is often enough to power several devices, although this budget must be shared among all devices downstream of an unpowered hub. The Italian name, Torino, happens to mean "little bull" in Italian; hence the coat of arms and the symbol of the city. A given segment of the bus is specified to deliver up to 500 mA.

The name of Turin comes from Tau, a Celtic word that means mountains. In typical situations the voltage is close to 5 V. . The compliance spec requires no more than 5.25 V anywhere and no less than 4.375 V at the worst case; a low-power function after a bus-powered hub. Turin is currently hosting the 2006 Winter Olympics. In practice, delivered voltage can drop well below 5 V, to only slightly above 4 V. mi), and one of the most populous, with 2,236,941 inhabitants at the 2004 census. The USB connector provides a single nominally 5 volt wire from which connected USB devices may power themselves.

The province is one of the largest in Italy, with 6,830 square kilometres (2,637 sq. The maximum length of a USB cable is 5 meters; greater lengths require hubs [1]. The population of Turin city is 908,000 (2004 census), but with its metropolitan area totals about 1.7 million inhabitants. Wireless USB is a standard being developed to extend the USB standard while maintaining backwards compatibility with USB 1.1 and USB 2.0 on the protocol level. Turin (Italian: Torino; Piedmontese: Turin) is a major industrial city in north-western Italy, capital of the Piedmont region, located mainly on the west bank of the Po River. USB On-The-Go has therefore defined two small form factor connectors, the mini-A and mini-B, and a hermaphroditic socket (mini-AB), which should stop the proliferation of proprietary designs. Elio Vittorini. This facility targets units such as PDAs where the USB link might connect to a PC's host port as a device in one instance, yet connect as a host itself to a keyboard and mouse device in another instance.

Germain Sommeiller. Even after the cable is hooked up and the units are talking, the two units may "swap" ends under program control. Ascanio Sobrero. An extension to USB called USB On-The-Go allows a single port to act as either a host or a device - chosen by which end of the cable plugs into the socket on the unit. Emilio Salgari. For specification purposes, these devices were treated as having a captive cable. Jean-Jacques Rousseau. Other manufacturers of small items also developed their own small form factor connector, and a wide variety of these have appeared.

Cesare Pavese. It uses a different mechanical connector while preserving the USB signaling and protocol. Vilfredo Pareto. For example, the IBM UltraPort is a proprietary USB connector located on the top of IBM's laptop LCDs. Friedrich Nietzsche. However, the mechanical layer has changed in some examples. Giulio Natta. The A-plug is approximately 4x12 mm, the B-plug is approximately 7x8 mm, and the B-mini plug is approximately 3x7 mm.

Joseph de Maistre. Thus all compliant USB cables have an A plug on one end, and either a B or Mini-B on the other end. Tulse Luper. Hosts and devices include connectors (female) while cables contain plugs (male). Cesare Lombroso. All connectors are mechanically incompatible, with an A connector always used on the upstream (host) end, and a B connector always used on the downstream (device) end. Antonio Gramsci. The USB 2.0 specification also introduces the mini-B connector, for smaller devices such as PDAs, mobile phones or digital cameras.

Natalia Ginzburg. The USB 1.0, 1.1 and 2.0 specifications define two types of connectors for the attachment of devices to the bus: A, and B. Guido Fubini. In particular:. Erasmus. The connectors which the USB committee specified were designed to support a number of USB's underlying goals, and to reflect lessons learned from the varied menagerie of connectors then in service. Luigi Einaudi. The Mini A also has an additional piece of plastic inside to prevent insertion into slave only device.

Umberto Eco. This indicates if a device supporting usb on the go (with a mini AB socket) should initially act as host, in the mini B this is open circuit. Renato Dulbecco. Pin 4 is called ID and is connected to pin 5 for a mini-A. Francesco Cirio. Most of the pins of a mini USB connector are the same as a standard USB connector, except pin 4. Gaspare Campari. This segregation is for bandwidth only; bus rules about power and hub depth still apply.

Italo Calvino. The Transaction Translator in a Hi-Speed hub (or possibly each port depending on the electrical design) will function as a completely separate Full Speed bus to Full Speed and Low Speed devices attached to it. Francesco Faà di Bruno. Hi-Speed hubs have a special function called the Transaction Translator that segregates Full Speed and Low Speed bus traffic from Hi-Speed traffic. John Bosco. Hi-Speed devices should fall back to the slower data rate of Full Speed when plugged into a Full Speed hub. St. All devices are tested according to the latest spec, so recently-compliant Low Speed devices are also 2.0.

Edmondo de Amicis. The USB-IF certifies devices and provides licenses to use special marketing logos for either "Basic-Speed" (low and full) or High-Speed after passing a compliancy test and paying a licensing fee. Victor Emmanuel II of Italy (1820-1878) - King of Piedmont and the first King of the united Italy. Though Hi-Speed devices are commonly referred to as "USB 2.0", not all USB 2.0 devices are Hi-Speed. A USB device should specify the speed it will use by correct labeling on the box it came in or sometimes on the device itself. Umberto Tozzi (1952- ) - Singer. USB supports three data rates. Massimo Taparelli, marquis d'Azeglio (1798-1866) - Statesman, novelist and painter. D+ and D− operate together; they are not separate simplex connections.

Piero Sraffa (1898-1983) Influential economist. These collectively use half-duplex differential signaling to combat the effects of electromagnetic noise on longer lines. Tullio Regge (1931- ) Physicist. USB signals are transmitted on a twisted pair of data cables, labelled D+ and D−. Aurelio Peccei (1908-1984) Founder of the Club of Rome. The most used device classes (grouped by assigned class ID) are:. Giuseppe Peano (1858-1932) Mathematician. These can be used as the main device classes are continuously revised.

Adriano Olivetti (1901-1960) Businessman. Each class also optionally supports a SubClass and Protocol subdefinition. Rita Levi-Montalcini (1909- ) Nobel Prize in physiology and medicine. If bDeviceClass is set to 0x00, the operating system will look at bInterfaceClass of each interface to determine the device class. Alessandro Martini (1812-1905) Businessman in vermouth industry. Both of these are a single byte each, so a maximum of 253 different device classes are possible (values 0x00 and 0xFF are reserved). Salvador Edward Luria (1912-1991) - Nobel Prize in physiology and medicine. If the class is to be set for the entire device, the number is assigned to the bDeviceClass field of the device descriptor, and if it is to be set for a single interface on a device, it is assigned to the bInterfaceClass field of the interface descriptor.

Primo Levi (1919-1987) - Philosopher and writer. Device classes are decided upon by the Device Working Group of the USB Implementers Forum. Carlo Levi (1902-1975) - Painter. An operating system is supposed to implement all device classes so as to provide generic drivers for any USB device. Luigi Lavazza (1859-1949) - Inventor and businessman of coffee. These classes define an expected behavior in terms of device and interface descriptors so that the same device driver may be used for any device that claims to be a member of a certain class. Vincenzo Lancia (1881-1937) - Sportsman and businessman, founder of Lancia. Devices that attach to the bus can be full-custom devices requiring a full-custom device driver to be used, or may belong to a device class.

Joseph Louis Lagrange (1736-1813) - Mathematician. On BSD systems, dmesg will show the detailed information hierarchy. Piero Gobetti (1901-1926) - Intellectual. Most Linux systems also provide the lsusb command which provides USB-specific details about ports and controllers. Sonia Gandhi (1946- ) - Politician. On Microsoft Windows platforms, one can tell whether a USB controller is version 2.0 by opening the Device Manager and checking for the word "Enhanced" in its description; only USB 2.0 drivers will contain the word "Enhanced." On Linux systems, the lspci -v command will list all PCI devices, and controllers will be named OHCI, UHCI or EHCI respectively, which is also the case in the Mac OS X system profiler. Galileo Ferraris (1847-1897) - Physicist and electrical engineer. All other vendors use virtual OHCI controllers.

Robert Fano (1917- ) - Engineer. The virtual HCD on Intel and Via EHCI controllers are UHCI. Antonio Benedetto Carpano (1764-1815) - Inventor of vermouth and apéritif. Each EHCI controller contains four virtual HCD implementations to support Full Speed and Low Speed devices. Pierre Paul Caffarel (1795-1850) - Inventor of chocolate and businessman. Only EHCI can support high-speed transfers. Norberto Bobbio (1909-2004) - Historian and philosopher. The USB 2.0 HCD implementation is called the Extended Host Controller Interface (EHCI).

Camillo Benso, count of Cavour - Politician (Italian unification). During the design phase of USB 2.0 the USB-IF insisted on only one implementation. Giuseppe Marc'Antonio Baretti (1719-1789) - Critic. The dueling implementations forced operating system vendors and hardware vendors to develop and test on both implementations which increased cost. Alessandro Baricco (1958- ) - writer. The main difference between OHCI and UHCI is the fact that UHCI is more software-driven than OHCI is, making UHCI slightly more processor-intensive but cheaper to implement (excluding the license fees). Amedeo Avogadro (1776-1856) - Physicist. VIA Technologies licensed the UHCI standard from Intel; all other chipset implementers use OHCI.

Gianni Agnelli (1921-2003) - Chairman director of FIAT and very influential Italian. However, Intel subsequently created a specification they called the Universal Host Controller Interface (UHCI) and insisted other implementers pay to license and implement UHCI. Giovanni Agnelli (1866-1945) - Founder of FIAT. Compaq's Open Host Controller Interface (OHCI) was adopted as the standard by the USB-IF. Istituto Europeo di Design (Turin) / http://www.ied.it/. At version 1.0 and 1.1 there were two competing HCD implementations. Politecnico di Torino (Turin) / http://www.polito.it/. In practice, these are hardware registers (ports) in the computer.

University of Turin (Università degli Studi di Torino) / http://www.unito.it/. The hardware that contains the host controller and the root hub has an interface toward the programmer which is called Host Controller Device (HCD) and is defined by the hardware implementer. An endpoint may however be reused among several interfaces and alternate interface settings. These interface descriptors in turn have one default interface setting and possibly more alternate interface settings which in turn have endpoint descriptors, as outlined above. Each configuration descriptor in turn has one or more interface descriptors, which describe certain aspects of the device, so that it may be used for different purposes: for example, a camera may have both audio and video interfaces.

low power mode. active vs. These configurations often correspond to states, e.g. The device connected to the bus has one (and only one) device descriptor which in turn has one or more configuration descriptors.

To access an endpoint, a hierarchical configuration must be obtained. The interrupt transfers on corresponding endpoints does not actually interrupt any traffic on the bus, they are just scheduled to be queried more often and in between any other large transfers, thus "interrupt traffic" on a USB bus is really only high-priority traffic. The host controller then polls the bus for traffic, usually in a round-robin fashion, so no device can transfer any data on the bus without explicit request from the host controller. When a device (function) or hub is attached to the host controller through any hub on the bus, it is given a unique 7 bit address on the bus by the host controller.

The pipes are also divided into four different categories by way of their transfer type:. There is always an inward and an outward pipe numbered 0 on each device. All USB devices have at least two such pipes/endpoints: namely endpoint 0 which is used to control the device on the bus. Each endpoint can transfer data in one direction only, either into or out of the device/function, so each pipe is uni-directional.

Each pipe has a maximum packet length, typically 2ⁿ bytes, so a USB packet will often contain something on the order of 8, 16, 32, 64, 128, 256, 512 or 1024 bytes. In these pipes, data is transferred in packets of varying length. (The OUT direction shall be interpreted out of the host controller and the IN direction is into the host controller.) Endpoint 0 is however reserved for the bus management in both directions and thus takes up two of the 32 endpoints. These endpoints (and their respective pipes) are numbered 0-15 in each direction, so a device/function can have up to 32 active pipes, 16 inward and 16 outward.

The pipes are synonymous to byte streams such as in the pipelines of Unix, however in USB lingo the term endpoint is (sloppily) used as a synonym for the entire pipe, even in the standard documentation. These devices/functions (and hubs) have associated pipes (logical channels) which are connections from the host controller to a logical entity on the device named an endpoint. There always exists one hub known as the root hub, which is attached directly to the host controller. The hubs are special purpose devices that are not officially considered functions.

In USB terminology devices are referred to as functions, because in theory what we know as a device may actually host several functions, such as a router that is a Secure Digital Card reader at the same time. USB connects several devices to a host controller through a chain of hubs. The specification is at revision 1.0a (Jan 2006). Smaller USB plugs and receptacles, called Mini-A and Mini-B, are also available, as specified by the On-The-Go Supplement to the USB 2.0 Specification.

Equipment conforming with any version of the standard will also work with devices designed to any of the previous specifications (backwards compatibility). Previous notable releases of the specification were 0.9, 1.0, and 1.1. The USB 2.0 specification was released in April 2000 and was standardized by the USB-IF at the end of 2001. Hewlett-Packard, Intel, Lucent, Microsoft, NEC, and Philips jointly led the initiative to develop a higher data transfer rate than the 1.1 specification.

The USB specification is at version 2.0 (with revisions) as of February 2006. Notable members have included Apple Computer, Hewlett-Packard, NEC, Microsoft, Intel, and Agere. The design of USB is standardized by the USB Implementers Forum (USB-IF), an industry standards body incorporating leading companies from the computer and electronics industries. As of 2005, the only large classes of peripherals that cannot use USB, because they need a higher data rate than USB can provide, are displays and monitors, and high-quality digital video components.

As of 2004 there were about 1 billion USB devices in the world. USB is also used extensively to connect non-networked printers, replacing the parallel ports which were widely used; USB simplifies connecting several printers to one computer. For many devices such as scanners and digital cameras, USB has become the standard connection method. USB can connect peripherals such as mice, keyboards, gamepads and joysticks, scanners, digital cameras, printers, external storage, networking components, etc.

When a device is first connected, the host enumerates and recognises it, and loads the device driver it needs. USB was designed to allow peripherals to be connected without the need to plug expansion cards into the computer's ISA, EISA, or PCI bus, and to improve plug-and-play capabilities by allowing devices to be hot-swapped (connected or disconnected without powering down or rebooting the computer). USB cables do not need to be terminated. Modern computers often have several host controllers, allowing a very large number of USB devices to be connected.

Not more than 127 devices, including the bus devices, may be connected to a single host controller. Additional USB hubs may be included in the chain, allowing branching into a tree structure, subject to a limit of 5 levels of branching per controller. A USB system has an asymmetric design, consisting of a host controller and multiple daisy-chained devices. .

Universal Serial Bus (USB) provides a serial bus standard for connecting devices, usually to computers such as PCs and the Apple Macintosh, but is also becoming commonplace on video game consoles such as Sony's PlayStation 2, Microsoft's Xbox 360, Nintendo's Revolution, and PDAs, and even devices like televisions and home stereo equipment. It appears that no work has been done on this package since 2003 so it may be abandoned. The usb.windows package has a partial Windows implementation of a usb.core.Host object, bootstrapping support, and other classes leveraging Windows USB support. Java - The Mike Stahl started work on this combination in 2003.

Java development is possible via JNI. Their COM interface allows for Delphi, C# and VB development. General - USBIO has C++ drivers for USB communication on windows from C & C++. Java - No info is available on this combination.

General - Apple has this page on General Mac USB Development. This API is unfortunately limited to Linux. Java - The jUSB project provides a Free Software (and Open Source) Java API for USB, supporting applications using Java host-side software to drive USB devices. General - http://www.linux-usb.org/.

This is the current revision. USB On-The-Go Supplement 1.0a: Released in June 2003. USB On-The-Go Supplement 1.0: Released in December 2001. As an example, a computer's port could be incapable of USB 2.0's hi-speed fast transfer rates, but still claim USB 2.0 compliance (since it supports some of USB 2.0).

This makes the backwards compatibility explicit, but it becomes more difficult to determine a device's throughput without seeing the symbol. Added three speed distinction to this standard, allowing all devices to be USB 2.0 compliant even if they were previously considered only 1.1 or 1.0 compliant. USB 2.0: Revised in December 2002. This is the current revision.

The major feature of this standard was the addition of high-speed mode. USB 2.0: Released in April 2000. USB 1.1: Released in September 1998. USB 1.0: Released in January 1996.

USB 1.0 FDR: Released in November 1995, the same year that Apple adopted the IEEE 1394 standard known as FireWire. In a FireWire network, any capable node can control the network. A USB network relies on a single host at the top of the tree to control the network. A FireWire device can communicate with any other node at any time, subject to network conditions.

USB uses a "speak-when-spoken-to" protocol; peripherals cannot communicate with the host unless the host specifically requests communication. USB networks use a tiered-star topology, while FireWire networks use a repeater-based topology. Compliant devices must either fit within the size restrictions or support a compliant extension cable which does. This was done to avoid circumstances where a device complied with the connector specification but its large size blocked adjacent ports.

Unlike most other connector standards, the USB spec also defines limits to the size of a connecting device in the area around its plug. The USB standard specifies relatively low tolerances for compliant USB connectors, intending to minimize incompatibilities in connectors produced by different vendors (a goal that has been very successfully achieved). This type of enclosure also means that there is a (moderate) degree of protection from electromagnetic interference afforded to the USB signal while it travels through the mated connector pair (this is the only location when the otherwise twisted data pair must travel a distance in parallel). This sheath is typically connected to the system ground, allowing otherwise damaging static charges to be safely discharged by this route (rather than via delicate electronic components).

The connector construction always ensures that the external sheath on the plug contacts with its counterpart in the receptacle before the four connectors within are connected. The force needed to make or break a connection is modest, allowing connections to be made in awkward circumstances or by those with motor disabilities. USB cables and small USB devices are held in place by the gripping force from the receptacle (without the need for the screws, clips, or thumbturns other connectors require). A moderate insertion/removal force is specified.

RJ-45 cabling) gender-changers are never used, making it difficult to create a cyclic USB network. Unlike other communications systems (e.g. USB does not support cyclical networks, so the connectors from incompatible USB devices are themselves incompatible. The connectors enforce the directed topology of a USB network.

The connectors are particularly cheap to manufacture. However, it is not obvious at a glance to the inexperienced user which way round a connector goes, so it is often necessary to try both ways. Connectors cannot be plugged-in upside down, and it is clear from the appearance and kinesthetic sensation of making a connection when the plug and socket are correctly mated. It is difficult to incorrectly attach a USB connector.

The encasing sheath and the tough moulded plug body mean that a connector can be dropped, stepped upon, even crushed or struck, all without damage; a considerable degree of force is needed to significantly damage a USB connector. As a result USB connectors can safely be handled, inserted, and removed, even by a small child. The electrical contacts in a USB connector are protected by an adjacent plastic tongue, and the entire connecting assembly is further protected by an enclosing metal sheath. Many previous connector designs were fragile, with pins or other delicate components prone to bending or breaking, even with the application of only very modest force.

The connectors are designed to be robust. A Hi-Speed rate of 480 Mbit/s (57 MiB/s). All USB Hubs support Full Speed. Full Speed devices divide the USB bandwidth between them in a first-come first-served basis and it is not uncommon to run out of bandwidth with several isochronous devices.

Full Speed was the fastest rate before the USB 2.0 specification and many devices fall back to Full Speed. A Full Speed rate of 12 Mbit/s (1.4 MiB/s). A Low Speed rate of 1.5 Mbit/s (183 KiB/s) that is mostly used for Human Interface Devices (HID) such as keyboards, mice and joysticks. file transfers.

bulk transfers - large sporadic transfers using all remaining available bandwidth (but with no guarantees on bandwidth or latency), e.g. pointing devices and keyboards. interrupt transfers - devices that need guaranteed quick responses (bounded latency), e.g. realtime audio or video.

isochronous transfers - at some guaranteed speed (often but not necessarily as fast as possible) but with possible data loss, e.g. by the bus control pipe number 0. control transfers - typically used for short, simple commands to the device, and a status response, used e.g.