Secure operating system
This artical is for Operating Systems which have achieved some credible form of security auditing, such as a B2 or A1 CSC-STD-001-83 "Department of Defense Trusted Computer System Evaluation Criteria," or Common Criteria certification.
For Security focused operating systems which do not necessarily have a certification, but which are aimed at security, see the appropriate article.
Solaris is a Unix variant created by Sun Microsystems. Solaris itself is not inherantly security-focused.
Solaris is, as of this edit on May 27, 2004, still maintained. It is a commercial Unix system.
Trusted Solaris is a security-focused version of the Solaris operating system. Aimed primarily at the government computing sector, Trusted Solaris adds detailed auditing of all tasks, pluggable authentication, mandatory access control, additional physical authentication devices, and fine-grained access control. Versions of Trusted Solaris through version 8 are Common Criteria certified.