Symantec CEO John Thompson Tuesday found himself again defending his company's planned purchase of Veritas amid continued investor concerns about the company's strategy and fears of Microsoft's looming presence in the security market.

Addressing reporters during a roundtable discussion at the RSA Conference, Thompson rebutted suggestions that the Veritas merger is a defensive move driven by Microsoft's growing ambitions in the security market. "I couldn't care less about what Microsoft does" in the security market, Thompson said.

Instead, he said, Symantec's purchase needs to be viewed as a strategic expansion of its capabilities in response to customer needs for integrated data integrity and data availability technologies.

"We are determined to get this done; regardless of how the equity market responds, we are going ahead with it," Thompson said.

He also dismissed suggestions that Microsoft's move to integrate its spyware tool for free into future Windows versions would hurt Symantec's own spyware products, which the company touted as part of its antivirus suite Tuesday.

"We are convinced that we can whip Microsoft in the market," he said, adding that Symantec would not be "whining in Washington" about Microsoft's moves.

Several large users of Symantec's products expressed support for the company's technology strategy during the discussion.

There is a growing need for security technologies that can help companies enable better integrity and availability of stored data, said Tom Jones, director of security for California's Health and Human Services Department. As an organization that handles more than 150,000 customers in a regulated industry, the agency faces a huge challenge in protecting the more than 300TB of data it currently stores, Jones said.

"Our protection requirements are all focused around HIPAA," Jones said. Using point products to protect data won't be good enough in the long term, he said.

Chevron Texaco has begun taking a more integrated view of the operational risks posed by its information technologies, said Richard Jackson, the company's chief information protection officer. Chevron Texaco's IT infrastructure includes more than 40,000 desktops, 8,000 laptops, 750 servers and over 500TB of data stored around the world.

"We are integrating information risk components into a single-risk entity" to enable better security of this data, Jackson said. "Decision quality is central, so integrity of data is crucial," he said.

Those comments come at a time when Symantec, the industry's largest pure-play security vendor, is under growing pressure from investors to justify its planned purchase of Veritas, a slower-growing vendor of storage technologies. Since the deal was announced, the company's stock has lost more than one quarter of its value.

Adding to that pressure is Microsoft's looming shadow in the security market. In the inaugural keynote at the RSA Conference Tuesday, Microsoft Chairman Bill Gates laid out a strategy that calls for Microsoft to offer antivirus, antispyware and firewall technologies in an effort to move deep into security market, which is currently dominated by companies like Symantec.