1.
Wi-Fi
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Wi-Fi or WiFi is a technology for wireless local area networking with devices based on the IEEE802.11 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. Devices that can use Wi-Fi technology include personal computers, video-game consoles, smartphones, digital cameras, tablet computers, digital audio players, Wi-Fi compatible devices can connect to the Internet via a WLAN network and a wireless access point. Such an access point has a range of about 20 meters indoors, hotspot coverage can be as small as a single room with walls that block radio waves, or as large as many square kilometres achieved by using multiple overlapping access points. Wi-Fi most commonly uses the 2.4 gigahertz UHF and 5 gigahertz SHF ISM radio bands, having no physical connections, it is more vulnerable to attack than wired connections, such as Ethernet. In 1971, ALOHAnet connected the Hawaiian Islands with a UHF wireless packet network, ALOHAnet and the ALOHA protocol were early forerunners to Ethernet, and later the IEEE802.11 protocols, respectively. A1985 ruling by the U. S. Federal Communications Commission released the ISM band for unlicensed use and these frequency bands are the same ones used by equipment such as microwave ovens and are subject to interference. In 1991, NCR Corporation with AT&T Corporation invented the precursor to 802.11, the first wireless products were under the name WaveLAN. They are the credited with inventing Wi-Fi. In 1992 and 1996, CSIRO obtained patents for a method used in Wi-Fi to unsmear the signal. The first version of the 802.11 protocol was released in 1997 and this was updated in 1999 with 802. 11b to permit 11 Mbit/s link speeds, and this proved to be popular. In 1999, the Wi-Fi Alliance formed as an association to hold the Wi-Fi trademark under which most products are sold. Wi-Fi uses a number of patents held by many different organizations. In April 2009,14 technology companies agreed to pay CSIRO $1 billion for infringements on CSIRO patents and this led to Australia labeling Wi-Fi as an Australian invention, though this has been the subject of some controversy. In 2016, the local area network Test Bed was chosen as Australias 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 IEEE802. 11b Direct Sequence. Phil Belanger, a member of the Wi-Fi Alliance who presided over the selection of the name Wi-Fi, has stated that Interbrand invented Wi-Fi as a pun upon the word hi-fi. Interbrand also created the Wi-Fi logo, the yin-yang Wi-Fi logo indicates the certification of a product for interoperability
2.
Residential gateway
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In telecommunications networking, a residential gateway allows the connection of a local area network to a wide area network. The WAN can be a computer network, or the Internet. WAN connectivity may be provided through DSL, cable modem, a mobile phone network. The term residential gateway was originally used to distinguish the inexpensive networking devices designated for use in the home from devices used in corporate LAN environments. In recent years, however, the expensive residential gateways have gained many of the capabilities of corporate gateways. Many home LANs now are able to provide most of the functions of small corporate LANs, as a part of the carrier network, the home gateway supports remote control, detection and configuration. A modem by itself provides none of the functions of a router and it merely allows ATM or Ethernet or PPP traffic to be transmitted across telephone lines, cable wires, optical fibers, or wireless radio frequencies. On the receiving end is another modem that re-converts the transmission back into digital data packets. This allows network bridging using telephone, cable, optical, the modem also provides handshake protocols, so that the devices on each end of the connection are able to recognize each other. However, a modem generally provides few other network functions, a USB modem plugs into a single PC and allows a connection of that single PC to a WAN. If properly configured, the PC can also function as the router for a home LAN, an internal modem can be installed on a single PC, also allowing that single PC to connect to a WAN. Again, the PC can be configured to function as a router for a home LAN, a wireless access point can function in a similar fashion to a modem. It can allow a connection from a home LAN to a WAN. However, many modems now incorporate the features mentioned below and thus are appropriately described as residential gateways, may also have an internal modem, most commonly for DSL or Cable ISP. It may also provide functions such as Dynamic DNS. Most routers are self-contained components, using internally stored firmware and they are generally OS-independent, i. e. they can be accessed with any operating system. Wireless routers perform the functions as a router, but also allow connectivity for wireless devices with the LAN. Majority of the vulnerabilities were present in the web administration consoles of the routers, allowing unauthorised control either via default passwords, vendor backdoors, the Residential Gateway Home Gateway Initiative, a group of broadband providers proposing specifications for residential gateways The Residential Home Gateway on About. com
3.
Linksys
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Linksys is an American company selling data networking hardware products mainly to home users and small businesses. Its products include wired and wireless routers, Ethernet switches, VoIP equipment, wireless Internet video cameras, audio visual products, Linksys was founded in 1988 by the couple Victor and Janie Tsao, both Taiwanese immigrants to the United States. They were purchased by Cisco in 2003, and sold to Belkin and its products were branded as Linksys by Cisco when it was part of Cisco. Belkin has kept the Linksys brand and released new products under its name since acquiring it, Linksys products are sold to consumers off-the-shelf from consumer electronics stores, Internet retailers, and big-box retail stores such as supermarkets. Significant competitors in the home and small business networking market segment include D-Link, TP-Link, in 1988, the married couple Janie and Victor Tsao founded DEW International, later renamed Linksys, in the garage of their Irvine, California home. The founders were immigrants from Taiwan who held jobs as consultants specializing in pairing American technology vendors with manufacturers in Taiwan. The companys first products were printer sharers that connected multiple PCs to printers, from this it expanded into Ethernet hubs, network cards, and cords. By 1994, it had grown to 55 employees with revenues of $6.5 million. The company received a major boost in 1995, when Microsoft released Windows 95 with built-in networking functions that expanded the market for its products, Linksys established its first U. S. retail channels with Frys Electronics and Best Buy. In 1999, the announced the first Fast Ethernet PCMCIA Card for notebook PCs. In 2000, it introduced the first 8-port router with SNMP and QoS, by 2003, when the company was acquired by Cisco, it had 305 employees and revenues of more than $500 million. That was also the sum paid by Cisco for the company, Cisco expanded the companys product line, acquiring VoIP maker Sipura Technology in 2005 and selling its products under Linksys Voice System or later Linksys Business Series brands. In July 2008, Cisco acquired Seattle-based Pure Networks, a vendor of home networking-management software, Pure Networks had previously provided the tools and software infrastructure used to create the Linksys Easy Link Advisor. Cisco announced in January 2013 that it would sell its home networking division and Linksys to Belkin, Belkin pledged to continue support and honor warranties for existing Linksys products. The following is not a complete list of all security problems associated with Linksys products. The Linksys E1000, E1200, and E2400 routers are vulnerable to The Moon worm, various Sercomm manufactured, Linksys-branded modem-routers have root-level backdoors. BEFSR41 Ethernet router BEFSX41 VPN Endpoint Ethernet router WRT54G was notable for having firmware based on the Linux operating system, since version 5, flash memory is reduced from 4 MB to 2 MB, and VxWorks was used instead of Linux. The original Linux model with 4 MB is now available as WRT54GL, wRT54G2 router was a restyled version of the WRT54G containing the expected firewall features that protect from hackers that may try to access its network
4.
Cisco Systems
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Through its numerous acquired subsidiaries, such as OpenDNS, WebEx, and Jasper, Cisco specializes into specific tech markets, such as Internet of Things, domain security, and energy management. Cisco is the largest networking company in the world, the stock was added to the Dow Jones Industrial Average on June 8,2009, and is also included in the S&P500 Index, the Russell 1000 Index, NASDAQ-100 Index and the Russell 1000 Growth Stock Index. By the time the company went public in 1990, when it was listed on the NASDAQ, Cisco was the most valuable company in the world by 2000, with a more than $500 billion market capitalization. Despite founding Cisco in 1984, Bosack, along with Kirk Lougheed, continued to work at Stanford on Ciscos first product and it consisted of exact replicas of Stanfords Blue Box router and a stolen copy of the Universitys multiple-protocol router software. The software was written some years earlier at Stanford medical school by research engineer William Yeager. Bosack and Lougheed adapted it into what became the foundation for Cisco IOS, in 1987, Stanford licensed the router software and two computer boards to Cisco. In addition to Bosack, Lerner and Lougheed, Greg Satz, a programmer, and Richard Troiano, the companys first CEO was Bill Graves, who held the position from 1987 to 1988. In 1988, John Morgridge was appointed CEO, the name Cisco was derived from the city name San Francisco, which is why the companys engineers insisted on using the lower case cisco in its early years. The logo is intended to depict the two towers of the Golden Gate Bridge, on February 16,1990, Cisco Systems went public and was listed on the NASDAQ stock exchange. On August 28,1990, Lerner was fired, upon hearing the news, her husband Bosack resigned in protest. The couple walked away from Cisco with $170 million, 70% of which was committed to their own charity, although Cisco was not the first company to develop and sell dedicated network nodes, it was one of the first to sell commercially successful routers supporting multiple network protocols. Classical, CPU-based architecture of early Cisco devices coupled with flexibility of operating system IOS allowed for keeping up with evolving technology needs by means of frequent software upgrades, some popular models of that time managed to stay in production for almost a decade virtually unchanged—a rarity in high-tech industry. This philosophy dominated the companys product lines throughout the 1990s, in 1995, John Morgridge was succeeded by John Chambers. The phenomenal growth of the Internet in mid-to-late 1990s quickly changed the telecom landspe, as the Internet Protocol became widely adopted, the importance of multi-protocol routing declined. In late March 2000, at the height of the bubble, Cisco became the most valuable company in the world. In July 2014, with a cap of about US$129 billion. One of them, Juniper Networks, shipped their first product in 1999, Cisco answered the challenge with homegrown ASICs and fast processing cards for GSR routers and Catalyst 6500 switches. In 2004, Cisco also started migration to new high-end hardware CRS-1, as part of a massive rebranding campaign in 2006, Cisco Systems adopted the shortened name Cisco and created The Human Network advertising campaign
5.
Belkin
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Belkin International, Inc. is an American manufacturer of consumer electronics that specializes in connectivity devices. Belkin International is the parent company for Belkin, Linksys and Wemo branded products, Belkin was founded in April 18,1983 in Hawthorne, California, by Chet Pipkin. It has twice made Inc. magazines list of 500 fastest-growing privately held companies in the United States and it has major offices across the globe, including in the United Kingdom, the Netherlands, Hong Kong, and Australia. According to a PCWorld News article, Belkin officially completed the acquisition of Linksys on March 15,2013, Belkin was in the Inner City Top 100 list for six consecutive years, and the Los Angeles Business Journal’s “Fastest Growing Private Companies” list for five. Belkin was awarded iLounges Accessory Maker of the Year Award for 2007, Belkin stepped in after the team formerly known as Rabobank lost their headline sponsor. Belkin is involved in the local Compton community through the ASAP program with the LASD, Belkin supports Susan G. Komen for the Cure to fight breast cancer through its pink ribbon iPod cases that have helped raise $350,000 for the organization. In 2007, Belkin made a donation to the One Laptop per Child initiative. In 2003, Belkin released a home use wireless router which would occasionally replace users HTTP requests with an advertisement for Belkins filtering software, Belkin received some intense criticism for this from technically literate customers and others who described it as a man-in-the-middle attack or a form of session hijacking. In early 2009, a Belkin online sales representative was discovered paying Amazon. com, Newegg, Belkins President, Mark Reynoso, responded to criticism, saying that the company does not engage in unethical practices, noting however that one of our employees may have been responsible
6.
Local area network
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By contrast, a wide area network, not only covers a larger geographic distance, but also generally involves leased telecommunication circuits or Internet links. An even greater contrast is the Internet, which is a system of globally connected business, Ethernet and Wi-Fi are the two most common transmission technologies in use for local area networks. Historical technologies include ARCNET, Token ring, and AppleTalk, the increasing demand and use of computers in universities and research labs in the late 1960s generated the need to provide high-speed interconnections between computer systems. A1970 report from the Lawrence Radiation Laboratory detailing the growth of their Octopus network gave an indication of the situation. A number of experimental and early commercial LAN technologies were developed in the 1970s, Cambridge Ring was developed at Cambridge University starting in 1974. Ethernet was developed at Xerox PARC in 1973–1975, and filed as U. S, in 1976, after the system was deployed at PARC, Robert Metcalfe and David Boggs published a seminal paper, Ethernet, Distributed Packet-Switching for Local Computer Networks. ARCNET was developed by Datapoint Corporation in 1976 and announced in 1977 and it had the first commercial installation in December 1977 at Chase Manhattan Bank in New York. The initial driving force for networking was generally to share storage and printers, there was much enthusiasm for the concept and for several years, from about 1983 onward, computer industry pundits would regularly declare the coming year to be, “The year of the LAN”. In practice, the concept was marred by proliferation of incompatible physical layer and network protocol implementations, typically, each vendor would have its own type of network card, cabling, protocol, and network operating system. Netware dominated the personal computer LAN business from early after its introduction in 1983 until the mid-1990s when Microsoft introduced Windows NT Advanced Server, of the competitors to NetWare, only Banyan Vines had comparable technical strengths, but Banyan never gained a secure base. During the same period, Unix workstations were using TCP/IP networking, early LAN cabling had generally been based on various grades of coaxial cable. This led to the development of 10BASE-T and structured cabling which is still the basis of most commercial LANs today, while fiber-optic cabling is common for links between switches, use of fiber to the desktop is rare. Many LANs use wireless technologies that are built into Smartphones, tablet computers, in a wireless local area network, users may move unrestricted in the coverage area. Wireless networks have become popular in residences and small businesses, because of their ease of installation, guests are often offered Internet access via a hotspot service. Network topology describes the layout of interconnections between devices and network segments, at the data link layer and physical layer, a wide variety of LAN topologies have been used, including ring, bus, mesh and star. At the higher layers, NetBEUI, IPX/SPX, AppleTalk and others were once common, simple LANs generally consist of cabling and one or more switches. A switch can be connected to a router, cable modem, a LAN can include a wide variety of other network devices such as firewalls, load balancers, and network intrusion detection. LANs can maintain connections with other LANs via leased lines, leased services, depending on how the connections are established and secured, and the distance involved, such linked LANs may also be classified as a metropolitan area network or a wide area network
7.
Home network
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A home network or home area network is a type of computer network that facilitates communication among devices within the close vicinity of a home. Establishing this kind of network is necessary when there is need to distribute residential Internet access to all internet capable devices in the home. Due to the effect of IPv4 address exhaustion, most Internet service providers provide only a single WAN-facing IP address for each residential subscription, in homes these usually come in the form of a DSL modem or cable modem. A router manages network layer connectivity between a WAN and the HAN, most home networks feature a particular class of small, passively cooled, table-top device with an integrated wireless access point and 4 port Ethernet switch. These devices aim to make the installation, configuration, and management of a network as automated, user friendly. A network switch is used to allow devices on the network to talk to one another via Ethernet. While the needs of most home networks are satisfied with the built-in wireless and/or switching capabilities of their router, for example, When the routers switching capacity is exceeded. Most home routers expose only 4 to 6 Ethernet ports, most home networks rely on one wireless router combination device to fill this role. A home automation controller enables low-power wireless communications with simple, non-data-intensive devices such as light bulbs, a network bridge connecting two network interfaces to each other, often in order to grant a wired-only device, e. g. Xbox, access to a wireless network medium. Home networks can use either wired or wireless technologies to connect endpoints, wireless is the predominant option in homes due to the ease of installation, lack of unsightly cables, and network performance characteristics sufficient for residential activities. One of the most common ways of creating a network is by using wireless radio signal technology. Most wireless-capable residential devices operate at a frequency of 2.4 GHz under 802. 11b and 802. 11g or 5 GHz under 802. 11a, some home networking devices operate in both radio-band signals and fall within the 802. 11n or 802. 11ac standards. Wi-Fi is a marketing and compliance certification for IEEE802.11 technologies, the Wi-Fi Alliance has tested compliant products, and certifies them for interoperability. Low power, close range communication based on IEEE802.15 standards has a presence in homes. Bluetooth continues to be the technology of choice for most wireless accessories such as keyboards, mice, headsets and these connections are often established in a transient, ad-hoc manner and are not thought of as permanent residents of a home network. A low-rate version of the original WPAN protocol was used as the basis of ZigBee, ZigBee utilizes mesh networking to overcome the distance limitations associated with traditional WPAN in order to establish a single network of addressable devices spread across the entire building. Z-Wave is a standard also built on 802.15.4. Most wired network infrastructures found in homes utilize Category 5 or Category 6 twisted pair cabling with RJ45 compatible terminations and this medium provides physical connectivity between the Ethernet interfaces present on a large number of residential IP-aware devices
8.
Wide area network
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A wide area network is a telecommunications network or computer network that extends over a large geographical distance. Wide area networks are often established with leased telecommunication circuits, business, education and government entities use wide area networks to relay data among staff, students, clients, buyers, and suppliers from various locations across the world. In essence, this mode of telecommunication allows a business to carry out its daily function regardless of location. The Internet may be considered a WAN, the textbook definition of a WAN is a computer network spanning regions, countries, or even the world. WANs do not just necessarily connect physically disparate LANs, a CAN, for example, may have a localised backbone of a WAN technology, which connects different LANs within a campus. This could be to facilitate higher bandwidth applications, or provide better functionality for users in the CAN, WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations. Many WANs are built for one particular organization and are private, others, built by Internet service providers, provide connections from an organizations LAN to the Internet. WANs are often built using leased lines, at each end of the leased line, a router connects the LAN on one side with a second router within the LAN on the other. Leased lines can be very expensive, instead of using leased lines, WANs can also be built using less costly circuit switching or packet switching methods. Network protocols including TCP/IP deliver transport and addressing functions, protocols including Packet over SONET/SDH, Multiprotocol Label Switching, Asynchronous Transfer Mode and Frame Relay are often used by service providers to deliver the links that are used in WANs. X.25 was an important early WAN protocol, and is considered to be the grandfather of Frame Relay as many of the underlying protocols. Academic research into wide area networks can be broken down into three areas, mathematical models, network emulation and network simulation, performance improvements are sometimes delivered via wide area file services or WAN optimization. Many technologies are available for wide area network links, examples include circuit switched telephone lines, radio wave transmission, and optic fiber. New developments in technologies have successively increased transmission rates,1960, a 110 bit/s line was normal on the edge of the WAN, while core links of 56 kbit/s to 64 kbit/s were considered fast. AT&T plans to start conducting trials in the year 2017 for businesses to use 400 Gigabit Ethernet, researchers Robert Maher, Alex Alvarado, Domaniç Lavery & Polina Bayvel of University College London were able to increase networking speeds to 1.125 Terabits per second. Christos Santis, graduate student Scott Steger, Amnon Yariv, Martin, ATM Cable modem Dial-up DSL Frame relay ISDN Leased line SONET X.25 SD-WAN Cisco - Introduction to WAN Technologies
9.
Internet
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The Internet is the global system of interconnected computer networks that use the Internet protocol suite to link devices worldwide. The origins of the Internet date back to research commissioned by the United States federal government in the 1960s to build robust, the primary precursor network, the ARPANET, initially served as a backbone for interconnection of regional academic and military networks in the 1980s. Although the Internet was widely used by academia since the 1980s, Internet use grew rapidly in the West from the mid-1990s and from the late 1990s in the developing world. In the two decades since then, Internet use has grown 100-times, measured for the period of one year, newspaper, book, and other print publishing are adapting to website technology, or are reshaped into blogging, web feeds and online news aggregators. The entertainment industry was initially the fastest growing segment on the Internet, the Internet has enabled and accelerated new forms of personal interactions through instant messaging, Internet forums, and social networking. Business-to-business and financial services on the Internet affect supply chains across entire industries, the Internet has no centralized governance in either technological implementation or policies for access and usage, each constituent network sets its own policies. The term Internet, when used to refer to the global system of interconnected Internet Protocol networks, is a proper noun. In common use and the media, it is not capitalized. Some guides specify that the word should be capitalized when used as a noun, the Internet is also often referred to as the Net, as a short form of network. Historically, as early as 1849, the word internetted was used uncapitalized as an adjective, the designers of early computer networks used internet both as a noun and as a verb in shorthand form of internetwork or internetworking, meaning interconnecting computer networks. The terms Internet and World Wide Web are often used interchangeably in everyday speech, however, the World Wide Web or the Web is only one of a large number of Internet services. The Web is a collection of interconnected documents and other web resources, linked by hyperlinks, the term Interweb is a portmanteau of Internet and World Wide Web typically used sarcastically to parody a technically unsavvy user. The ARPANET project led to the development of protocols for internetworking, the third site was the Culler-Fried Interactive Mathematics Center at the University of California, Santa Barbara, followed by the University of Utah Graphics Department. In an early sign of growth, fifteen sites were connected to the young ARPANET by the end of 1971. These early years were documented in the 1972 film Computer Networks, early international collaborations on the ARPANET were rare. European developers were concerned with developing the X.25 networks, in December 1974, RFC675, by Vinton Cerf, Yogen Dalal, and Carl Sunshine, used the term internet as a shorthand for internetworking and later RFCs repeated this use. Access to the ARPANET was expanded in 1981 when the National Science Foundation funded the Computer Science Network, in 1982, the Internet Protocol Suite was standardized, which permitted worldwide proliferation of interconnected networks.5 Mbit/s and 45 Mbit/s. Commercial Internet service providers emerged in the late 1980s and early 1990s, the ARPANET was decommissioned in 1990
10.
MIPS architecture
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MIPS is a reduced instruction set computer instruction set architecture developed by MIPS Technologies. The early MIPS architectures were 32-bit, with 64-bit versions added later, multiple revisions of the MIPS instruction set exist, including MIPS I, MIPS II, MIPS III, MIPS IV, MIPS V, MIPS32, and MIPS64. The current revisions are MIPS32 and MIPS64, MIPS32 and MIPS64 define a control register set as well as the instruction set. Computer architecture courses in universities and technical schools often study the MIPS architecture, the architecture greatly influenced later RISC architectures such as Alpha. It used to be popular in supercomputers but all systems have dropped off the TOP500 list. Until late 2006, they were used in many of SGIs computer products. MIPS implementations were also used by Digital Equipment Corporation, NEC, Pyramid Technology, Siemens Nixdorf, in the mid to late 1990s, it was estimated that one in three RISC microprocessors produced was a MIPS implementation. Windows NT supported MIPS until the release of Windows NT4.0 SP3 in 1997, MIPS is a modular architecture supporting up to four coprocessors. In MIPS terminology, COP0 is the System Control Coprocessor, COP1 is an optional FPU, for example, in the original Playstation game console, COP0 is the System Control Coprocessor and COP2 is Geometry Transformation Engine. In the Playstation 2 game console, COP0 is a Toshiba R5900 chip, COP1 is a FPU, MIPS is a load-store architecture, meaning it only performs arithmetic and logic operations between CPU registers, requiring load/store instructions to access memory. Processors based upon the MIPS instruction set have been in production since 1988, over time several enhancements of the instruction set were made. The different revisions which have introduced are MIPS I, MIPS II, MIPS III, MIPS IV. Each revision is a superset of its predecessors, when MIPS Technologies was spun out of Silicon Graphics again in 1998, they refocused on the embedded market. At that time, this property was found to be a problem, and the architecture definition was changed to define a 32-bit MIPS32. Introduced in 1985 with the R2000, introduced in 1990 with the R6000. Introduced in 1992 in the R4000 and it adds 64-bit registers and integer instructions and a floating point square root instruction. MIPS IV is the version of the architecture. It is a superset of MIPS III and is compatible with all existing versions of MIPS, the first implementation of MIPS IV was the R8000, which was introduced in 1994
11.
Central processing unit
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The computer industry has used the term central processing unit at least since the early 1960s. The form, design and implementation of CPUs have changed over the course of their history, most modern CPUs are microprocessors, meaning they are contained on a single integrated circuit chip. An IC that contains a CPU may also contain memory, peripheral interfaces, some computers employ a multi-core processor, which is a single chip containing two or more CPUs called cores, in that context, one can speak of such single chips as sockets. Array processors or vector processors have multiple processors that operate in parallel, there also exists the concept of virtual CPUs which are an abstraction of dynamical aggregated computational resources. Early computers such as the ENIAC had to be rewired to perform different tasks. Since the term CPU is generally defined as a device for software execution, the idea of a stored-program computer was already present in the design of J. Presper Eckert and John William Mauchlys ENIAC, but was initially omitted so that it could be finished sooner. On June 30,1945, before ENIAC was made, mathematician John von Neumann distributed the paper entitled First Draft of a Report on the EDVAC and it was the outline of a stored-program computer that would eventually be completed in August 1949. EDVAC was designed to perform a number of instructions of various types. Significantly, the programs written for EDVAC were to be stored in high-speed computer memory rather than specified by the wiring of the computer. This overcame a severe limitation of ENIAC, which was the considerable time, with von Neumanns design, the program that EDVAC ran could be changed simply by changing the contents of the memory. Early CPUs were custom designs used as part of a larger, however, this method of designing custom CPUs for a particular application has largely given way to the development of multi-purpose processors produced in large quantities. This standardization began in the era of discrete transistor mainframes and minicomputers and has accelerated with the popularization of the integrated circuit. The IC has allowed increasingly complex CPUs to be designed and manufactured to tolerances on the order of nanometers, both the miniaturization and standardization of CPUs have increased the presence of digital devices in modern life far beyond the limited application of dedicated computing machines. Modern microprocessors appear in electronic devices ranging from automobiles to cellphones, the so-called Harvard architecture of the Harvard Mark I, which was completed before EDVAC, also utilized a stored-program design using punched paper tape rather than electronic memory. Relays and vacuum tubes were used as switching elements, a useful computer requires thousands or tens of thousands of switching devices. The overall speed of a system is dependent on the speed of the switches, tube computers like EDVAC tended to average eight hours between failures, whereas relay computers like the Harvard Mark I failed very rarely. In the end, tube-based CPUs became dominant because the significant speed advantages afforded generally outweighed the reliability problems, most of these early synchronous CPUs ran at low clock rates compared to modern microelectronic designs. Clock signal frequencies ranging from 100 kHz to 4 MHz were very common at this time, the design complexity of CPUs increased as various technologies facilitated building smaller and more reliable electronic devices
12.
Fast Ethernet
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In computer networking, Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100 Mbit/s. Of the Fast Ethernet standards, 100BASE-TX is by far the most common, Fast Ethernet was introduced in 1995 as the IEEE802. 3u standard and remained the fastest version of Ethernet for three years before the introduction of Gigabit Ethernet. The acronym GE/FE is sometimes used for supporting both standards. Fast Ethernet is an extension of the 10-megabit Ethernet standard and it runs on UTP data or optical fiber cable in a star wired bus topology, similar to 10BASE-T where all cables are attached to a hub. Fast Ethernet devices are backward compatible with existing 10BASE-T systems. Fast Ethernet is sometimes referred to as 100BASE-X, where X is a placeholder for the FX, the standard specifies the use of CSMA/CD for media access control. A full-duplex mode is also specified and in all modern networks use Ethernet switches. The 100 in the type designation refers to the transmission speed of 100 Mbit/s. The letter following the dash refers to the medium that carries the signal. A Fast Ethernet adapter can be divided into a media access controller, which deals with the higher-level issues of medium availability. The MAC may be linked to the PHY by a four-bit 25 MHz synchronous parallel interface known as a media-independent interface, in rare cases the MII may be an external connection but is usually a connection between ICs in a network adapter or even within a single IC. The specs are based on the assumption that the interface between MAC and PHY will be a MII but they do not require it. Repeaters may use the MII to connect to multiple PHYs for their different interfaces, the MII fixes the theoretical maximum data bit rate for all versions of Fast Ethernet to 100 Mbit/s. 100BASE-T is any of several Fast Ethernet standards for twisted pair cables, including, 100BASE-TX, 100BASE-T4, the segment length for a 100BASE-T cable is limited to 100 metres. All are or were standards under IEEE802.3, almost all 100BASE-T installations are 100BASE-TX. In the early days of Fast Ethernet, much vendor advertising centered on claims by competing standards that said vendors standards will work better with existing cables than other standards. Thus most networks had to be rewired for 100 Megabit speed whether or not there had supposedly been CAT3 or CAT5 cable runs, 100BASE-TX is the predominant form of Fast Ethernet, and runs over two wire-pairs inside a category 5 or above cable. Like 10BASE-T, the pairs in a standard connection are terminated on pins 1,2,3 and 6
13.
IEEE 802.11
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They are created and maintained by the Institute of Electrical and Electronics Engineers LAN/MAN Standards Committee. The base version of the standard was released in 1997, and has had subsequent amendments, the standard and amendments provide the basis for wireless network products using the Wi-Fi brand. As a result, in the marketplace, each tends to become its own standard. The 802.11 family consists of a series of half-duplex over-the-air modulation techniques that use the basic protocol. 802. 11-1997 was the first wireless networking standard in the family, but 802. 11b was the first widely accepted one, followed by 802. 11a,802. 11g,802. 11n, and 802. 11ac. Other standards in the family are service amendments that are used to extend the current scope of the existing standard, which may also include corrections to a previous specification. 802. 11b and 802. 11g use the 2.4 GHz ISM band, operating in the United States under Part 15 of the U. S. Federal Communications Commission Rules and Regulations. Because of this choice of band,802. 11b and g equipment may occasionally suffer interference from microwave ovens, cordless telephones. Better or worse performance with higher or lower frequencies may be realized,802. 11n can use either the 2.4 GHz or the 5 GHz band,802. 11ac uses only the 5 GHz band. The segment of the frequency spectrum used by 802.11 varies between countries. In the US,802. 11a and 802. 11g devices may be operated without a license, as allowed in Part 15 of the FCC Rules and Regulations. Frequencies used by one through six of 802. 11b and 802. 11g fall within the 2.4 GHz amateur radio band. Licensed amateur radio operators may operate 802. 11b/g devices under Part 97 of the FCC Rules and Regulations, allowing increased power output but not commercial content or encryption. 802.11 technology has its origins in a 1985 ruling by the U. S. Federal Communications Commission that released the ISM band for unlicensed use, in 1991 NCR Corporation/AT&T invented a precursor to 802.11 in Nieuwegein, the Netherlands. The inventors initially intended to use the technology for cashier systems, the first wireless products were brought to the market under the name WaveLAN with raw data rates of 1 Mbit/s and 2 Mbit/s. Vic Hayes, who held the chair of IEEE802.11 for 10 years, in 1999, the Wi-Fi Alliance was formed as a trade association to hold the Wi-Fi trademark under which most products are sold. The original version of the standard IEEE802.11 was released in 1997 and clarified in 1999 and it specified two net bit rates of 1 or 2 megabits per second, plus forward error correction code. The latter two radio technologies used microwave transmission over the Industrial Scientific Medical frequency band at 2.4 GHz, some earlier WLAN technologies used lower frequencies, such as the U. S.900 MHz ISM band
14.
Network switch
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A network switch is a computer networking device that connects devices together on a computer network by using packet switching to receive, process, and forward data to the destination device. Unlike less advanced network hubs, a network switch forwards data only to one or multiple devices that need to receive it, a network switch is a multiport network bridge that uses hardware addresses to process and forward data at the data link layer of the OSI model. Switches for Ethernet are the most common form and the first Ethernet switch was introduced by Kalpana in 1990, Switches also exist for other types of networks including Fibre Channel, Asynchronous Transfer Mode, and InfiniBand. A switch is a device in a network that electrically and logically connects together other devices. Multiple data cables are plugged into a switch to enable communication between different networked devices, Switches manage the flow of data across a network by transmitting a received network packet only to the one or more devices for which the packet is intended. Each networked device connected to a switch can be identified by its network address and this maximizes the security and efficiency of the network. Because broadcasts are still being forwarded to all connected devices, the newly formed network segment continues to be a broadcast domain, an Ethernet switch operates at the data link layer of the OSI model to create a separate collision domain for each switch port. In full duplex mode, each switch port can simultaneously transmit and receive, in the case of using a repeater hub, only a single transmission could take place at a time for all ports combined, so they would all share the bandwidth and run in half duplex. Necessary arbitration would result in collisions, requiring retransmissions. The network switch plays an role in most modern Ethernet local area networks. Mid-to-large sized LANs contain a number of linked managed switches, in most of these cases, the end-user device contains a router and components that interface to the particular physical broadband technology. User devices may include a telephone interface for Voice over IP protocol. Segmentation involves the use of a bridge or a switch to split a larger collision domain into smaller ones in order to reduce collision probability, in the extreme case, each device is located on a dedicated switch port. In contrast to an Ethernet hub, there is a separate collision domain on each of the switch ports and this allows computers to have dedicated bandwidth on point-to-point connections to the network and also to run in full-duplex without collisions. Full-duplex mode has one transmitter and one receiver per collision domain. Switches may operate at one or more layers of the OSI model, including the data link, a device that operates simultaneously at more than one of these layers is known as a multilayer switch. In switches intended for use, built-in or modular interfaces make it possible to connect different types of networks, including Ethernet, Fibre Channel, RapidIO, ATM. This connectivity can be at any of the layers mentioned, while the layer-2 functionality is adequate for bandwidth-shifting within one technology, interconnecting technologies such as Ethernet and token ring is performed easier at layer 3 or via routing
15.
TNC connector
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The TNC connector is a threaded version of the BNC connector. The connector has a 50 Ω impedance and operates best in the 0–11 GHz frequency spectrum and it has better performance than the BNC connector at microwave frequencies. Invented in the late 1950s and named after Paul Neill of Bell Labs and Carl Concelman of Amphenol, the abbreviation TNC is sometimes given as standing for Threaded Navy Connector. Reverse-polarity TNC is a variation of the TNC specification which reverses the polarity of the interface and this is usually achieved by incorporating the female contacts normally found in jacks into the plug, and the male contacts normally found in plugs into the jack. The FCC considered that the RP-TNC was acceptable in preventing consumers changing the antenna, as of 2013, leading manufacturers are still using RP-TNC connectors on their Wi-Fi equipment. Most TNC connectors are 50-ohm type even when used with coaxial cable of other impedances and these can be recognized by a reduced amount of dielectric in the mating ends. They are intermatable with standard types, RF connector SMA connector, SMB connector, SMC connector BNC connector, N connector Optical fiber connector
16.
Linux kernel
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The Linux kernel is a monolithic Unix-like computer operating system kernel. The Android operating system for computers, smartphones and smartwatches is also based atop the Linux kernel. While the adoption on desktop computers is low, Linux-based operating systems dominate nearly every segment of computing. As of November 2016, all but two of the worlds 500 most powerful supercomputers run Linux, Linux rapidly attracted developers and users who adopted it as the kernel for other free software projects, notably the GNU Operating System. The Linux kernel has received contributions from nearly 12,000 programmers from more than 1,200 companies, the Linux kernel API, the application programming interface through which user programs interact with the kernel, is meant to be very stable and to not break userspace programs. As part of the functionality, device drivers control the hardware. However, the interface between the kernel and loadable kernel modules, unlike in many other kernels and operating systems, is not meant to be stable by design. The Linux kernel, developed by contributors worldwide, is a prominent example of free, day-to-day development discussions take place on the Linux kernel mailing list. The Linux kernel is released under the GNU General Public License version 2, in April 1991, Linus Torvalds, at the time a 21-year-old computer science student at the University of Helsinki, Finland, started working on some simple ideas for an operating system. He started with a task switcher in Intel 80386 assembly language, on 25 August 1991, Torvalds posted the following to comp. os. minix, a newsgroup on Usenet, Im doing a operating system for 386 AT clones. This has been brewing since April, and is starting to get ready, id like any feedback on things people like/dislike in minix, as my OS resembles it somewhat. Ive currently ported bash and gcc, and things seem to work and this implies that Ill get something practical within a few months Yes - its free of any minix code, and it has a multi-threaded fs. It is NOT portable, and it never will support anything other than AT-harddisks, as thats all I have. Its mostly in C, but most people wouldnt call what I write C and it uses every conceivable feature of the 386 I could find, as it was also a project to teach me about the 386. As already mentioned, it uses a MMU, for both paging and segmentation and its the segmentation that makes it REALLY386 dependent. Some of my C-files are almost as much assembler as C, unlike minix, I also happen to LIKE interrupts, so interrupts are handled without trying to hide the reason behind them. After that, many people contributed code to the project, early on, the MINIX community contributed code and ideas to the Linux kernel. At the time, the GNU Project had created many of the components required for an operating system
17.
Firmware
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In electronic systems and computing, firmware is a type of software that provides control, monitoring and data manipulation of engineered products and systems. Typical examples of devices containing firmware are embedded systems, computers, computer peripherals, mobile phones, the firmware contained in these devices provides the low-level control program for the device. As of 2013, most firmware can be updated, firmware is held in non-volatile memory devices such as ROM, EPROM, or flash memory. Changing the firmware of a device may rarely or never be done during its lifetime, some firmware memory devices are permanently installed, common reasons for updating firmware include fixing bugs or adding features to the device. This may require ROM integrated circuits to be replaced, or flash memory to be reprogrammed through a special procedure. Firmware such as the ROM BIOS of a computer may contain only elementary basic functions of a device. Firmware such as the program of a system may be the only program that will run on the system. Before integrated circuits, other firmware devices included a discrete semiconductor diode matrix, ascher Opler coined the term firmware in a 1967 Datamation article. As originally used, firmware contrasted with hardware and software and it was not composed of CPU machine instructions, but of lower-level microcode involved in the implementation of machine instructions. It existed on the boundary between hardware and software, thus the name firmware, in some respects, the various firmware components are as important as the operating system in a working computer. However, unlike most modern operating systems, firmware rarely has an automatic mechanism of updating itself to fix any functionality issues detected after shipping the unit. The BIOS may be updated by a user, using a small utility program. In contrast, firmware in storage devices rarely gets updated, even when flash storage is used for the firmware, there are no standardized mechanisms for detecting or updating firmware versions, most computer peripherals are themselves special-purpose computers. Devices such as printers, scanners, cameras and USB flash drives have internally stored firmware, some low-cost peripherals no longer contain non-volatile memory for firmware, and instead rely on the host system to transfer the device control program from a disk file or CD. As of 2010 most portable music players support firmware upgrades, some companies use firmware updates to add new playable file formats, iriver added Vorbis playback support this way, for instance. Other features that may change with firmware updates include the GUI or even the battery life, since 1996 most automobiles have employed an on-board computer and various sensors to detect mechanical problems. As of 2010, modern vehicles also employ computer-controlled ABS systems, the driver can also get in-dash information while driving in this manner, such as real-time fuel economy and tire pressure readings. Local dealers can update most vehicle firmware, sometimes, third parties create an unofficial new or modified version of firmware in order to provide new features or to unlock hidden functionality, this is referred to as custom firmware
18.
Random-access memory
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Random-access memory is a form of computer data storage which stores frequently used program instructions to increase the general speed of a system. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the location of data inside the memory. RAM contains multiplexing and demultiplexing circuitry, to connect the lines to the addressed storage for reading or writing the entry. Usually more than one bit of storage is accessed by the same address, in todays technology, random-access memory takes the form of integrated circuits. RAM is normally associated with types of memory, where stored information is lost if power is removed. Other types of non-volatile memories exist that allow access for read operations. These include most types of ROM and a type of memory called NOR-Flash. Integrated-circuit RAM chips came into the market in the early 1970s, with the first commercially available DRAM chip, early computers used relays, mechanical counters or delay lines for main memory functions. Ultrasonic delay lines could only reproduce data in the order it was written, drum memory could be expanded at relatively low cost but efficient retrieval of memory items required knowledge of the physical layout of the drum to optimize speed. Latches built out of vacuum tube triodes, and later, out of transistors, were used for smaller and faster memories such as registers. Such registers were relatively large and too costly to use for large amounts of data, the first practical form of random-access memory was the Williams tube starting in 1947. It stored data as electrically charged spots on the face of a cathode ray tube, since the electron beam of the CRT could read and write the spots on the tube in any order, memory was random access. The capacity of the Williams tube was a few hundred to around a thousand bits, but it was smaller, faster. In fact, rather than the Williams tube memory being designed for the SSEM, magnetic-core memory was invented in 1947 and developed up until the mid-1970s. It became a form of random-access memory, relying on an array of magnetized rings. By changing the sense of each rings magnetization, data could be stored with one bit stored per ring, since every ring had a combination of address wires to select and read or write it, access to any memory location in any sequence was possible. Magnetic core memory was the form of memory system until displaced by solid-state memory in integrated circuits. Data was stored in the capacitance of each transistor, and had to be periodically refreshed every few milliseconds before the charge could leak away
19.
Flash memory
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Flash memory is electronic non-volatile computer storage medium that can be electrically erased and reprogrammed. Toshiba developed flash memory from EEPROM in the early 1980s and introduced it to the market in 1984, the two main types of flash memory are named after the NAND and NOR logic gates. The individual flash memory cells exhibit internal characteristics similar to those of the corresponding gates, where EPROMs had to be completely erased before being rewritten, NAND-type flash memory may be written and read in blocks which are generally much smaller than the entire device. NOR-type flash allows a machine word to be written—to an erased location—or read independently. The NAND type operates primarily in memory cards, USB flash drives, solid-state drives, NAND or NOR flash memory is also often used to store configuration data in numerous digital products, a task previously made possible by EEPROM or battery-powered static RAM. One key disadvantage of flash memory is that it can endure a relatively small number of write cycles in a specific block. In addition to being non-volatile, flash memory offers fast read access times, although flash memory is technically a type of EEPROM, the term EEPROM is generally used to refer specifically to non-flash EEPROM which is erasable in small blocks, typically bytes. Because erase cycles are slow, the block sizes used in flash memory erasing give it a significant speed advantage over non-flash EEPROM when writing large amounts of data. As of 2013, flash memory costs much less than byte-programmable EEPROM and had become the dominant memory type wherever a system required a significant amount of non-volatile solid-state storage, Flash memory was invented by Fujio Masuoka while working for Toshiba circa 1980. According to Toshiba, the flash was suggested by Masuokas colleague, Shōji Ariizumi. Masuoka and colleagues presented the invention at the IEEE1984 International Electron Devices Meeting held in San Francisco, Intel Corporation saw the massive potential of the invention and introduced the first commercial NOR type flash chip in 1988. NOR-based flash has long erase and write times, but provides full address and data buses, allowing random access to any memory location. This makes it a replacement for older read-only memory chips. Its endurance may be from as little as 100 erase cycles for a flash memory, to a more typical 10,000 or 100,000 erase cycles. NOR-based flash was the basis of early flash-based removable media, CompactFlash was originally based on it, however, the I/O interface of NAND flash does not provide a random-access external address bus. Rather, data must be read on a basis, with typical block sizes of hundreds to thousands of bits. This makes NAND flash unsuitable as a replacement for program ROM. In this regard, NAND flash is similar to other data storage devices, such as hard disks and optical media
20.
Serial code
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A serial code is a unique identifier assigned incrementally or sequentially to an item. It is also called a number, although it may be a character string that includes letters and other typographical symbols. Serial numbers identify otherwise identical individual units with many, obvious uses, Serial numbers are a deterrent against theft and counterfeit products, as they can be recorded, and stolen or otherwise irregular goods can be identified. Banknotes and other documents of value bear serial numbers to assist in preventing counterfeiting and tracing stolen ones. They are valuable in quality control, as once a defect is found in the production of a batch of product. Serial numbers may be used to identify individual physical or intangible objects, the purpose and application is different. A software serial number, otherwise called product key, is not embedded in the software. The software will function if a potential user enters a valid product code. The vast majority of codes are rejected by the software. If an unauthorised user is found to be using the software, the term serial number is sometimes used for codes which do not identify a single instance of something. It takes its name from the library use of the word serial to mean a periodical. Certificates and certificate authorities are necessary for use of cryptography. These depend on applying mathematically rigorous serial numbers and serial number arithmetic, the term serial number is also used in military formations as an alternative to the expression service number. Because of this, the number is sometimes called a tail number. LZ548/G—the prototype de Havilland Vampire jet fighter, or ML926/G—a de Havilland Mosquito XVI experimentally fitted with H2S radar, the serial number follows the aircraft throughout its period of service. In 2009 the U. S. FDA published draft guidance for the industry to use serial numbers on prescription drug packages. This measure will enhance the traceability of drugs and help to prevent counterfeiting, Serial numbers are often used in network protocols. However, most sequence numbers in computer protocols are limited to a number of bits
21.
LED
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A light-emitting diode is a two-lead semiconductor light source. It is a p–n junction diode, which emits light when activated, when a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light is determined by the band gap of the semiconductor. LEDs are typically small and integrated optical components may be used to shape the radiation pattern, appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared light. Infrared LEDs are still used as transmitting elements in remote-control circuits. The first visible-light LEDs were also of low intensity and limited to red, modern LEDs are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness. Early LEDs were often used as indicator lamps for electronic devices and they were soon packaged into numeric readouts in the form of seven-segment displays and were commonly seen in digital clocks. Recent developments in LEDs permit them to be used in environmental, LEDs have allowed new displays and sensors to be developed, while their high switching rates are also used in advanced communications technology. LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. Light-emitting diodes are now used in applications as diverse as aviation lighting, automotive headlamps, advertising, general lighting, traffic signals, camera flashes, as of 2017, LED lights home room lighting are as cheap or cheaper than compact fluorescent lamp sources of comparable output. They are also more energy efficient and, arguably, have fewer environmental concerns linked to their disposal. Electroluminescence as a phenomenon was discovered in 1907 by the British experimenter H. J. Round of Marconi Labs, using a crystal of silicon carbide, russian inventor Oleg Losev reported creation of the first LED in 1927. His research was distributed in Soviet, German and British scientific journals, rubin Braunstein of the Radio Corporation of America reported on infrared emission from gallium arsenide and other semiconductor alloys in 1955. Braunstein observed infrared emission generated by simple diode structures using gallium antimonide, GaAs, indium phosphide, in 1957, Braunstein further demonstrated that the rudimentary devices could be used for non-radio communication across a short distance. As noted by Kroemer Braunstein …had set up a simple optical communications link, the emitted light was detected by a PbS diode some distance away. This signal was fed into an amplifier and played back by a loudspeaker. Intercepting the beam stopped the music and we had a great deal of fun playing with this setup. This setup presaged the use of LEDs for optical communication applications, by October 1961, they had demonstrated efficient light emission and signal coupling between a GaAs p-n junction light emitter and an electrically-isolated semiconductor photodetector
22.
Conventional PCI
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Conventional PCI, often shortened to PCI, is a local computer bus for attaching hardware devices in a computer. PCI is the initialism for Peripheral Component Interconnect and is part of the PCI Local Bus standard, the PCI bus supports the functions found on a processor bus but in a standardized format that is independent of any particular processors native bus. Devices connected to the PCI bus appear to a bus master to be connected directly to its own bus and are assigned addresses in the address space. It is a bus, synchronous to a single bus clock. Attached devices can take either the form of an integrated circuit fitted onto the motherboard itself or a card that fits into a slot. The PCI Local Bus was first implemented in IBM PC compatibles and it has subsequently been adopted for other computer types. Typical PCI cards used in PCs include, network cards, sound cards, modems, extra ports such as USB or serial, TV tuner cards, PCI video cards replaced ISA and VESA cards until growing bandwidth requirements outgrew the capabilities of PCI. The preferred interface for video cards then became AGP, itself a superset of conventional PCI and these have one locating notch in the card. Version 2.0 of the PCI standard introduced 3.3 V slots, universal cards, which can operate on either voltage, have two notches. Version 2.1 of the PCI standard introduced optional 66 MHz operation, a server-oriented variant of conventional PCI, called PCI-X operated at frequencies up to 133 MHz for PCI-X1.0 and up to 533 MHz for PCI-X2.0. An internal connector for laptop cards, called Mini PCI, was introduced in version 2.2 of the PCI specification, the PCI bus was also adopted for an external laptop connector standard – the CardBus. The first PCI specification was developed by Intel, but subsequent development of the standard became the responsibility of the PCI Special Interest Group, Conventional PCIs heyday in the desktop computer market was approximately 1995–2005. PCI and PCI-X have become obsolete for most purposes, however, they are common on modern desktops for the purposes of backwards compatibility. Many kinds of devices available on PCI expansion cards are now commonly integrated onto motherboards or available in USB. Work on PCI began at Intels Architecture Development Lab c. 1990, a team of Intel engineers defined the architecture and developed a proof of concept chipset and platform partnering with teams in the companys desktop PC systems and core logic product organizations. PCI was immediately put to use in servers, replacing MCA, in mainstream PCs, PCI was slower to replace VESA Local Bus, and did not gain significant market penetration until late 1994 in second-generation Pentium PCs. By 1996, VLB was all but extinct, and manufacturers had adopted PCI even for 486 computers, EISA continued to be used alongside PCI through 2000. Apple Computer adopted PCI for professional Power Macintosh computers in mid-1995, the 64-bit version of plain PCI remained rare in practice though, although it was used for example by all G3 and G4 Power Macintosh computers
23.
Motherboard
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A motherboard is the main printed circuit board found in general purpose microcomputers and other expandable systems. It holds and allows communication between many of the electronic components of a system, such as the central processing unit and memory. In very old designs, copper wires were the discrete connections between card connector pins, but printed circuit boards soon became the standard practice, the Central Processing Unit, memory, and peripherals were housed on individual printed circuit boards, which were plugged into the backplate. The ubiquitous S-100 bus of the 1970s is an example of type of backplane system. During the late 1980s and 1990s, it became economical to move a number of peripheral functions onto the motherboard. Business PCs, workstations, and servers were more likely to need expansion cards, either for more robust functions, or for higher speeds, laptop and notebook computers that were developed in the 1990s integrated the most common peripherals. This even included motherboards with no upgradeable components, a trend that would continue as smaller systems were introduced after the turn of the century, memory, processors, network controllers, power source, and storage would be integrated into some systems. A motherboard provides the connections by which the other components of the system communicate. Unlike a backplane, it contains the central processing unit and hosts other subsystems. A typical desktop computer has its microprocessor, main memory, an important component of a motherboard is the microprocessors supporting chipset, which provides the supporting interfaces between the CPU and the various buses and external components. This chipset determines, to an extent, the features and capabilities of the motherboard, modern motherboards include, Sockets in which one or more microprocessors may be installed. In the case of CPUs in ball grid array packages, such as the VIA C3, as of 2007, some graphics cards require more power than the motherboard can provide, and thus dedicated connectors have been introduced to attach them directly to the power supply. Connectors for hard drives, typically SATA only, disk drives also connect to the power supply. Additionally, nearly all motherboards include logic and connectors to support commonly used devices, such as USB for mouse devices. Early personal computers such as the Apple II or IBM PC included only this minimal peripheral support on the motherboard, occasionally video interface hardware was also integrated into the motherboard, for example, on the Apple II and rarely on IBM-compatible computers such as the IBM PC Jr. Additional peripherals such as disk controllers and serial ports were provided as expansion cards, given the high thermal design power of high-speed computer CPUs and components, modern motherboards nearly always include heat sinks and mounting points for fans to dissipate excess heat. Motherboards are produced in a variety of sizes and shapes called computer form factor, however, the motherboards used in IBM-compatible systems are designed to fit various case sizes. As of 2007, most desktop computer motherboards use the ATX standard form factor — even those found in Macintosh and Sun computers, a cases motherboard and PSU form factor must all match, though some smaller form factor motherboards of the same family will fit larger cases
24.
DMZ (computing)
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The name is derived from the term demilitarized zone, an area between nation states in which military operation is not permitted. In the military sense, a DMZ is not seen as belonging to either party bordering it. In this case, the hosts most vulnerable to attack are those that provide services to users outside of the local network, such as e-mail, Web. Because of the potential of these hosts suffering an attack. Hosts in the DMZ are permitted to have only limited connectivity to hosts in the internal network. In such architecture, the DMZ usually has the application firewall, any service that is being provided to users on the external network can be placed in the DMZ. The web servers can communicate with database servers either directly or through a firewall for security reasons. The mail server inside the DMZ passes incoming mail to the secured/internal mail servers, for security, compliance with legal standards such as HIPAA, and monitoring reasons, in a business environment, some enterprises install a proxy server within the DMZ. This has the benefits, Obliges internal users to use the proxy server for Internet access. Reduced Internet access bandwidth requirements since some web content may be cached by the proxy server, simplifies recording and monitoring of user activities. A reverse proxy server, like a server, is an intermediary. Instead of providing a service to internal users wanting to access an external network, for example, a back office application access, such as an email system, could be provided to external users but the remote user would not have direct access to their email server. Only the reverse proxy server can physically access the email server. This is a layer of security, which is particularly recommended when internal resources need to be accessed from the outside. There are many different ways to design a network with a DMZ, two of the most basic methods are with a single firewall, also known as the three legged model, and with dual firewalls. These architectures can be expanded to very complex architectures depending on the network requirements. A single firewall with at least 3 network interfaces can be used to create a network containing a DMZ. The firewall becomes a point of failure for the network
25.
Infineon Technologies
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As of 30 September 2016, Infineon had 36,299 employees worldwide. In fiscal year 2016, the company achieved sales of €6.473 billion, on 1 May 2006, Infineons Memory Products division was carved out as a distinct company called Qimonda AG, which at its height employed about 13,500 people worldwide. Qimonda was listed on the New York Stock Exchange until 2009, Infineon Technologies AG, in Neubiberg near Munich, offers semiconductors and systems for automotive, industrial, and multimarket sectors, as well as chipcard and security products. With a global presence, Infineon operates through its subsidiaries in the USA, from Milpitas, California, Infineon has a number of facilities in Europe, one in Dresden, Germany, Europes microelectronic, and emerging technologies center. Infineons high power segment is in Warstein, Germany, Villach and Graz in Austria, Cegléd in Hungary, and Italy. It also runs R&D centers in France, Singapore, Romania, Taiwan, UK and India, as well as units in Singapore, Malaysia, Indonesia. Theres also a Shared Service Center in Maia, Portugal, Infineon is listed in the DAX index of the Frankfurt Stock Exchange. After several restructurings, Infineon today comprises four areas, Infineon provides semiconductor products for use in powertrains. The product portfolio includes microcontrollers, power semiconductors and sensors, in fiscal year 2013, sales amounted to €1,714 million for the ATV segment. The industrial division of the company includes power semiconductors and modules which are used for generation, transmission and consumption of electrical energy and its application areas include control of electric drives for industrial applications and household appliances, modules for renewable energy production, conversion and transmission. This segment achieved sales of €651 million in fiscal year 2013, the division Power Management & Control sums up the business with semiconductor components for efficient power management or high-frequency applications. In fiscal year 2013 PMM generated €987 million, the CCS business provides microcontrollers for mobile phone SIM cards, payment cards, security chips and chip-based solutions for passports, identity cards and other official documents. Infineon delivers a significant number of chips for the new German identity card, in addition, CCS provides solutions for applications with high security requirements such as pay television and Trusted Computing. CCS achieved €463 million in fiscal year 2013, Infineon is the number 1 in embedded security. The former memory chip division was carved out in 2006 as Infineon’s subsidiary Qimonda, in January 2009, Qimonda filed for bankruptcy with the district court in Munich. On 7 July 2009, Infineon Technologies AG agreed by contract with the U. S. investor Golden Gate Capital on the sale of its Wireline Communications for €250 million, the resulting new company is now known as Lantiq. On 31 January 2011, the sale of the segment of wireless solutions to Intel was completed. The resulting new company has approximately 3,500 employees and now operates as Intel Mobile Communications, in July 2016, Infineon announced it agreed to buy the North Carolina-based company Wolfspeed from Cree Inc. for $850 million in cash
26.
Broadcom
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Broadcom Corporation was an American fabless semiconductor company that made products for the wireless and broadband communication industry. It was acquired by Avago Technologies in 2016 and currently operates as an owned subsidiary of the merged entity called Broadcom Limited. The division is headquartered in Irvine, California, Broadcom Corporation was founded by professor-student pair Henry Samueli and Henry Nicholas from UCLA in 1991. In 1995 the company moved from its Westwood, Los Angeles office to Irvine, in 1998, Broadcom became a public company on the NASDAQ exchange and now employs approximately 11,750 people worldwide in more than 15 countries. Broadcom is among Gartners Top 10 Semiconductor Vendors by revenue, Broadcom first landed on the Fortune 500 in 2009. In 2012, Broadcoms total revenue was $8.01 billion, in 2013, Broadcom stood at No.327 on the Fortune 500, having climbed 17 places from its 2012 ranking of No.344. In May 28,2015 chip maker Avago Technologies Ltd. agreed to buy Broadcom Corp. for $37 billion in cash, at closing, which completed on February 1,2016, Broadcom shareholders will hold 32% of the new Singapore-based company to be called Broadcom Limited. Hock Tan, Avago President and CEO, will be the new CEO of the new combined company, Dr. Samueli will be Chief Technology Officer and member of the combined companys board. And Dr. Nicholas will serve in an advisory role within the new company. The new merged entity is named Broadcom Limited but inherits the ticker symbol AVGO, the BRCM ticker symbol was retired. In May 2016 Cypress Semiconductor announced that it will acquire Broadcom Corporations full portfolio of IoT products for $550 million, under the deal, Cypress acquires Broadcoms IoT products and intellectual property for Wi-Fi, Bluetooth and ZigBee connectivity, as well as Broadcoms WICED platform and SDK for developers. Broadcoms product line spans computer and telecommunication networking, the company has products for enterprise/metropolitan high-speed networks, products include transceiver and processor ICs for Ethernet and wireless LANs, cable modems, digital subscriber line, servers, home networking devices and cellular phones. It is also known for a series of high-speed encryption co-processors, offloading this processor-intensive work to a dedicated chip and this has many practical benefits for e-commerce, and PGP or GPG secure communications. Major customers include Apple, Hewlett-Packard, Motorola, IBM, Dell, Asus, Lenovo, Linksys, Logitech, Nintendo, Nokia Siemens Networks, Nortel, TiVo, Tenda, in September 2011, Broadcom shut down its digital TV operations. Broadcom also shut down its Blu-ray chip business, the closure of these businesses began on September 19,2011. On June 2,2014, Broadcom announced intentions to exit the cellular baseband business, Vendors have included Broadcom NICs in their products. For example, the Dell blade-server M610 has two embedded Gigabit NetXtreme 5709 NICs, the latest member of the Trident family is the Trident II XGS which can support up to 32 x 40G ports or 104 x 10G ports on a single chip. Broadcom Crystal HD does video acceleration, more specifically, Broadcom would provide Bluetooth connectivity for Wiis controller
27.
SK Hynix
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SK hynix Inc. is a South Korean memory semiconductor supplier of dynamic random access memory chips and flash memory chips. Hynix is the worlds second-largest memory chipmaker and the worlds fifth-largest semiconductor company, founded as Hyundai Electronic Industrial Co. Ltd. in 1983 and known as Hyundai Electronics, the company has manufacturing sites in Korea, the US, China and Taiwan. In 2012, when SK Telecom became its major shareholder, Hynix merged to SK Group, the companys shares are traded on the Korea Stock Exchange, and the Global Depository shares are listed on the Luxembourg Stock Exchange. Hynix memory is used by Apple in some of their iMac, apples latest A9 chipset is onboard together with a SK Hynix RAM module believed to be likely the same 2 GB LPDDR4 mobile DRAM found in the iPhone 6s. Hynix memory is used by Asus in their Google-branded Nexus 7 tablet, an OEM provider for IBM System x servers. Dell and Hewlett-Packard have also used Hynix memory as OEM equipment, other products that use Hynix memory include DVD players, cellular phones, set-top boxes, personal digital assistants, networking equipment, and hard disk drives. It is one of the earliest PC clones marketed toward consumers instead of business, in January 2010, Hynix Semiconductor Inc was put up for sale in an auction valued at close to $3 billion. On August 31,2010, HP announced collaboration with Hynix to bring memristor to high volume manufacturing step,2012 SK Group, the third-largest conglomerate in South Korea, acquired a 21. 05% stake in Hynix. 2013 Fab 1 and Fab 2 in China both suffered a fire which took the factories offline temporarily
28.
System on a chip
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A system on a chip or system on chip is an integrated circuit that integrates all components of a computer or other electronic systems. It may contain digital, analog, mixed-signal, and often radio-frequency functions—all on a single substrate, SoCs are very common in the mobile computing market because of their low power-consumption. A typical application is in the area of embedded systems, the contrast with a microcontroller, SoC integrates microcontroller with advanced peripherals like graphics processing unit, Wi-Fi module, or coprocessor. As long as we remember that the SoC does not necessarily contain built-in memory, in general, we can distinguish three types of SoC. SoC built around a microcontroller, SoC built around a microprocessor, a separate category may be Programmable SoC, part of elements is not permanently defined and can be programmable in a manner analogous to the FPGA or CPLD. When it is not feasible to construct a SoC for a particular application, in large volumes, SoC is believed to be more cost-effective than SiP since it increases the yield of the fabrication and because its packaging is simpler. Another option, as seen for example in cell phones, is package on package stacking during board assembly. The SoC includes processors and numerous digital peripherals, and comes in a ball grid package with lower and upper connections. The lower balls connect to the board and various peripherals, with the balls in a ring holding the memory buses used to access NAND flash. Memory packages could come from multiple vendors, DMA controllers route data directly between external interfaces and memory, bypassing the processor core and thereby increasing the data throughput of the SoC. A SoC consists of both the hardware, described above, and the controlling the microcontroller, microprocessor or DSP cores, peripherals. The design flow for a SoC aims to develop hardware and software in parallel. Most SoCs are developed from pre-qualified hardware blocks for the elements described above. Of particular importance are the protocol stacks that drive industry-standard interfaces like USB, the hardware blocks are put together using CAD tools, the software modules are integrated using a software-development environment. Once the architecture of the SoC has been defined, any new elements are written in an abstract language termed RTL which defines the circuit behaviour. These elements are connected together in the same RTL language to create the full SoC design, chips are verified for logical correctness before being sent to foundry. This process is called functional verification and it accounts for a significant portion of the time, with the growing complexity of chips, hardware verification languages like SystemVerilog, SystemC, e, and OpenVera are being used. Bugs found in the stage are reported to the designer
29.
VxWorks
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VxWorks is a real-time operating system developed as proprietary software by Wind River of Alameda, California, US. VxWorks supports Intel, MIPS, PowerPC, SH-4, and ARM architectures, the RTOS can be used in multicore asymmetric multiprocessing, symmetric multiprocessing, and mixed modes and multi-OS designs on 32- and 64-bit processors. VxWorks comes with the kernel, middleware, board support packages, Wind River Workbench development suite, in its latest release, VxWorks 7, the RTOS has been re-engineered for modularity and upgradeability so the OS kernel is separate from middleware, applications and other packages. Scalability, security, safety, connectivity, and graphics have improved to address Internet of Things needs. VxWorks started in the late 1980s as a set of enhancements to a simple RTOS called VRTX sold by Ready Systems, Wind River acquired rights to distribute VRTX and significantly enhanced it by adding, among other things, a file system and an integrated development environment. In 1987, anticipating the termination of its contract by Ready Systems. VxWorks key milestones are, 1980s, VxWorks adds support for 32-bit processors, 1990s, VxWorks 5 becomes the first RTOS with a networking stack. 2000s, VxWorks 6 supports SMP and adds derivative industry-specific platforms, 2010s, VxWorks adds support for 64-bit processing and introduces VxWorks 7 for IoT in 2016. VxWorks supports Intel, MIPS, PowerPC, SH-4, and ARM architectures, the RTOS can be used in multicore asymmetric multiprocessing, symmetric multiprocessing, and mixed modes and multi-OS designs on 32- and 64-bit processors. The VxWorks Core Platform consists of a set of runtime components, the run time components are an operating system, software for applications support and hardware support. VxWorks core development tools are compilers such as Diab, GNU, the system also includes productivity tools such as its Workbench development suite and Intel tools and development support tools for asset tracking and host support. The platform is a modular, vendor-neutral, open system that supports a range of third-party software and hardware, the OS kernel is separate from middleware, applications and other packages, which enables easier bug fixes and testing of new features. VxWorks is designed for use in embedded systems, a list of some of the features of the OS are, Multitasking kernel with preemptive and round-robin scheduling and fast interrupt response Native 64-bit operating system. User-mode applications isolated from other applications as well as the kernel via memory protection mechanisms. The following lists some of the release 7 updates and this includes the Intel x86 family, MIPS, PowerPC, Freescale ColdFire, Intel i960, SPARC, Fujitsu FR-V, SH-4 and the closely related family of ARM, StrongARM and xScale CPUs. VxWorks provides a standard board support package interface between all its supported hardware and the OS, Wind River’s BSP developer kit provides a common application programming interface and a stable environment for real-time operating system development. As is common in embedded system development, cross-compiling is used with VxWorks, development is done on a host system where an integrated development environment, including the editor, compiler toolchain, debugger, and emulator can be used. Software is then compiled to run on the target system, the Tornado IDE was used for VxWorks 5. x and was replaced by the Eclipse-based Workbench IDE for VxWorks 6. x. and later
30.
Peer-to-peer
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Peer-to-peer computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the application and they are said to form a peer-to-peer network of nodes. Peers are both suppliers and consumers of resources, in contrast to the traditional client-server model in which the consumption, while P2P systems had previously been used in many application domains, the architecture was popularized by the file sharing system Napster, originally released in 1999. The concept has inspired new structures and philosophies in many areas of human interaction, in such social contexts, peer-to-peer as a meme refers to the egalitarian social networking that has emerged throughout society, enabled by Internet technologies in general. While P2P systems had previously used in many application domains. The peer-to-peer movement allowed millions of Internet users to directly, forming groups and collaborating to become user-created search engines, virtual supercomputers. The basic concept of peer-to-peer computing was envisioned in earlier systems and networking discussions, reaching back to principles stated in the first Request for Comments. The early Internet was more open than present day, where two machines connected to the Internet could send packets to each other without firewalls and other security measures and this contrasts to the broadcasting-like structure of the web as it has developed over the years. As a precursor to the Internet, ARPANET was a successful client-server network where every participating node could request, however, ARPANET was not self-organized, and it lacked the ability to provide any means for context or content-based routing beyond simple address-based routing. Therefore, a messaging system that is often likened as an early peer-to-peer architecture was established. USENET was developed in 1979 and is a system that enforces a decentralized model of control, the basic model is a client-server model from the user or client perspective that offers a self-organizing approach to newsgroup servers. However, news servers communicate with one another as peers to propagate Usenet news articles over the group of network servers. In May 1999, with more people on the Internet, Shawn Fanning introduced the music. A peer-to-peer network is designed around the notion of equal peer nodes simultaneously functioning as both clients and servers to the nodes on the network. This model of network arrangement differs from the model where communication is usually to. Data is still exchanged directly over the underlying TCP/IP network, but at the application layer peers are able to communicate each other directly. Overlays are used for indexing and peer discovery, and make the P2P system independent from the network topology. Based on how the nodes are linked to each other within the overlay network, unstructured peer-to-peer networks do not impose a particular structure on the overlay network by design, but rather are formed by nodes that randomly form connections to each other
31.
Qualcomm Atheros
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Qualcomm Atheros is a developer of semiconductors for network communications, particularly wireless chipsets. Founded under the name T-Span Systems in 1998 by experts in signal processing and VLSI design from Stanford University, the company was renamed Atheros Communications in 2000 and it completed an initial public offering in February 2004 trading on NASDAQ under the symbol ATHR. On January 5,2011, it was announced that Qualcomm had agreed to a takeover of the company for a valuation of US$3.7 billion, when the acquisition was completed on May 24,2011, Atheros became a subsidiary of Qualcomm operating under the name Qualcomm Atheros. Qualcomm Atheros chipsets for the IEEE802.11 standard of wireless networking are used by over 30 different wireless device manufacturers, the companys first office was a converted house on Encina Avenue, Palo Alto, adjacent to a car wash and Town & Country Village. In September 1999, the moved to an office at 3145 Porter Drive, Building A. In 2000, T-Span Systems was renamed Atheros Communications and the moved to a larger office at 529 Almanor Avenue. Atheros publicly demonstrated its inaugural chipset, the worlds first WLAN implemented in CMOS technology, in 2002, Atheros launched the first dual-band wireless solution, the AR5001X802. 11a/b. In 2002, Dr. Craig H. Barratt joined Atheros as VP Technology, Craig was promoted to CEO of Atheros in March 2003, a position he retained until Atheros acquisition by Qualcomm. In 2003, the company shipped its 10-millionth wireless chip, in 2004, Atheros unveiled a number of products, including the first video chipset for mainstream HDTV-quality wireless connectivity. In 2005, Atheros introduced the industrys first MIMO-enabled WLAN chip, as well as the ROCm family of high-performance, low-power WLAN solutions for mobile handsets, in 2006, Atheros launched its XSPAN solutions, which featured a single-chip, triple-radio solution for 802. 11n. In this same year, they began to collaborate with Qualcomm on a 3G/Wi-Fi solution for CDMA, in 2008, Atheros launched the Align 1-stream 802. 11n solutions for PCs and networking equipment. In 2010, Atheros shipped its 500-millionth WLAN chipset and 100-millionth Align 1-stream chipset and they released the first HomePlug AV chipset with a 500 Mbit/s PHY rate. On February 12,2004, Atheros completed its public offering on the NASDAQ exchange trading under the symbol ATHR. Shares opened at $14 per share with 9 million offered, prices on the first day ranged up to $18.45 and closed at $17.60 per share. At the time, Atheros had approximately 170 employees, in January 2011, Qualcomm agreed to acquire Atheros at $45 per share cash. This agreement was subject to regulatory approvals. In May 2011, Qualcomm completed its acquisition of Atheros Communications for a total of US$3.7 billion, Atheros became a subsidiary of Qualcomm under the name Qualcomm Atheros. After the acquisition, the division unveiled the WCN3660 Combo Chip, which integrated dual-band Wi-Fi, Bluetooth, Qualcomm Atheros launched the Skifta media shifting application for Android and released the first HomePlug Green PHY solution at the end of the year
32.
Tomato (firmware)
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Among other notable features is the user interface, which makes heavy use of Ajax as well as an SVG-based graphical bandwidth monitor. Tomato was originally released by Jonathan Zarate in 2008, building on the code of HyperWRT, since the last release from the original developer in June 2010, continued development happens through several community-maintained mods. Fedor Kozhevnikov created an early fork, called TomatoUSB, which ceased development in November 2010. It was then forked by other developers with projects such as Tomato by Shibby becoming popular, advancedTomatos project website also contains a list of supported routers List of wireless router firmware projects Official website Virtual Tomato RAF Tomato Phoenix
33.
OpenWrt
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OpenWrt is an embedded operating system based on Linux, primarily used on embedded devices to route network traffic. The main components are Linux, util-linux, uClibc or musl, all components have been optimized for size, to be small enough for fitting into the limited storage and memory available in home routers. OpenWrt is configured using an interface, or a web interface. There are about 3500 optional software packages available for installation via the package management system. OpenWrt can run on types of devices, including CPE routers, residential gateways, smartphones, pocket computers. It is also possible to run OpenWrt on personal computers, which are most commonly based on the x86 architecture, the project came into being because Linksys built the firmware for their WRT54G series of wireless routers from publicly available code licensed under the GPL. Support was originally limited to the WRT54G series, but has since expanded to include many other chipsets, manufacturers and device types, including Plug Computers. Using this code as a base and later as a reference, some features formerly required proprietary software. With the Attitude Adjustment release of OpenWrt, all devices with 16 MB or less RAM are no longer supported as they can run out of memory easily. Older Backfire is recommended instead for bcm47xx devices, as issues for those devices came from dropping support for the legacy Broadcom target brcm-2.4, OpenWrt follows the bazaar-philosophy and is known for an abundance of options. Features include, A writable root file system, enabling users to add and this is accomplished by using overlayfs to overlay a read-only compressed SquashFS file system with a writable JFFS2 file system in a copy-on-write fashion. The package manager opkg, similar to dpkg, enables users to install, the package repository contains about 3500 packages. This contrasts with Linux-based firmwares based on file systems without the possibility to modify the installed software without rebuilding and flashing a complete firmware image. Exhaustive possibilities to configure network-related features, like, IPv4 support, IPv6 native stack, Prefix Handling, Native IPv6 configuration, IPv6 transitioning technologies, Downstream IPv6 configuration. Routing through iproute2, Quagga, BIRD, Babel etc, wireless security, Packet injection, e. g. Airpwn, lorcon, e. a. Stateful firewall, NAT and port forwarding through netfilter, additionally PeerGuardian is available Dynamically-configured port forwarding protocols UPnP and NAT-PMP through upnpd, etc. Port knocking via knockd and knock TR-069 client IPS via Snort Active queue management through the network scheduler of the Linux kernel, coDel has been backported to Kernel 3.3. Domain Name System and DHCP through Dnsmasq, MaraDNS, etc.09, in OpenWrt releases 8.09 and newer, a more capable web interface is included
34.
DD-WRT
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DD-WRT is a GNU/Linux-based firmware for wireless routers and access points. Originally designed for the Linksys WRT54G series, it now runs on a variety of models. DD-WRT is one of a handful of third-party firmware projects designed to replace manufacturers original firmware with custom firmware offering additional features or functionality, the firmware projects name was taken in part from the Linksys WRT54G model router, a home router popular in 2002–2004. DD are the German license-plate letters for vehicles from Dresden, where the BrainSlayers development team lived, WRT, also used by the OpenWrt router firmware project, comes from the generic abbreviation for Wireless RouTer, which may have been the original Linksys meaning. Buffalo Technology and other companies have shipped routers with factory-installed, customized versions of DD-WRT, in January 2016, Linksys itself started to offer DD-WRT firmware for their routers. The complete feature set depends on the version, Over the past years and this provides an ability to use various VPNs on a DD-WRT in order to secure the whole network. As a result all traffic which passes through DD-WRT router gets a VPN protection and it is possible to build a custom firmware package with the desired feature-set, working within the limitations of available ROM. All versions require at least 4 MB of flash memory, unless noted otherwise, micro+ requires at least 2 MB of flash memory plus 128 KB Common Firmware Environment storage space. Version 23 Service Pack 2 –14 September 2006 – The interface was overhauled, some additional router models are supported. Version 24 –18 May 2008 – Allows up to 16 virtual interfaces with different SSIDs and it can run on some PowerPC, IXP425-based router boards, Atheros WiSOC, and X86-based systems. It can also run to some extent on routers with low flash memory, version 24 Service Pack 1 –26 July 2008 – Contains an urgent DNS security fix for an issue in dnsmasq, site survey security fixes, longer passwords, and flexible OpenVPN configurations. It can also run on hardware, including WRT300 v1.1, WRT310N, WRT600N, Tonze AP42X Pronghorn SBC, Ubiquiti LSX and Netgear, Belkin. From the last version forward, builds have been released on DD-WRT forums for different routers. Some of these are considered highly stable while others are not working at all, classical features of routers can be fully enabled with version 24 Service Pack 2 build 14929 standard, which can be installed with the micro version first. BusyBox List of router firmware projects Official website DD-WRT software version control
35.
MIMO
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In radio, multiple-input and multiple-output, or MIMO, is a method for multiplying the capacity of a radio link using multiple transmit and receive antennas to exploit multipath propagation. MIMO has become an element of wireless communication standards including IEEE802. 11n, IEEE802. 11ac, HSPA+, WiMAX. More recently, MIMO has been applied to communication for 3-wire installations as part of ITU G. hn standard. At one time, in wireless the term MIMO referred to the use of antennas at the transmitter. In modern usage, MIMO specifically refers to a technique for sending and receiving more than one data signal simultaneously over the same radio channel by exploiting multipath propagation. MIMO is fundamentally different from smart antenna techniques developed to enhance the performance of a data signal, such as beamforming. Methods were developed to improve the performance of radio networks. Space-division multiple access uses directional or smart antennas to communicate on the frequency with users in different locations within range of the same base station. An SDMA system was proposed by Richard Roy and Björn Ottersten, researchers at ArrayComm and their US patent describes a method for increasing capacity using an array of receiving antennas at the base station with a plurality of remote users. Arogyaswami Paulraj and Thomas Kailath proposed an SDMA-based inverse multiplexing technique in 1993, Paulraj was awarded the prestigious Marconi Prize in 2014 for his pioneering contributions to developing the theory and applications of MIMO antennas. The paper also identified practical solutions for modulation, coding, synchronization, later that year Gerard J. Foschini submitted a paper that also suggested it is possible to multiply the capacity of a wireless link using what the author described as layered space-time architecture. Greg Raleigh, V. K. Jones, and Michael Pollack founded Clarity Wireless in 1996, cisco Systems acquired Clarity Wireless in 1998. Bell Labs built a laboratory prototype demonstrating its V-BLAST technology in 1998, Arogyaswami Paulraj founded Iospan Wireless in late 1998 to develop MIMO-OFDM products. Iospan was acquired by Intel in 2003, V-BLAST was never commercialized, and neither Clarity Wireless nor Iospan Wireless shipped MIMO-OFDM products before being acquired. MIMO technology has been standardized for wireless LANs, 3G mobile phone networks, greg Raleigh and V. K. Jones founded Airgo Networks in 2001 to develop MIMO-OFDM chipsets for wireless LANs. The Institute of Electrical and Electronics Engineers created a group in late 2003 to develop a wireless LAN standard delivering at least 100 Mbit/s of user data throughput. There were two competing proposals, TGn Sync was backed by companies including Intel and Philips, and WWiSE was supported by companies including Airgo Networks, Broadcom. Both groups agreed that the 802. 11n standard would be based on MIMO-OFDM with 20 MHz and 40 MHz channel options, TGn Sync, WWiSE, and a third proposal were merged to create what was called the Joint Proposal
