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79-784: The idea of a stateless desktop was a significant shift from, and the eventual successor to, Sun's earlier line of diskless Java -only desktops, the JavaStation . The concept began in Sun Microsystems Laboratories in 1997 as a project codenamed NetWorkTerminal (NeWT). The client was designed to be small, low cost, low power, and silent. It was based on the Sun Microelectronics MicroSPARC IIep . Other processors initially considered for it included Intel's StrongARM , Philips Semiconductors ' TriMedia , and National Semiconductor 's Geode . The MicroSPARC IIep

158-555: A Virtual Machine (VDI) . This setup is flexible and works well in many environments because the intermediate Sun Ray Server layer is transparent to the Windows desktop. At the same time however, this transparency can also become an issue for software that is location dependent. If location dependent information needs to be added it is possible to extend the functionality of the Sun Ray software with additional custom scripts. The Sun Ray Wiki offers

237-450: A captive portal webpage for access. Organizations, enthusiasts, authorities and businesses , such as airports, hotels, and restaurants, often provide free or paid-use hotspots to attract customers, to provide services to promote business in selected areas. Routers often incorporate a digital subscriber line modem or a cable modem and a Wi-Fi access point, are frequently set up in homes and other buildings, to provide Internet access for

316-489: A disk image to the local hard drive. After the bootstrapping process has been initiated, as described above, bootstrapping will take place according to one of three main approaches. This third approach makes it easier to use client OS than having a complete disk image in RAM or using a read-only file system. In this approach, the system uses some "write cache" that stores every data that a diskless node has written. This write cache

395-420: A server . (A computer may also be said to act as a diskless node , if its disks are unused and network booting is used.) Diskless nodes (or computers acting as such) are sometimes known as network computers or hybrid clients . Hybrid client may either just mean diskless node, or it may be used in a more particular sense to mean a diskless node which runs some , but not all, applications remotely, as in

474-494: A "Follow Me Printing" setup as an example, e.g. a user always gets the nearest printer as default printer when going from room-to-room or location-to-location, also inside their Windows session. It is relatively easy for an administrator to extend and add to this functionality as required. Diskless node A diskless node (or diskless workstation ) is a workstation or personal computer without disk drives , which employs network booting to load its operating system from

553-580: A 100 MHz MicroSPARC IIep processor, followed by a custom SoC version codenamed Copernicus (US 6,993,617 B2), which was based on the MicroSPARC IIep core, but added 4 MiB of on-chip DRAM, USB, and a smart card interface in addition to the memory controller and PCI interface already on the MicroSPARC IIep. The Sun Ray 2 and 3 clients use the MIPS architecture -based RMI Alchemy Au1550 processor . A pure software implementation, Sun Desktop Access Client ,

632-415: A 1:N relationship (1 disk image used simultaneously by N diskless nodes). This makes it very easy to install and maintain software applications: The administrator needs to install or maintain the application only once, and the clients can get the new application as soon as they boot off the updated image. Disk image sharing is made possible because they use the write cache: No client competes for any writing in

711-626: A Wi-Fi network. Wi-Fi uses a large number of patents held by many different organizations. Australia, the United States and the Netherlands simultaneously claim the invention of Wi-Fi, and a consensus has not been reached globally. In 2009, the Australian CSIRO was awarded $ 200 million after a patent settlement with 14 technology companies, with a further $ 220 million awarded in 2012 after legal proceedings with 23 companies. In 2016,

790-447: A city-wide campaign to convert old phone booths into digital kiosks in 2014. The project, titled LinkNYC , has created a network of kiosks that serve as public Wi-Fi hotspots, high-definition screens and landlines . Installation of the screens began in late 2015. The city government plans to implement more than seven thousand kiosks over time, eventually making LinkNYC the largest and fastest public, government-operated Wi-Fi network in

869-456: A common Wi-Fi version. The versions differ between the radio wavebands they operate on, the radio bandwidth they occupy, the maximum data rates they can support and other details. Some versions permit the use of multiple antennas, which permits greater speeds as well as reduced interference. Historically, the equipment listed the versions of Wi-Fi supported using the name of the IEEE standards. In 2018,

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948-407: A computer and an interface controller is called a station . Stations are identified by one or more MAC addresses . Wi-Fi nodes often operate in infrastructure mode in which all communications go through a base station. Ad hoc mode refers to devices communicating directly with each other, without communicating with an access point. A service set is the set of all the devices associated with

1027-410: A diskless model will not necessarily cause a noticeable degradation in performance. Greater network bandwidth (i.e. capacity) will also be used in a diskless model, compared to a fat client model. This does not necessarily mean that a higher capacity network infrastructure will need to be installed—it could simply mean that a higher proportion of the existing network capacity will be used. Finally,

1106-435: A diskless node is loaded from a server, using network booting . In some cases, removable storage may be used to initiate the bootstrap process, such as a USB flash drive , or other bootable media such as a floppy disk , CD or DVD. However, the firmware in many modern computers can be configured to locate a server and begin the bootup process automatically, without the need to insert bootable media. For network auto-booting,

1185-539: A founding member of the Wi-Fi Alliance, the term Wi-Fi was chosen from a list of ten names that Interbrand proposed. Interbrand also created the Wi-Fi logo . The yin-yang Wi-Fi logo indicates the certification of a product for interoperability . The name is often written as WiFi , Wifi , or wifi , but these are not approved by the Wi-Fi Alliance. The name Wi-Fi is not short-form for 'Wireless Fidelity', although

1264-641: A greater degree by common building materials than the 2.4 GHz bands and usually give a shorter range. As 802.11 specifications evolved to support higher throughput, the protocols have become much more efficient in their bandwidth use. Additionally, they have gained the ability to aggregate channels together to gain still more throughput where the bandwidth for additional channels is available. 802.11n allows for double radio spectrum bandwidth (40 MHz) per channel compared to 802.11a or 802.11g (20 MHz). 802.11n can be set to limit itself to 20 MHz bandwidth to prevent interference in dense communities. In

1343-459: A local hard drive . Diskless nodes process data , thus using their own CPU and RAM to run software , but do not store data persistently—that task is handed off to a server. This is distinct from thin clients , in which all significant processing happens remotely, on the server—the only software that runs on a thin client is the "thin" (i.e. relatively small and simple) client software, which handles simple input/output tasks to communicate with

1422-426: A particular Wi-Fi network. Devices in a service set need not be on the same wavebands or channels. A service set can be local, independent, extended, mesh, or a combination. Each service set has an associated identifier, a 32-byte service set identifier (SSID), which identifies the network. The SSID is configured within the devices that are part of the network. A basic service set (BSS) is a group of stations that share

1501-428: A price. As often happens in computing, increased storage efficiency sometimes comes at the price of decreased performance. Large numbers of nodes making demands on the same server simultaneously can slow down everyone's experience. However, this can be mitigated by installing large amounts of RAM on the server (which speeds up read operations by improving caching performance), by adding more servers (which distributes

1580-478: A separate network display protocol, Appliance Link Protocol (ALP), for the Sun Ray system. VMware announced support for the protocol by VMware View in 2008. The Sun Ray Software has two basic modes of operation: generic session or kiosk mode . In a generic session, the user will see the Solaris or Linux login screen of the operating system that is running SRS. In kiosk mode, the login screen varies depending on

1659-806: A shared disk image, because each client writes to its own cache. All the modern diskless nodes systems can also use a 1:1 Client-to-DiskImage relationship, where one client "owns" one disk image and writes directly into said disk image. No write cache is used then. Making a modification in a shared disk image is usually made this way: The use of central disk storage also makes more efficient use of disk storage. This can cut storage costs, freeing up capital to invest in more reliable, modern storage technologies, such as RAID arrays which support redundant operation, and storage area networks which allow hot-adding of storage without any interruption. Further, it means that losses of disk drives to mechanical or electrical failure—which are statistically highly probable events over

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1738-410: A single carrier, whereas 802.11a, Wi-Fi 4, 5 and 6 use orthogonal frequency-division multiplexing . Channels are used half duplex and can be time-shared by multiple networks. Any packet sent by one computer is locally received by stations tuned to that channel, even if that information is intended for just one destination. Stations typically ignore information not addressed to them. The use of

1817-600: A situation where a diskless node would be useful is in a possibly hazardous environment where computers are likely to be damaged or destroyed, thus making the need for inexpensive nodes, and minimal hardware a benefit. Again, thin clients can also be used here. Diskless machines may also consume little power and make little noise, which implies potential environmental benefits and makes them ideal for some computer cluster applications. Both thin client and diskless node architectures employ diskless clients which have advantages over fat clients (see above), but differ with regard to

1896-613: A team of scientists began working on wireless LAN technology. A prototype test bed for a wireless local area network (WLAN) was developed in 1992 by a team of researchers from the Radiophysics Division of the CSIRO (Commonwealth Scientific and Industrial Research Organisation) in Australia, led by John O'Sullivan . A patent for Wi Fi was lodged by the CSIRO in 1992 The first version of

1975-462: A timeframe of years, with a large number of disks involved—are often both less likely to happen (because there are typically fewer disk drives that can fail) and less likely to cause interruption (because they would likely be part of RAID arrays). This also means that the nodes themselves are less likely to have hardware failures than fat clients . Diskless nodes share these advantages with thin clients . However, this storage efficiency can come at

2054-615: A wider channel for higher throughput. Countries apply their own regulations to the allowable channels, allowed users and maximum power levels within these frequency ranges. 802.11b/g/n can use the 2.4 GHz band, operating in the United States under FCC Part 15 rules and regulations. In this frequency band, equipment may occasionally suffer interference from microwave ovens, cordless telephones , USB 3.0 hubs, Bluetooth and other devices. Spectrum assignments and operational limitations are not consistent worldwide: Australia and Europe allow for an additional two channels (12, 13) beyond

2133-562: Is a trademark of the Wi-Fi Alliance , which restricts the use of the term " Wi-Fi Certified " to products that successfully complete interoperability certification testing. Non-compliant hardware is simply referred to as WLAN , and it may or may not work with " Wi-Fi Certified " devices. As of 2017, the Wi-Fi Alliance consisted of more than 800 companies from around the world. As of 2019, over 3.05 billion Wi-Fi-enabled devices are shipped globally each year. Wi-Fi uses multiple parts of

2212-554: Is about 20 m (66 ft) indoors, while some access points claim up to a 150 m (490 ft) range outdoors. Hotspot coverage can be as small as a single room with walls that block radio waves or as large as many square kilometers using many overlapping access points with roaming permitted between them. Over time, the speed and spectral efficiency of Wi-Fi have increased. As of 2019, some versions of Wi-Fi, running on suitable hardware at close range, can achieve speeds of 9.6 Gbit/s ( gigabit per second). A 1985 ruling by

2291-432: Is divided into a multitude of channels . In the standards, channels are numbered at 5 MHz spacing within a band (except in the 60 GHz band, where they are 2.16 GHz apart), and the number refers to the centre frequency of the channel. Although channels are numbered at 5 MHz spacing, transmitters generally occupy at least 20 MHz, and standards allow for neighbouring channels to be bonded together to form

2370-620: Is submitted for certification. The lack of Wi-Fi certification does not necessarily imply that a device is incompatible with other Wi-Fi devices. The Wi-Fi Alliance may or may not sanction derivative terms, such as Super Wi-Fi , coined by the US Federal Communications Commission (FCC) to describe proposed networking in the UHF TV band in the US. Equipment frequently supports multiple versions of Wi-Fi. To communicate, devices must use

2449-417: Is used in applications such as motion detection and gesture recognition . Wi-Fi stations communicate by sending each other data packets , blocks of data individually sent and delivered over radio on various channels. As with all radio, this is done by the modulation and demodulation of carrier waves . Different versions of Wi-Fi use different techniques, 802.11b uses direct-sequence spread spectrum on

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2528-503: Is usually a file, stored on a server (or on the client storage if any). It can also be a portion of the client RAM. This write cache can be persistent or volatile. When volatile, all the data that has been written by a specific client to the virtual disk are dismissed when said client is rebooted, and yet, user data can remain persistent if recorded in user (roaming) profiles or home folders (that are stored on remote servers). The two major commercial products (the one from Hewlett-Packard , and

2607-542: The Eduroam international authentication infrastructure. In the early 2000s, many cities around the world announced plans to construct citywide Wi-Fi networks. There are many successful examples; in 2004, Mysore (Mysuru) became India's first Wi-Fi-enabled city. A company called WiFiyNet has set up hotspots in Mysore, covering the whole city and a few nearby villages. In 2005, St. Cloud, Florida and Sunnyvale, California , became

2686-546: The IEEE 802 protocol family and is designed to work seamlessly with its wired sibling, Ethernet . Compatible devices can network through wireless access points with each other as well as with wired devices and the Internet. Different versions of Wi-Fi are specified by various IEEE 802.11 protocol standards, with different radio technologies determining radio bands, maximum ranges, and speeds that may be achieved. Wi-Fi most commonly uses

2765-645: The Preboot Execution Environment (PXE) or Bootstrap Protocol (BOOTP) network protocols are commonly used to find a server with files for booting the device. Standard full-size desktop PCs are able to be network-booted in this manner with an add-on network card that includes a Universal Network Device Interface boot ROM. Diskless network booting is commonly a built-in feature of desktop and laptop PCs intended for business use, since it can be used on an otherwise disk-booted standard desktop computer to remotely run diagnostics, to install software, or to apply

2844-853: The Wi-Fi Alliance introduced simplified Wi-Fi generational numbering to indicate equipment that supports Wi-Fi 4 ( 802.11n ), Wi-Fi 5 ( 802.11ac ) and Wi-Fi 6 ( 802.11ax ). These generations have a high degree of backward compatibility with previous versions. The alliance has stated that the generational level 4, 5, or 6 can be indicated in the user interface when connected, along with the signal strength. The most important standards affecting Wi‑Fi are: 802.11a, 802.11b, 802.11g, 802.11n ( Wi-Fi 4 ), 802.11h, 802.11i, 802.11-2007, 802.11–2012, 802.11ac ( Wi-Fi 5 ), 802.11ad, 802.11af, 802.11-2016, 802.11ah, 802.11ai, 802.11aj, 802.11aq , 802.11ax ( Wi-Fi 6 ), 802.11ay . Wi-Fi technology may be used to provide local network and Internet access to devices that are within Wi-Fi range of one or more routers that are connected to

2923-562: The Windows product line: Windows 95 OSR2 and Windows 98 were supported by Qualystem and Lanworks, Windows NT was supported by APCT and Ardence (called VenturCom at that time), and Windows 2000/XP/2003/Vista/Windows 7 are supported by Hewlett-Packard (which acquired Neoware which had previously acquired Qualystem) and Citrix Systems (which acquired Ardence ). With essentially a single OS image for an array of machines (with perhaps some customizations for differences in hardware configurations among

3002-498: The thin client computing architecture. Advantages of diskless nodes can include lower production cost, lower running costs, quieter operation, and manageability advantages (for example, centrally managed software installation). In many universities and in some large organizations, PCs are used in a similar configuration, with some or all applications stored remotely but executed locally—again, for manageability reasons. However, these are not diskless nodes if they still boot from

3081-455: The 11 permitted in the United States for the 2.4 GHz band, while Japan has three more (12–14). 802.11a/h/j/n/ac/ax can use the 5 GHz U-NII band , which, for much of the world, offers at least 23 non-overlapping 20 MHz channels. This is in contrast to the 2.4 GHz frequency band where the channels are only 5 MHz wide. In general, lower frequencies have longer range but have less capacity. The 5 GHz bands are absorbed to

3160-608: The 2.4 gigahertz (120 mm) UHF and 5 gigahertz (60 mm) SHF radio bands, with the 6 gigahertz SHF band used in newer generations of the standard; these bands are subdivided into multiple channels. Channels can be shared between networks, but, within range, only one transmitter can transmit on a channel at a time. Wi-Fi's radio bands work best for line-of-sight use. Many common obstructions, such as walls, pillars, home appliances, etc., may greatly reduce range, but this also helps minimize interference between different networks in crowded environments. The range of an access point

3239-408: The 5 GHz band, 20 MHz, 40 MHz, 80 MHz, and 160 MHz channels are permitted with some restrictions, giving much faster connections. Wi-Fi is part of the IEEE 802 protocol family. The data is organized into 802.11 frames that are very similar to Ethernet frames at the data link layer, but with extra address fields. MAC addresses are used as network addresses for routing over

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3318-427: The 802.11 protocol was released in 1997, and provided up to 2 Mbit/s link speeds. This was updated in 1999 with 802.11b to permit 11 Mbit/s link speeds. In 1999, the Wi-Fi Alliance formed as a trade association to hold the Wi-Fi trademark under which most IEEE 802.11 products are sold. The major commercial breakthrough came with Apple Inc. adopting Wi-Fi for their iBook series of laptops in 1999. It

3397-562: The CSIRO's WLAN prototype test bed was chosen as Australia's contribution to the exhibition A History of the World in 100 Objects held in the National Museum of Australia . The name Wi-Fi , commercially used at least as early as August 1999, was coined by the brand-consulting firm Interbrand. The Wi-Fi Alliance had hired Interbrand to create a name that was "a little catchier than 'IEEE 802.11b Direct Sequence'." According to Phil Belanger,

3476-484: The I/O workload), or by adding more disks to a RAID array (which distributes the physical I/O workload). In any case this is also a problem which can affect any client-server network to some extent, since, of course, fat clients also use servers to store user data. Indeed, user data may be much more significant in size and may be accessed far more frequently than operating systems and programs in some environments, so moving to

3555-611: The Internet. The coverage of one or more interconnected access points can extend from an area as small as a few rooms to as large as many square kilometres. Coverage in the larger area may require a group of access points with overlapping coverage. For example, public outdoor Wi-Fi technology has been used successfully in wireless mesh networks in London. An international example is Fon . Wi-Fi provides services in private homes, businesses, as well as in public spaces. Wi-Fi hotspots may be set up either free of charge or commercially, often using

3634-578: The LAN. Wi-Fi's MAC and physical layer (PHY) specifications are defined by IEEE 802.11 for modulating and receiving one or more carrier waves to transmit the data in the infrared, and 2.4, 3.6 , 5, 6, or 60 GHz frequency bands. They are created and maintained by the IEEE LAN/MAN Standards Committee ( IEEE 802 ). The base version of the standard was released in 1997 and has had many subsequent amendments. The standard and amendments provide

3713-441: The Sun Ray 2FS with 28" (2048 × 2048), 30" (2560 × 1600) and 56" (3840 × 2160) displays; in 2008 they trialed an external graphics accelerator that enables the Sun Ray to be used with any high resolution display. The Sun Ray 3 models were the last in production; last order date February 28, 2014; last ship date August 31, 2014. Sun's OEM partners produced Wi-Fi notebook versions of Sun Ray: The Sun Ray 1 clients initially used

3792-554: The U.S. Federal Communications Commission released parts of the ISM bands for unlicensed use for communications. These frequency bands include the same 2.4 GHz bands used by equipment such as microwave ovens , and are thus subject to interference. In 1991 in Nieuwegein , the NCR Corporation and AT&T invented the precursor to 802.11, intended for use in cashier systems, under

3871-543: The Wi-Fi Alliance did use the advertising slogan "The Standard for Wireless Fidelity" for a short time after the brand name was created, and the Wi-Fi Alliance was also called the "Wireless Fidelity Alliance Inc." in some publications. IEEE is a separate, but related, organization and their website has stated "WiFi is a short name for Wireless Fidelity". The name Wi-Fi was partly chosen because it sounds similar to Hi-Fi , which consumers take to mean high fidelity or high quality . Interbrand hoped consumers would find

3950-605: The basis for wireless network products using the Wi-Fi brand. While each amendment is officially revoked when incorporated in the latest version of the standard, the corporate world tends to market to the revisions because they concisely denote capabilities of their products. As a result, in the market place, each revision tends to become its own standard. In addition to 802.11, the IEEE 802 protocol family has specific provisions for Wi-Fi. These are required because Ethernet's cable-based media are not usually shared, whereas with wireless all transmissions are received by all stations within

4029-481: The capability. Some laptops that have a cellular modem card can also act as mobile Internet Wi-Fi access points. Many traditional university campuses in the developed world provide at least partial Wi-Fi coverage. Carnegie Mellon University built the first campus-wide wireless Internet network, called Wireless Andrew , at its Pittsburgh campus in 1993 before Wi-Fi branding existed. Many universities collaborate in providing Wi-Fi access to students and staff through

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4108-569: The channel to be idle at the same time and thus begin transmission simultaneously. A collision happens when a station receives signals from multiple stations on a channel at the same time. This corrupts the transmitted data and can require stations to re-transmit. The lost data and re-transmission reduces throughput, in some cases severely. The 802.11 standard provides several distinct radio frequency ranges for use in Wi-Fi communications: 900  MHz , 2.4 GHz, 3.6 GHz, 4.9 GHz, 5 GHz, 6 GHz and 60 GHz bands . Each range

4187-445: The clients. Diskless nodes can be seen as a compromise between fat clients (such as ordinary personal computers) and centralized computing, using central storage for efficiency, but not requiring centralized processing, and making efficient use of the powerful processing power of even the slowest of contemporary CPUs, which would tend to sit idle for much of the time under the centralized computing model. The operating system (OS) for

4266-414: The combination of network data transfer latencies (physically transferring the data over the network) and contention latencies (waiting for the server to process other nodes' requests before yours) can lead to an unacceptable degradation in performance compared to using local drives, depending on the nature of the application and the capacity of the network infrastructure and the server. Another example of

4345-515: The database. Signal fluctuations can cause errors, which can be reduced with noise-filtering techniques. For low precision, integrating Wi-Fi data with geographical and time information has been proposed. The Wi-Fi RTT capability introduced in IEEE 802.11mc allows for positioning based on round trip time measurement, an improvement over the RSSI method. The IEEE 802.11az standard promises further improvements in geolocation accuracy. Wi-Fi sensing

4424-414: The first cities in the United States to offer citywide free Wi-Fi (from MetroFi ). Minneapolis has generated $ 1.2 million in profit annually for its provider . In May 2010, the then London mayor Boris Johnson pledged to have London-wide Wi-Fi by 2012. Several boroughs including Westminster and Islington already had extensive outdoor Wi-Fi coverage at that point. New York City announced

4503-613: The location of processing. Wi-Fi Wi-Fi ( / ˈ w aɪ f aɪ / ) is a family of wireless network protocols based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio waves . These are the most widely used computer networks, used globally in home and small office networks to link devices and to provide Internet access with wireless routers and wireless access points in public places such as coffee shops, hotels, libraries, and airports. Wi-Fi

4582-530: The name WaveLAN . NCR's Vic Hayes , who held the chair of IEEE 802.11 for ten years, along with Bell Labs engineer Bruce Tuch, approached the Institute of Electrical and Electronics Engineers (IEEE) to create a standard and were involved in designing the initial 802.11b and 802.11a specifications within the IEEE. They have both been subsequently inducted into the Wi-Fi NOW Hall of Fame. In 1989 in Australia,

4661-452: The name catchy, and that they would assume this wireless protocol has high fidelity because of its name. Other technologies intended for fixed points, including Motorola Canopy , are usually called fixed wireless . Alternative wireless technologies include Zigbee , Z-Wave , Bluetooth and mobile phone standards . To connect to a Wi-Fi LAN, a computer must be equipped with a wireless network interface controller . The combination of

4740-527: The nodes), installing software and maintaining installed software can be more efficient. Furthermore, any system changes made during operation (due to user action, worms, viruses, etc.) can be either wiped out when the power is removed (if the image is copied to a local RAM disk) such as Windows XP Embedded remote boot or prohibited entirely (if the image is a network filesystem). This allows use in public access areas (such as libraries ) or in schools etc., where users might wish to experiment or attempt to "hack"

4819-656: The other one from Citrix Systems ) that allow the deployment of Diskless Nodes that can boot Microsoft Windows or Linux client OS use such write caches. The Citrix product cannot use persistent write cache, but VHD and HP product can. Windows 3.x and Windows 95 OSR1 supported Remote Boot operations, from NetWare servers, Windows NT Servers and even DEC Pathworks servers. Third party software vendors such as Qualystem (acquired by Neoware ), LanWorks (acquired by 3Com ), Ardence (acquired by Citrix Systems ), APCT and Xtreamining Technology have developed and marketed software products aimed to remote-boot newer versions of

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4898-566: The project, which was to be completed in 2015. Wi-Fi positioning systems use known positions of Wi-Fi hotspots to identify a device's location. It is used when GPS isn't suitable due to issues like signal interference or slow satellite acquisition. This includes assisted GPS , urban hotspot databases, and indoor positioning systems. Wi-Fi positioning relies on measuring signal strength ( RSSI ) and fingerprinting. Parameters like SSID and MAC address are crucial for identifying access points. The accuracy depends on nearby access points in

4977-542: The range that employ that radio channel. While Ethernet has essentially negligible error rates, wireless communication media are subject to significant interference. Therefore, the accurate transmission is not guaranteed so delivery is, therefore, a best-effort delivery mechanism. Because of this, for Wi-Fi, the Logical Link Control (LLC) specified by IEEE 802.2 employs Wi-Fi's media access control (MAC) protocols to manage retries without relying on higher levels of

5056-504: The receiver uses the destination address to determine whether the transmission is relevant to the station or should be ignored. A scheme known as carrier-sense multiple access with collision avoidance (CSMA/CA) governs the way stations share channels. With CSMA/CA stations attempt to avoid collisions by beginning transmission only after the channel is sensed to be idle, but then transmit their packet data in its entirety. CSMA/CA cannot completely prevent collisions, as two stations may sense

5135-400: The same channel also means that the data bandwidth is shared, so for example, available throughput to each device is halved when two stations are actively transmitting. As with other IEEE 802 LANs, stations come programmed with a globally unique 48-bit MAC address. The MAC addresses are used to specify both the destination and the source of each data packet. On the reception of a transmission,

5214-511: The same wireless channel, SSID, and other settings that have wirelessly connected, usually to the same access point. Each BSS is identified by a MAC address called the BSSID . The IEEE does not test equipment for compliance with their standards. The Wi-Fi Alliance was formed in 1999 to establish and enforce standards for interoperability and backward compatibility , and to promote wireless local-area-network technology. The Wi-Fi Alliance enforces

5293-468: The session type in use. Kiosk mode can be used for a number of different desktop or applications. Oracle has integrated a RDP client, VMware View client into the Sun Ray software that can be used in Kiosk mode to start a full screen Windows session. In this mode, no window manager or Unix desktop is started. The Windows environment can be any OS that supports RDP. In 2007, Sun and UK company Thruput integrated

5372-453: The smart card the procedure was almost identical, except the user must specify their username as well as password. In either case, if a session did not yet exist, a new one would be created the first time the user connects. Sun Ray clients are connected via an Ethernet network to a Sun Ray Server . Sun Ray Software (SRS) is available for the Solaris and Linux operating systems. Sun developed

5451-424: The state of the user's session being independent of the display. This enables another feature of the Sun Ray; portable sessions where a user can go from one Sun Ray to another and continue their work without closing any programs. With a smart card, all the user had to do was insert the card and they would be presented with their session. Reauthentication requirements depend on the mode of operation. For example, without

5530-445: The structure. Similarly, battery-powered routers may include a mobile broadband modem and a Wi-Fi access point. When subscribed to a cellular data carrier, they allow nearby Wi-Fi stations to access the Internet. Many smartphones have a built-in mobile hotspot capability of this sort, though carriers often disable the feature, or charge a separate fee to enable it. Standalone devices such as MiFi - and WiBro -branded devices provide

5609-413: The system. However, it is not necessary to implement network booting to achieve either of the above advantages - ordinary PCs (with the help of appropriate software) can be configured to download and reinstall their operating systems on (e.g.) a nightly basis, with extra work compared to using shared disk image that diskless nodes boot off. Modern diskless nodes can share the very same disk image, using

5688-756: The use of the Wi-Fi brand to technologies based on the IEEE 802.11 standards from the IEEE. Manufacturers with membership in the Wi-Fi Alliance, whose products pass the certification process, gain the right to mark those products with the Wi-Fi logo. Specifically, the certification process requires conformance to the IEEE 802.11 radio standards, the WPA and WPA2 security standards, and the EAP authentication standard. Certification may optionally include tests of IEEE 802.11 draft standards, interaction with cellular-phone technology in converged devices, and features relating to security set-up, multimedia, and power-saving. Not every Wi-Fi device

5767-418: The user, such as drawing a dialog box on the display or waiting for user input. A collective term encompassing both thin client computing, and its technological predecessor, text terminals (which are text-only), is centralized computing . Thin clients and text terminals can both require powerful central processing facilities in the servers, in order to perform all significant processing tasks for all of

5846-626: The world. The UK has planned a similar project across major cities of the country, with the project's first implementation in the London Borough of Camden . Officials in South Korea's capital Seoul were moving to provide free Internet access at more than 10,000 locations around the city, including outdoor public spaces, major streets, and densely populated residential areas. Seoul was planning to grant leases to KT, LG Telecom, and SK Telecom. The companies were supposed to invest $ 44 million in

5925-669: Was designed to have feature parity with a modern business PC in every way possible. Instead of a commercial operating system. the client ran a real-time operating system called "exec", which was originally developed in Sun Labs as part of an Ethernet-based security camera project codenamed NetCam . Less than 60 NeWTs were ever built and very few survived; one is in the collection of the Computer History Museum in Mountain View, California . In July 2013, reports circulated that Oracle

6004-470: Was ending the development of the Sun Ray and related products. Scott McNealy (long-time CEO of Sun) posted about this on Twitter. An official announcement was made on August 1, 2013, with the last order in February 2014. Support and hardware maintenance were available until 2017. In contrast to a thick client , the Sun Ray is only a networked display device, with applications running on a server elsewhere, and

6083-497: Was introduced as part of Sun Ray Software 5 (SRS5). This was later rebranded by Oracle as Oracle Virtual Desktop Client ; it was discontinued along with the Sun Ray product line in 2014. In commercial environments, Sun Rays were most commonly deployed as a thin client to access a Microsoft Windows desktop using the SRSS built-in RDP client uttsc . The desktop can be a Terminal Server session or

6162-788: Was selected because of its high level of integration, good performance, low cost, and availability. NeWT included 8  MiB of EDO DRAM and 4 MiB of NOR flash . The graphics controller used was the ATI Rage 128 because of its low power, 2D rendering performance, and low cost. It also included an ATI video encoder for TV-out (removed in the Sun Ray 1), a Philips Semiconductor SAA7114 video decoder/scaler, Crystal Semiconductor audio CODEC, Sun Microelectronics Ethernet controller, PCI USB host interface with 4 port hub, and I²C smart card interface. The motherboard and daughtercard were housed in an off-the-shelf commercial small form-factor PC case with internal +12/+5VDC auto ranging power supply. NeWT

6241-429: Was the first mass consumer product to offer Wi-Fi network connectivity, which was then branded by Apple as AirPort . This was in collaboration with the same group that helped create the standard: Vic Hayes , Bruce Tuch, Cees Links , Rich McGinn, and others from Lucent . In the year 2000, Radiata, a group of Australian scientists connected to the CSIRO, were the first to use the 802.11a standard on chips connected to

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