This volume contains the papers presented at the Second International
Work- ing Conference on Dependable Computing for Critical Applications,
sponsored by IFIP Working Group lOA and held in Tucson, Arizona on
February 18-20, 1991. In keeping with the first such conference on this
topic, which took place at the University of California, Santa Barbara
in 1989, this meeting was like- wise concerned with an important basic
question: Can we rely on Computers? In more precise terms, it addressed
various aspects of computer system de- pendability, a broad concept
defined as th'e trustworthiness of computer service such that reliance
can justifiably be placed on this service. Given that this term includes
attributes such as reliability, availability, safety, and security, it
is our hope that these papers will contribute to further integration of
these ideas in the context of critical applications. The program
consisted of 20 papers and three panel sessions. The papers were
selected from a total of 61 submissions at a November 1990 meeting of
the Program Committee in Ann Arbor, Michigan. We were very fortunate to
have a broad spectrum of interests represented, with papers in the final
program coming from seven different countries, representing work at
universities, corporations, and government agencies. The process was
greatly facilitated by the diligent work of the Program Committee and
the quality of reviews provided by outside referees. In addition to the
paper presentations, there were three panel sessions or- ganized to
examine particular topics in detail.