There, at the Tysons Corner Marriott, was a large and impressive slice of Fairfax County '85: the chief executive officers of high tech, high finance and high employment -- from the firms that are making this county go boom.

By and large, they like what they see in Fairfax, and in each other: a pro-development attitude. More than anyplace else in the region, this is business country. Not even Montgomery County -- with the second-largest number of technology-oriented workers and firms -- is as independent of the federal government presence. The civil servant still lives here, but Uncle Sam doesn't own much property in Fairfax and hasn't been asked to look around. The county government courts business.

Still, there is a certain uneasiness among the business and county leaders. It is why they showed up in such impressive numbers for the meeting sponsored by the Fairfax County Chamber of Commerce, the county's Economic Development Authority and the Redevelopment and Housing Authority. The topic was upbeat enough: "New Partnerships for Growth." But the talk was down to earth -- the increasingly valuable earth of Fairfax, and who can afford housing on it anymore.

This might not tug at the heartstrings of anyone from less fortunate parts of the region or the country. But it's a serious concern -- and out of it may come some proposals that could mean still more business and jobs for Fairfax as well as the entire metropolitan area.

The comparison made by County Executive John F. Herrity served to hammer home an unsettling prospect. Herrity noted that he and other county leaders had visited Silicon Valley in California, where, in the aftermath of a development boom, three problems have loomed large: 1)secondary education, stung by the effects of Proposition 13 on budgets; 2)transportation, not keeping pace with the growth; and 3)housing, unaffordable for middle-management people, to say nothing of lower-income workers.

"We want to avoid in 10 years the Silicon Valley experience," said Herrity, noting that while the county government is not the "primary deliverer" of housing, it does stand ready to work with private industry.

Right now in Fairfax, with a vacancy rate of about 2 percent, housing prices high and the supply of apartments low, moderate-income employees are finding it increasingly difficult to live in the county. They're ending up in Stafford, Fauquier and Loudoun counties. According to the Greater Washington Research Center, Fairfax is home for about one- third of the workers in Fairfax County firms. John J. Castellani, chairman of the Redevelopment and Housing Authority, noted that unless government and business team up to do something clever soon, potential employers may locate elsewhere.

What to do? Try this, from Charles Gulledge, chairman of the Economic Development Authority: some form of company housing on a convenient tract, maybe built with tax-exempt financing and writeoffs and offered at affordable rents. A company also might form its own real estate assistance firm to help employees make payments. It could earmark funds for rent subsidies or mortgage buy- downs.

If this line of suggestions "sounds socialistic," said Gulledge, "believe it, they're not intended to be. . . . The future will not be the same. I remember when Social Security was brand new, when there was no company insurance, few pension plans, and employee stock options didn't exist, employee savings plans didn't exist, when overtime was heard about but not received, when there were no real health benefits, and death benefits didn't exist. . . . Now affordable housing is needed for everyone from young job-seekers to chief executives."

Walter D. Webdale, director of the county's department of Housing and Community Development, noted that once a firm does figure what it might be able to do and for how many, the county government can assist with rezoning, tax-exempt bonds for moderate-income housing and other financial assistance. "Call us and we'll work with you."

Therein lies something for all local governments to think about as this region's economy is restructured away from government employment toward firms that supply and service the government as well as other industries. Fairfax County's government has overcome the kind of self-consciousness about working with and for business that still may be hampering efforts elsewhere in the region. It's not a matter of "caving in" to big business or to willy-nilly development. If Greater Washington is becoming less and less Uncle Sam's "company town," then other companies can and should play a more important role.