Apple Inc's iPhone 4S finally went on sale in stores around the globe on Friday, with fans snapping up the final gadget unveiled during Steve Jobs' lifetime, many buying the phone as a tribute to the former Apple boss.

I think a lot of people are going to buy the iPhone 4S because it was the last iPhone Steve worked on, said Wil Batterham, 15, who with his school friend Tom Mosca were the first to buy the new phone in Sydney's Apple store.

People are saying it was named after him, like iPhone 4S, for Steve, said Batterham, clutching his new phone.

Asked what will be the first function they use on the iPhone 4S, Mosca said he would ask the new iPhone's voice-activated personal assistant software: Where's Steve?.

CEO Tim Cook and his executive team hope the first device launched without Apple's former visionary leader at the helm will safeguard their global market share lead.

Samsung, Apple's arch-rival with smartphones powered by Google's Android software, expects to overtake Apple as the world's biggest smartphone vendor in terms of units sold in the third quarter.

The iPhone 4S -- introduced to the world just a day before Jobs died -- was dubbed a disappointment because it fell short of being a revolution in design, but glowing reviews centered around its Siri voice-activated software have since helped it set a record pace in initial, online sales orders.

Apple fans showed no disappointment in Sydney on Friday as they purchased the phone, ahead of sales in Japan, Germany, France, Britain and North America.

Hundreds queued around the block of the Sydney Apple store, many rugged up against the chilly morning, as Apple staff chatted and clapped a countdown to the store opening. Apple's 13 Australian stores were the first to open their doors at 8.00 a.m. local time (2100 GMT, Thursday) to sell the iPhone 4S.

The vast majority of iPhone 4S buyers at the Sydney store appeared to be existing Apple customers, many having bought the original iPhone and upgrades each time.

Only one out of 10 people surveyed by Reuters was a new Apple customer. That buyer was replacing his HTC smartphone with the new iPhone 4S.

I have been waiting for the iPhone 5 for a long time. But since Jobs died, I wanted to make sure I had a new iPhone with some advantages over the old, said Mark Du, referring to his concern over future Apple gadgets without Jobs at the helm.

Apple said it did not release sales figures on launch day, so gauging the initial sales may be difficult. Apple said it had taken more than 1 million online orders in the first 24 hours after its release, exceeding the 600,000 for the iPhone 4, though that model was sold in fewer countries.

Some analysts expect fourth-quarter iPhone shipments of as much as 30 million or more, almost double from a year ago.

Apple's fifth-generation iPhone uses chips from Qualcomm Inc, Toshiba and a host of smaller semiconductor companies, according to repair firm iFixit, which cracked the device open on Thursday.

SPEECH RECOGNITION A WINNER

Analysts say Apple CEO Cook needs to move out from under his former mentor's enormous shadow soon, and avoid clinging to the Jobs' mystique to preserve its brand.

Apple fans in Sydney made sure to remember Jobs as part of the iPhone 4S launch, with a small flower, candle and photo shrine erected outside the glass-fronted store.

The iPhone -- seen as the market's gold standard -- is Apple's highest-margin product and accounts for 40 percent of its annual revenue. It is the world's biggest selling smartphone, for now maintaining a slim market-share lead over Samsung's Galaxy, at 18.4 versus 17.8 percent worldwide.

In a sign of how tough the competition is, two doors along from the Sydney Apple store, Samsung has been selling its new Galaxy SII for only A$2 to its first 10 customers each day, prompting Samsung fans to also camp out on the footpath.

But analysts point to several factors in Apple's favor: a $199 price that matches up well with rival devices such as Amazon.com Inc's Fire tablet; availability promised on more than 100 carriers by the end of 2011, far more than its predecessors; and glowing reviews.

Apple's iconic smartphone comes with a faster processor and a better and more light-sensitive camera, but little else to separate it from its predecessor. But tech experts say the real gems lie beneath the phone's familiar sleek casing.

Influential reviewers Walt Mossberg and David Pogue raved about Siri -- a voice-command activated assistant that responds to spoken commands and questions in context, such as queries about the weather or a friend's phone number.

I'm buying it mainly for the voice activated Siri, its like your own personal secretary, said Shane Gray, 42, one of the Sydney buyers.

(Reporting by Michael Perry in SYDNEY, Edwin Chan in LOS ANGELES, Isabel Reynolds in TOKYO, Editing by Mark Bendeich)

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