In technology markets, playing catch-up is a bruising, costly and often futile game, even for corporate giants.

Nokia and Hewlett-Packard, in different ways, both provided vivid evidence of that challenge on Wednesday. In a memo to Nokia employees, Stephen Elop, the new chief executive, compared its predicament in trying to catch up to Apple and Google in smartphones to that of a man, in a story, who was standing on a burning oil rig at sea.

?The man was standing upon a ?burning platform,? and he needed to make a choice,? Elop wrote in the memo, which was widely circulated on the Internet. ?He decided to jump.?

In the memo, Elop went on to say that Nokia, too, had to jump, metaphorically ? take bold action to make up for lost ground.

Meanwhile, in San Francisco, HP, the largest personal computer maker, took its own leap on Wednesday. The company announced that it would introduce a new tablet, the Touchpad, in an effort to chase Apple and its iPad. HP also introduced two new smartphones, entering another market in which it has lagged.

But Nokia and HP ? tech giants though they are ? face long odds in catching up with competitors that have a head start in a rapidly changing landscape. It?s hard to do that in any business, but especially so in technology markets. ?It?s possible to catch up, but it?s very difficult,? observed Mark Anderson, chief executive of the Strategic News Service, a technology newsletter. ?It almost never works.?

History offers a handful of successful catch-up stories. For example, IBM, the mainframe behemoth, trailed the leaders in the new markets for minicomputers and then personal computers, but later caught up. And Microsoft was a latecomer to Internet browsing software, yet eventually became the market leader.