Hewlett-Packard, Dell and Lenovo are rolling out machines that give people access to basic functions like e-mail and a Web browser in 30 seconds or less. Asus, a Taiwanese company that is the world’s largest maker of the circuit boards at the center of every PC, has begun building faster-booting software into its entire product line.

Even Microsoft, whose bloated Windows software is often blamed for sluggish start times, has pledged to do its part in the next version of the operating system, saying on a company blog that “a very good system is one that boots in under 15 seconds.” Today only 35 percent of machines running the latest version of Windows, called Vista, boot in 30 seconds or less, the blog notes. (Apple Macintoshes tend to boot more quickly than comparable Windows machines but still feel glacially slow to most users.)

There is nothing new about frustration with start-up times, which can be many minutes. But the agitation seems more intense than in the pre-Internet days. Back then, people felt less urgency to log on to their solitary, unconnected machines. Now the destination is the vast world of the Web, and the computer industry says the fast-boot systems cater to an information-addicted society that is agitated by even a moment of downtime.

Yet it is a condition that the technology industry  with smartphones and other always-on gadgets  helped create, said Gary Small, a professor at the Semel Institute for Neuroscience and Human Behavior at the University of California, Los Angeles. “Our brains have become impatient with the boot-up process,” Dr. Small said. “We have been spoiled by the hand-held devices.”

PC makers are not merely out to ease our data anxieties with the new machines. They want to help themselves, too. The industry has grown so competitive, and profit margins so thin, that each company is looking for any advantage it can trumpet. Computer makers say the battle for boot-up bragging rights could resemble the auto industry’s race to shave tenths of a second from the time it takes a car to go from 0 to 60 miles an hour.