Per the
Computing Dictionary:
- reliability definition
system
An attribute of any system that consistently produces the same results, preferably meeting or exceeding its specifications. The term may be qualified, e.g software reliability, reliable communication.
- security definition
security
Protection against unauthorized access to, or alteration of, information and system resources including CPUs, storage devices, and programs....
The security definition continues with additional inclusions, such as confidentiality, authentication, non-repudiation and more; I will leave it to you to do your own research at
http://dictionary.reference.com if you are interested in further definition.
As for OpenBSD, let us look at this simple Venn Diagram, linked from Wikipedia for expediency:
Assume that the set on the left is Reliability, and the set on the right is Security. The union of the two is where Reliability and Security are the same. In software terms, this is often areas where coding errors impact both. The effort to eliminate those problems is described as a drive for
code correctness.
OpenBSD's security goals are described in
www.openbsd.org/security.html, where the Project's Audit program is described. The text discusses the effort to establish and maintain code correctness:
"We are not so much looking for security holes, as we are looking for basic software bugs....During our ongoing auditing process we find many bugs, and endeavor to fix them even though exploitability is not proven. We fix the bug, and we move on to find other bugs to fix. We have fixed many simple and obvious careless programming errors in code and only months later discovered that the problems were in fact exploitable."
In summary, then, while the size of the union of the two sets is non-deterministic, I believe it is quite large, and I appreciate the Project's effort to strive for correctness as a cornerstone of both proactive security and reliability.