Glossary

Tech Terms | Abbreviations A–Z

U


UMTS   URI   URL   USB   USB Flash Drive   USB OTG   User   User ID   USSD


UMTS

(Abbr.:) Universal Mobile Telecommunications Systems. First global mobile radio standard. 3rd generation of the mobile communications age, 3G for short.

Uniform Resource Identifier (URI)

is a string of characters that unambiguously identifies a particular resource. To guarantee uniformity, all URIs follow a predefined set of syntax rules, but also maintain extensibility through a separately defined hierarchical naming scheme (e.g. http://).

Such identification enables interaction with representations of the resource over a network, typically the World Wide Web, using specific protocols. Schemes specifying a concrete syntax and associated protocols define each URI. The most common form of URI is the Uniform Resource Locator (URL), frequently referred to informally as a web address. More rarely seen in usage is the Uniform Resource Name (URN), which was designed to complement URLs by providing a mechanism for the identification of resources in particular namespaces.

This article is based on the article Uniform_Resource_Identifier from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

Uniform Resource Locator (URL)

colloquially termed a web address, is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it. A URL is a specific type of Uniform Resource Identifier (URI), although many people use the two terms interchangeably. URLs occur most commonly to reference web pages (http), but are also used for file transfer (ftp), email (mailto), database access (JDBC), and many other applications.

Most web browsers display the URL of a web page above the page in an address bar. A typical URL could have the form http://www.example.com/index.html, which indicates a protocol (http), a hostname (www.example.com), and a file name (index.html).

History
Uniform Resource Locators were defined in RFC 1738 in 1994 by Tim Berners-Lee, the inventor of the World Wide Web, and the URI working group of the Internet Engineering Task Force (IETF), as an outcome of collaboration started at the IETF Living Documents birds of a feather session in 1992.

The format combines the pre-existing system of domain names (created in 1985) with file path syntax, where slashes are used to separate directory and filenames. Conventions already existed where server names could be prefixed to complete file paths, preceded by a double slash (//).

Berners-Lee later expressed regret at the use of dots to separate the parts of the domain name within URIs, wishing he had used slashes throughout, and also said that, given the colon following the first component of a URI, the two slashes before the domain name were unnecessary.

This article is based on the article URL from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

USB

Universal Serial Bus (USB) is an industry standard that allows communication and delivery of power between many various types of electronics. It specifies the physical interface (the USB-C connector) and communication protocols for data transfer and power delivery to and from hosts, such as personal computers, peripheral devices, e.g. displays, keyboards, and mass storage devices, and intermediate hubs, which multiply the number of a host's ports. Prior versions of USB became commonplace on a wide range of devices, such as keyboards, mice, cameras, printers, scanners, flash drives, smartphones, game consoles, and power banks. USB was originally designed to standardize the connection of peripherals to computers, replacing various interfaces such as serial ports, parallel ports, game ports, and ADB ports and has evolved into a standard to replace virtually all common ports on computers, mobile devices, peripherals and power supplies. In the current standard the USB-C connector replaces the many various connectors for power (up to 240 W), displays (e.g. DisplayPort, HDMI), and many other uses, as well as all previous USB connectors.

As of 2023, USB consists of four generations of specifications: USB 1.x, USB 2.0, USB 3.x, and USB4. USB4 enhances the data transfer and power delivery functionality with

a connection-oriented, tunneling architecture designed to combine multiple protocols onto a single physical interface, so that the total speed and performance of the USB4 Fabric can be dynamically shared.

USB4 particularly supports the tunneling of the Thunderbolt 3 protocols, namely PCI Express(PCIe, load/store interface) and DisplayPort (display interface). USB4 also adds host-to-host interfaces.

Each specification subversion supports different maximum signaling rates from 1.5 and 12 Mbit/s total in USB 1.0 to 80 Gbit/s (in each direction) in USB4. USB also provides power to peripheral devices; the latest versions of the standard extend the power delivery limits for battery charging and devices requiring up to 240 watts (USB Power Delivery (USB-PD)). Over the years USB(-PD) has been adopted as the standard power supply and charging format for many mobile devices, such as mobile phones, reducing the need for proprietary chargers.

This article is based on the article USB from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

USB Flash Drive

A USB flash drive (also called a thumb drive in the US, or a memory stick in the UK & pen drive or pendrive in many countries) is a data storage device that includes flash memory with an integrated USB interface. It is typically removable, rewritable and much smaller than an optical disc. Most weigh less than 30 g (1 oz). Since first appearing on the market in late 2000, as with virtually all other computer memory devices, storage capacities have risen while prices have dropped. As of March 2016, flash drives with anywhere from 8 to 256 gigabytes (GB) were frequently sold, while 512 GB and 1 terabyte (TB) units were less frequent. As of 2018, 2 TB flash drives were the largest available in terms of storage capacity. Some allow up to 100,000 write/erase cycles, depending on the exact type of memory chip used, and are thought to physically last between 10 and 100 years under normal circumstances (shelf storage time).

Common uses of USB flash drives are for storage, supplementary back-ups, and transferring of computer files. Compared with floppy disks or CDs, they are smaller, faster, have significantly more capacity, and are more durable due to a lack of moving parts. Additionally, they are less vulnerable to electromagnetic interference than floppy disks, and are unharmed by surface scratches (unlike CDs). However, as with any flash storage, data loss from bit leaking due to prolonged lack of electrical power and the possibility of spontaneous controller failure due to poor manufacturing could make it unsuitable for long-term archiving of data. The ability to retain data is affected by the controller's firmware, internal data redundancy, and error correction algorithms.

This article is based on the article USB_flash_drive from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

USB OTG

USB On-The-Go (USB OTG or just OTG) is a specification first used in late 2001 that allows USB devices, such as tablets or smartphones, to also act as a host, allowing other USB devices, such as USB flash drives, digital cameras, mouse or keyboards, to be attached to them. Use of USB OTG allows devices to switch back and forth between the roles of host and device. For example, a smartphone may read from removable media as the host device, but present itself as a USB Mass Storage Device when connected to a host computer.

USB OTG introduces the concept of a device performing both Host and Peripheral roles – whenever two USB devices are connected and one of them is a USB OTG device, they establish a communication link. The device controlling the link is called the Host, while the other is called the Peripheral.

USB OTG defines two roles for devices: OTG A-device and OTG B-device, specifying which side supplies power to the link, and which initially is the host. The OTG A-device is a power supplier, and an OTG B-device is a power consumer. In the default link configuration, the A-device acts as a USB host with the B-device acting as a USB peripheral. The host and peripheral modes may be exchanged later by using Host Negotiation Protocol (HNP).

The wiring for the ID pin defines the initial role of each device.

This article is based on the article USB_On-The-Go from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

User

user is a person who utilizes a computer or network service

A user often has a user account and is identified to the system by a username (or user name). Other terms for username include login namescreenname (or screen name), account namenickname (or nick) and handle, which is derived from the identical citizens band radio term.

Some software products provide services to other systems and have no direct end users.

Terminology

Some usability professionals have expressed their dislike of the term “user” and have proposed changing it. Don Norman stated that “One of the horrible words we use is 'users'. I am on a crusade to get rid of the word 'users'. I would prefer to call them 'people'.”

The term “user” may imply lack of the technical expertise required to fully understand how computer systems and software products work. Power users use advanced features of programs, though they are not necessarily capable of computer programming and system administration.

This article is based on the article User_(computing) from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

User ID

Unix-like operating systems identify a user by a value called a user identifier, often abbreviated to user ID or UID. The UID, along with the group identifier (GID) and other access control criteria, is used to determine which system resources a user can access. The password file maps textual user names to UIDs. UIDs are stored in the inodes of the Unix file system, running processestar archives, and the now-obsolete Network Information Service. In POSIX-compliant environments, the shell command id gives the current user's UID, as well as more information such as the user name, primary user group and group identifier (GID).

This article is based on the article User_identifier from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

USSD

Unstructured Supplementary Service Data (USSD), sometimes referred to as “quick codes” or “feature codes”, is a communications protocol used by GSM cellular telephones to communicate with the mobile network operator's computers. USSD can be used for WAP browsing, prepaid callback service, mobile-money services, location-based content services, menu-based information services, and as part of configuring the phone on the network. The service does not require a messaging app, and does not incur charges.

USSD messages are up to 182 alphanumeric characters long. Unlike short message service (SMS) messages, USSD messages create a real-time connection during a USSD session. The connection remains open, allowing a two-way exchange of a sequence of data. This makes USSD faster than services that use SMS.

While GSM is being phased out in the 2020s with 2G and 3G technologies, USSD services can be supported over LTE, 5G, and IMS.

This article is based on the article Unstructured_Supplementary_Service_Data from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

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Keyword list: 3G, Computer, Database, Domain, FTP, Firmware, GSM, Glossary, HTML, HTTP, Hostname, IETF, IT, Internet, LTE, Link, Mobile Communications, Mobile Phones, Mouse, Network, Operator, POSIX, Peripherals, Power Supply, Prepaid, SMS, Server, Service, Services, Smartphone, Smartphones, Software, Storage, U, UMTS, URI, URL, USB, USSD, Unix, User, User ID, WWW, Web Page, Who, World Wide Web, how

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