SAN FRANCISCO (AP) _ The FBI on Tuesday launched operation ``Cyber Strike,'' a crackdown on computer software pirates who have cost game and program makers millions of dollars in losses.

Agents searched homes and businesses in eight cities and confiscated computers; no immediate arrests were expected.

Software pirates have hit major players such as Microsoft Corp., Sony Computer Entertainment and gamemakers Sega of America Inc. and Nintendo of America. In all, the FBI listed nine companies as piracy victims.

Nintendo has lost ``millions and millions and millions upon millions'' to pirates, especially from its Donkey Kong and Mario series games, said company spokesman Perrin Kaplan from Redmond, Wash.

``Whatever's popular _ that's what they want,'' Kaplan said.

The FBI said it was seizing computer hardware, documents and records in Atlanta; Columbus, Ohio; Miami; Oklahoma City; Des Moines, Iowa; Pittsburgh; and San Leandro and Cedar Ridge, Calif.

Some software pirates do it for fun. Others are making a substantial amount of money from selling bootleg software, software publishers say.

Pirates obtain legitimate software and manage to copy it despite safeguards against copying. They make it available to other computer users through Internet web sites or computer bulletin boards.

They give it away, trade for other software, or sell it _ asking for a credit card number or payment in advance. Often, it is sold for substantially less than market value _ anywhere from about $50 to hundreds of dollars.

George Grotz, FBI spokesman in San Francisco, said the probe uncovered a ``significant number'' of what are known as pirate bulletin boards.

``It's a rather complex `word-of-mouth vouch-for' system,'' Grotz said.

Often, illegal copies are available the day legitimate software is released, if not before.

``The Internet has just opened up whole new venues,'' said Chris Berg, director of security and safety for Sega in Redwood City, Calif. ``It's significantly added to the problems that we have.''

Software piracy cost the industry an estimated $13.1 billion worldwide in 1995, according to a survey by the Business Software Alliance and Software Publishers Association. In the United States, the losses were $2.9 billion.

``It is absolutely a daunting challenge,'' said Diane Smiroldo, a spokeswoman for the Washington-based Business Software Alliance.

Most companies are reluctant to say how much they've lost.

Microsoft spokeswoman Karen Porter would only say that the problem has cost the Redmond, Wash., software giant ``millions.''

Sega's Berg said the problem is substantial enough that the company has had as many as 12 people working with the FBI. ``It's enough of a problem for us to put resources to chase it,'' Berg said.

The other software companies listed by the FBI as piracy victims are Autodesk Corp., Adobe Systems Inc., Intuit Corp,. Symantec Corp. and Novell Inc.