Jumat, 19 September 2008

topologi jaringan

Topologi jaringan
beberapa komputer yang saling berhubungan saling berhubungan satu sama lain.

Jaringan komputer adalah rangkaian komputer yang tersusun secara seri yang dapat melakukan pertukaran data maupun informasi.

Dalam jaringan dikenal yang namanya TOPOLOGI jaringan. Topologi jaringan merupakan rangkaian beberapa komputer yang saling berhubungan satu sama lain. Adapun jenis-jenis topologi jaringan adalah se bagai berikut :

1. Topologi Bus

Pada topologi ini komputer server dan workstation dihubungkan secara berantai melalui kabel tunggal. Topologi ini mudah dikembangkan dan sederhana, namun bila salah satu workstation mengalami permasalahan maka yang lain akan terpengaruh. Berikut gambar topoogi bus.

2. Topologi Ring (Cincin)

Topologi ini mirip dengan topologi bus, bedanya topologi ring ujungnya saling berhubungan seolah membentuk lingkaran cincin. Pada topologi ini data mengalir searah, artinya seluruh komputer dalam jaringan akan ikut ambil bagian dalam mengolah informasi yang lewat, sehingga bila salah satu rusak maka akan berpengaruh terhadap keseluruhan jaringan. Berikut gambar topologi ring.


3. Topologi Star (Bintang)

Dalam topologi ini, setiap komputer dihubungkan secara langsung melalui media perantara berupa hub/switch. Dalam praktiknya, pembangunan sebuah jaringan biasanya tidak menggunakan satu topologi saja, melainkan gabungan dari beberapa topologi yang ada. Berikut gambar topologi star (Bintang).

Sebenarnya topologi jaringan bukan hanya 3 contoh diatas, akan tetapi ada banyak topologi jaringan. Namun yang paling sering di jumpai dalam praktik adalah ketiga contoh topologi diatas.

Rabu, 17 September 2008

Rock and roll
Main article: Rock and roll

Rock and roll evolved in the United States in the late 1940s and early 1950s, and quickly spread to the rest of the world. Its immediate origins lay in a mixing together of various popular musical genres of the time, including rhythm and blues, gospel music, and country and western. In 1951, Cleveland, Ohio disc jockey Alan Freed began playing rhythm and blues music for a multi-racial audience, and is credited with first using the phrase "rock and roll" to describe the music.

There is much debate as to what should be considered the first rock & roll record. One leading contender is "Rocket 88" by Jackie Brenston and his Delta Cats (in fact, Ike Turner and his band The Kings of Rhythm), recorded by Sam Phillips for Sun Records in 1951. Four years later, Bill Haley's "Rock Around the Clock" (1955) became the first rock and roll song to top Billboard magazine's main sales and airplay charts, and opened the door worldwide for this new wave of popular culture. Rolling Stone magazine argued in 2004 that "That's All Right (Mama)" (1954), Elvis Presley's first single for Sun Records in Memphis, was the first rock and roll record[2]. But, at the same time, Big Joe Turner's "Shake, Rattle & Roll", later covered by Haley, was already at the top of the Billboard R&B charts. Other artists with early rock and roll hits included Chuck Berry, Bo Diddley, Fats Domino, Little Richard, Jerry Lee Lewis and Gene Vincent.

The 1950s saw the growth in popularity of the electric guitar, and the development of a specifically rock and roll style of playing through such exponents as Berry, Link Wray, and Scotty Moore. It also saw major developments in recording technology such as multitrack recording developed by Les Paul, and the electronic treatment of sound by such innovators as Joe Meek. All these developments were important influences on later rock music.

The social effects of rock and roll were worldwide and massive. Far beyond simply a musical style, rock and roll influenced lifestyles, fashion, attitudes, and language. In addition, rock and roll may have helped the cause of the civil rights movement because both African American teens and white American teens enjoyed the music. However, by the early 1960s, much of the initial musical impetus and social radicalism of rock and roll had become dissipated, with the growth of teen idols, an emphasis on dance crazes, and the development of lightweight teenage pop music.
Early British rock
Main article: British rock

In the United Kingdom the trad jazz movement brought visiting blues music artists to Britain, While BAC was developing the Concorde, Lonnie Donegan's 1955 hit "Rock Island Line" was a major influence, and helped to develop the trend of skiffle music groups throughout the country, including John Lennon's the Quarry Men. Britain developed a major rock and roll scene, without the race barriers which kept "race records" or rhythm and blues separate in the U.S.

Cliff Richard had the first British rock 'n' roll hit with "Move It", effectively ushering in the sound of British rock. At the start of the 1960s, his backing group The Shadows was one of a number of groups having success with surf music instrumentals. And while rock 'n' roll was fading into lightweight pop and schmaltzy ballads, at clubs and local dances British rock groups, heavily influenced by blues-rock pioneers like Alexis Korner, were starting to play with an intensity and drive seldom found in white American acts.
The Who performing in 2007
(on left: Roger Daltrey, on right: Pete Townshend), with Zak Starkey (drums) and John "Rabbit" Bundrick (keyboards)
The Rolling Stones in the 1960s. From left: Jagger, Jones, Richards, Wyman and Watts.

By the end of 1962, the British rock scene had started with groups like the Beatles drawing on a wide range of American influences including soul music, rhythm and blues and surf music. Initially, they reinterpreted standard American tunes, playing for dancers doing the twist, for example. These groups eventually infused their original rock compositions with increasingly complex musical ideas and a distinctive sound.

In mid-1962 The Rolling Stones started as one of a number of groups increasingly showing blues influence, along with The Animals and The Yardbirds. In late 1964, The Kinks, The Who and The Pretty Things represented the new Mod style. Towards the end of the decade, British rock groups began to explore psychedelic musical styles that made reference to the drug subculture and hallucinogenic experiences.
http://en.wikipedia.org/wiki/Rock_music