By JOHN MARKOFF

UPERTINO, Calif., June 7 — Anyone looking for the next big thing in Silicon Valley should stop here at Layne Holt's garage.

Mr. Holt and his business partner, John Furrier, both software engineers, have started a company with a shoestring budget and an ambitious target: the cable and phone companies that currently hold a near-monopoly on high-speed access for the "last mile" between the Internet and the home.