The five-story underground parking garage Microsoft is building on its corporate campus is drawing plenty of attention due to its massive size Xerox has its legendary PARC labs. Now Microsoft has its famous parking lot.Work has just begun on a massive underground parking garage at Microsoft’s Redmond, Washington, headquarters, a structure that should alleviate current parking headaches on the corporate campus.The buzz around this low-tech project at the high-tech giant’s headquarters is growing locally since a television news crew went out to gawk at the hole in the earth. While hardly comparable to Boston’s big dig project, the local news at least seems ready to add this one to the record books. One report called this the second largest underground garage in the western hemisphere, but Microsoft spokesman Lou Gellos said he had no idea where that factoid came from and couldn’t confirm it. The garage will be around 1,440 feet (439 meters) long and 540 feet wide. In American football terms, that’s four fields long and one and a half wide. It will have four floors of parking, all underground. Up to 5,000 cars will fit in the garage. Four additional office buildings and a green space will take up the area above ground.The garage and new buildings are part of a $1.3 billion campus expansion that Microsoft announced last February. At that time, expansion planners figured the garage would be above ground but as they got further into the design process, they came up with the idea of making it subterranean and placing additional offices and common areas above, said Gellos.The digging, which started the first week of June, will take until about October and the garage should be ready for use in the second half of next year. In another effort to reduce parking problems on campus, Microsoft has long offered employees free bus passes. It also has a fleet of Toyota Prius cars to shuttle workers around campus. Technology Industry