The security model is the cornerstone for developing the security operating system, while the formal method provides high level assurance for the understanding of the security model accurately.

安全模型是安全系统开发的基石，而形式化方法则为准确理解安全模型提供了高保障依据。

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We let the guys at Amazon worry about the security, maintenance and operating system upgrades.

FORBES: Amazon's EC2...Almost As Promising As Cliff Lee

SELinux includes security enhancements to the operating system that can enforce the separation of information based on the confidentiality and integrity requirements.

CNN: Sci-Tech - PGP working with NSA on Security Enhanced Linux

The company will continue to deliver free security fixes for the operating system beyond this cutoff date, however maintenance updates will require the purchase of extended support from Microsoft.

ENGADGET: Microsoft extends free Windows Server 2008 support through January 15th, 2015