The world-famous garage that spawned Silicon Valley has become a national historic landmark, a designation recognizing the place where Hewlett-Packard was founded nearly 70 years ago.Thursday, HP said the Palo Alto property - consisting of a two-story house, garage and shed - where co-founders Bill Hewlett and Dave Packard worked and lived was listed on the National Register of Historic Places by the National Park Service.

The garage in the rear of the Craftsman-style house at 367 Addison Ave. is where Hewlett and Packard set up shop in 1938, developing their first product, an audio oscillator. (Walt Disney Co. used the oscillators to improve the sound quality in the 1940 animated movie "Fantasia.") Hewlett lived in a

"The significance of the garage and the house is more associated with the entrepreneurial spirit in which it was developed," said Paul Lusignan, a historian with the National Register of Historic Places in Washington. "If you look at the history of HP, there are probably better buildings that represent its

The house, too, has significance for the company. Packard and his wife, Lucile, lived on the ground floor, while their landlady, Ione Spencer, lived in the flat upstairs. Lucile Packard did the company's books on a dining table, and Bill and Dave used the Wedgewood stove to bake the paint on the oscillators. HP quickly outgrew the garage and moved to 481 Page Mill Road in 1940.

The garage was designated a California registered landmark in 1987.To become a state and national landmark, buildings must be preserved to closely resemble their original state.Historians praised HP's restoration job, which was painstakingly detailed, down to the old coffee cans on the garage workbench and the vintage Fiesta dinnerware in the Packards' former flat. Old paint chips were used to determine the shade of forest green for the trim for the cedar-shingled house, and Douglas fir, like the original, was used to repair damage in the garage.

"There was such good photo documentation of this property that the house was very carefully taken back and reconstructed to its original appearance," said Cynthia Howse, a historian with the Office of Historic Preservation of the California Department of Parks and Recreation in Sacramento.The designation, an unusual one for an American corporate building, will not mean the property will be opened to tourists. Out of respect for the quiet, residential Palo Alto neighborhood, HP opens the garage and house only to visitors and special tours on certain occasions.As part of the restoration, HP replaced the solid fence that blocked the garage from view with a metal one that is easier for the curious visitors to peer through.