Operating system - Wikipedia

For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware,[1][2] although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer – from cellular phones and video game consoles to web servers and supercomputers. Types of operating systems Single- and multi-tasking Single- and multi-user Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem.[6] A multi-user operating system extends the basic concept of multi-tasking with facilities that identify processes and resources, such as disk space, belonging to multiple users, and the system permits multiple users to interact with the system at the same time. Distributed Templated Embedded Real-time Library History Mainframes Microcomputers

Android - Wikipedia From Wikipedia, the free encyclopedia Jump to navigationJump to search Android may refer to: Technology Culture Film Music The Androids, an Australian rock band Songs Fictional characters Android 17, a character from the Dragon Ball franchiseAndroid 18, a character from the Dragon Ball franchise Other uses See also Ethernet - Wikipedia Ethernet /ˈiːθərnɛt/ is a family of computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN).[1] It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3,[2] and has since been refined to support higher bit rates and longer link distances. Over time, Ethernet has largely replaced competing wired LAN technologies such as Token Ring, FDDI and ARCNET. The original 10BASE5 Ethernet uses coaxial cable as a shared medium, while the newer Ethernet variants use twisted pair and fiber optic links in conjunction with hubs or switches. Over the course of its history, Ethernet data transfer rates have been increased from the original 2.94 megabits per second (Mbit/s)[3] to the latest 400 gigabits per second (Gbit/s). The Ethernet standards comprise several wiring and signaling variants of the OSI physical layer in use with Ethernet. History[edit] Standardization[edit] Evolution[edit] Notes[edit]

Wi-Fi - Wikipedia Wi-Fi or WiFi (/ˈwaɪfaɪ/[1]) is technology for radio wireless local area networking of devices based on the IEEE 802.11 standards. Wi‑Fi 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.[2] Depiction of a device sending information wirelessly to another device, both connected to the local network, in order to print a document Wi-Fi most commonly uses the 2.4 gigahertz (12 cm) UHF and 5.8 gigahertz (5 cm) SHF ISM radio bands, these bands are subdivided into multiple channels. Each channel can be time-shared by multiple networks. These wavelengths work best for line-of-sight. Anyone within range with a wireless network interface controller can attempt to access a network; because of this, Wi-Fi is more vulnerable to attack (called eavesdropping) than wired networks. History[edit] A 1985 ruling by the U.S. Etymology[edit] Interbrand also created the Wi-Fi logo. Uses[edit]

Bluetooth - Wikipedia Short-range wireless technology standard Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is limited to 2.5 milliwatts, giving it a very short range of up to 10 metres (33 ft). It employs UHF radio waves in the ISM bands, from 2.402 GHz to 2.48 GHz.[3] It is mainly used as an alternative to wired connections to exchange files between nearby portable devices and connect cell phones and music players with wireless headphones. Bluetooth is managed by the Bluetooth Special Interest Group (SIG), which has more than 35,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics. Etymology According to Bluetooth's official website, Bluetooth was only intended as a placeholder until marketing could come up with something really cool. The Bluetooth logo (ᚼ, Hagall) and Uses