Life has not been quite what it was for Sun Microsystems, one of Silicon Valley's most venerable firms. Sun's version of the Unix operating system, Solaris, has been widely popular. Its muscular workstations and now, an innovative "thin client" network computer, has at times been some of the most exciting kit around.

And Sun came up with Java, the computer language and mini platform that transformed the internet. But the company that famously claimed to have put the "dot" in dotcom also tumbled when its huge market of internet-based companies took a dive, and Sun (which originally stood for Stanford University Network) has had hard going since.

On one front, it has been challenged by cheap and powerful desktop computers that have made its high margin workstations less irrelevant.

Then, Linux took no prisoners as the open-source version of Unix displaced proprietary operating systems like Solaris - which is now open source as well.

Finally, the company's strategy has been fuzzy, and its share price has largely remained flat.

The latter is a criticism that annoys chief executive and co-founder Scott McNealy, who points out the company is cash-rich, has no debt and gross profit margins of around 42 per cent.

However, at their recent analyst meeting in San Francisco, one exasperated analyst stated pointedly that each year, the company promises growth and profit and fails to deliver.

So why should they believe Sun - which employs 160 at its Dublin software development centre - is on the rebound now?

McNealy and Sun executives point to a number of factors. First, following the move to open-source Solaris, which they hope will seed the market for further Sun hardware and software products, the company has shipped more Solaris licences in the past year than in the rest of the company's history, says Jim McHugh, director of software portfolio strategy, speaking at Sun's offices overlooking San Francisco Bay.

He is upbeat about the move to open-source Solaris and to give away other software: "It's Sun returning to what Sun started off as, but it's a huge step. It changes the way we develop software and how our customers roll out software."

Sun also has a new line of servers based on a new Ultrasparc T-1 chip, an innovative design that runs faster at cooler temperatures.

The chip is now the centrepiece of new server lines with benchmarked performance two to four times faster than the competition, and a low-energy demand as well - the first "green" server if you will.

Then, they've open sourced the actual chip. Why?

"We want to encourage third-party developers who will take the architecture and modify the design to suit specific markets," says Fadi Azhari, director of outbound marketing. So far, interest in the new Sunfire and Galaxy servers seems good and reviews are generally excellent.

"It's given us a beachhead to win back customers," he says.

With the purchase of StorageTek, Sun has bridged one of its product gaps and moved firmly into the storage market to offer complete solutions, says Douglas Murray, executive director of global alliances.

And in two interesting but less tangible moves, Sun has formed a partnership with Google that has sparked wide interest, and has also moved into "utility computing", offering internet-accessible grid computing power and storage at very low cost.

"Plug in and use it," says Aisling McRunnels, an Irishwoman who is Sun's senior director of utility marketing.

Is all this enough to make Sun rise again? The share price has been steadily rising this year and some shrewd analysts think so.

But it will be months before the financial evidence will reveal if McNealy's "iPod moments" have paid off.