Microsoft Corp. and antitrust enforcers Thursday wrapped their examination of Microsoft Group Vice President Paul Maritz, but not before butting heads over documents government lawyers say could prove fatal to key portions of the software company's antitrust defence. Following an early morning court order that compelled their release, Microsoft surrendered to the Justice Department e-mails and a spreadsheet detailing how more than 1,900 operating system files were divided between the company's Internet Explorer browser and the rest of the Windows 98 software package. To date, the company has maintained the IE and Windows are inseparable, and repeatedly challenged government witnesses to say where one starts and the other begins. In insisting what the Justice Department calls two products are one, Microsoft says it can avoid liability under federal antitrust law, which bans monopolists from forcing customers to take one product as a condition of taking another. That assertion now appears in danger. Judge Thomas Penfield Jackson has Microsoft's own study showing that, of 1,903 software files, 690 deal only with Web browsing. In addition, 1,061 are shared by both the browser and the operating system, and 152 deal with the operating system alone. Government officials were upbeat over release of the data. "The code that provides browsing functions alone has been welded into the operating system," government lead attorney David Boies said. "I think that's very significant for our own tying claim." Microsoft officials downplayed the new data, as well as their own fierce resistance to their release. Spokesman Mark Murray said the data helped the company, since it showed Microsoft had integrated the browser into the operating system. Company lawyer John Warden, meanwhile, nearly concluded examination of Microsoft Group Vice President Paul Maritz. Warden probed Maritz with a series of questions designed to portray the emergent Linux operating system as a serious threat to Microsoft's estimated 95-percent market share in PC operating systems. Company lawyers insist that threat is among the best evidence that it has no monopoly over PC operating systems. Maritz told the judge that a flurry of new applications and new vendors supporting Linux meant that relatively unsophisticated consumers would soon being using the operating system. As a result, he said, Microsoft would have to work diligently to keep pace with the market. Microsoft produced a half-dozen magazine and newspaper articles to support its contention. Later in the afternoon, Boies entered into evidence an e-mail message in which Microsoft executives discussed withholding a version of its Office software suite from Apple Computer Inc. if the company did not comply with its agreement to distribute Microsoft's Internet Explorer browser. The April, 1998, e-mail followed by months a now-famous deal in which Microsoft sparred with the company over patents Apple said it had infringed. Maritz earlier testified his company agreed to keep producing the critically important software for Apple in exchange for its abandonment of the patent claims and promotion of IE. They finally struck a deal in the summer of 1997. Boies asked Maritz why Microsoft was continuing to use Office as a "club" months after the company had supposedly abandoned those threats. Maritz replied that since Apple was failing to live up to its part of the bargain Microsoft had to weigh renewing the threats. Take me to the DoJ/Microsoft page.