Requirements Token Ring

GÖTTERDAMMERÜNG — A World Premiere, Today At San Francisco Opera

GÖTTERDAMMERÜNG – the final chapter of Wagner’s The Ring of the Nibelung reaches its transcendent climax with this world-premiere production, a suspenseful tale of bravery and sacrifice, treachery and betrayal, destruction and renewal. The sacred union of Siegfried and Brünnhilde is threatened by three scheming siblings, one of whom was sired by Alberich to take possession of the ring. Driven by greed, their actions inevitably lead to chaos and destruction, until Brünnhilde—wise, pure of heart, heroic—steps forward to return the universe to its natural order in an act of self-sacrifice. Sung in German with English supertitles, the approximate running time is 5 hours, 15 minutes including two intermissions.

All production photos by Cory Weaver

THE PLOT: Siegfried gives Brünnhilde the ring as a token of their union and sets off for new adventures. He meets the self-serving siblings Gunther and Gutrune and their half-brother Hagen, the son of Alberich. Seeking the ring, Hagen uses a potion to trick Siegfried into abandoning Brünnhilde, who joins him in plotting revenge. Hagen murders Siegfried, and Brünnhilde, understanding too late the deception, orders a funeral pyre built for Siegfried. As she strides into the fire, the flames rise to destroy Valhalla, the Rhine overflows its banks and the ring is returned to its rightful owners, the Rhinemaidens. The era of the gods is now over.

MEET THE ARTISTS

NINA STEMME (Brünnhilde) makes her Ring cycle role debut as Brünnhilde this summer, having previously performed the role in the Company’s Die Walküre in 2010. She made her San Francisco Opera debut in 2004 as Senta (Der Fliegende Holländer) and appeared later that season in a concert in honor of Donald Runnicles’s fiftieth birthday. The Swedish soprano has performed Brünnhilde (Siegfried) with the Vienna State Opera, a role that she reprises with that company last season. A former winner of the Plácido Domingo Competition and finalist of the BBC Cardiff Singer of the World Competition, Stemme regularly sings with the world’s leading opera companies, including the Metropolitan Opera; the Royal Opera, Covent Garden; Paris Opera; the Vienna State Opera; Frankfurt Opera; Zurich Opera; Stockholm’s Royal Opera; Madrid’s Teatro Real; and the Gran Teatre del Liceu in Barcelona.

The History of Networking | GallMedia

1960s

In the 1960s, computer networking was essentially synonymous with mainframe computing and telephony services, and the distinction between local and wide area networks did not yet exist. Mainframes were typically “networked” to a series of dumb terminals with serial connections running on RS-232 or some other electrical interface. If a terminal in one city needed to connect with a mainframe in another city, a 300-baud long-haul modem would use the existing analog Public Switched Telephone Network (PSTN) to form the connection. The technology was primitive indeed, but it was an exciting time nevertheless.

The quality and reliability of the PSTN increased significantly in 1962 with the introduction of pulse code modulation (PCM), which converted analog voice signals into digital sequences of bits. DS0 (Digital Signal Zero) became the basic 64-Kbps channel, and the entire hierarchy of the digital telephone system was soon built on this foundation. Next, a device called the channel bank was introduced. It took 24 separate DS0 channels and combined them using time-division multiplexing (TDM) into a single 1.544-Mbps channel called DS1 or T1. (In Europe, 30 DS0 channels were combined to make E1.) When the backbone of the Bell system became digital, transmission characteristics improved due to higher quality and less noise. This was eventually extended all the way to local loop subscribers using ISDN. The first commercial touch-tone phone was also introduced in 1962.

The first communication satellite, Telstar, was launched in 1962. This technology did not immediately affect the networking world because of the latency of satellite links compared to undersea cable communications, but it eventually surpassed transoceanic underwater telephone cables (which were first deployed in 1965 and could carry 130 simultaneous conversations) in carrying capacity. In fact, in 1960 scientists at Bell Laboratories transmitted a communication signal coast to coast across the United States by bouncing it off the moon. Unfortunately, the moon wouldn’t sit still! By 1965, the first commercial communication satellites (such as Early Bird) were deployed.

1970s

While the 1960s were the decade of the mainframe, the 1970s gave rise to Ethernet, which today is by far the most popular LAN technology. Ethernet was born in 1973 in Xerox’s research lab in Palo Alto, California. (An earlier experimental network called ALOHAnet was developed in 1970 at the University of Hawaii.) The original Xerox networking system was known as X-wire and worked at 2.94 Mbps. X-wire was experimental and was not used commercially, although a number of Xerox Alto workstations for word processing were networked together in the White House using X-wire during the Carter administration. In 1979, Digital Equipment Corporation (DEC), Intel, and Xerox formed the DIX consortium and developed the specification for standard 10-Mbps Ethernet, or thicknet, which was published in 1980. This standard was revised and additional features were added in the following decade.

Network World

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Understanding token ring protocols and standards

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Network design, principles and applications