@techreport{TR-IC-04-06, number = {IC-04-06}, author = {Paulo Guerra and Fernando Castor Filho and Cec{\'{\i}}lia Mary F. Rubira}, title = {Specification of the Idealised Fault-Tolerant {C2} Component---Asynchronous Model}, month = {June}, year = {2004}, institution = {Institute of Computing, University of Campinas}, note = {In English, 26 pages. \par\selectlanguage{english}\textbf{Abstract} The concept of idealised fault-tolerant C2 component(iC2C) was introduced as a means for constructing dependable component-based software systems in the C2 architectural style out of existing software components. It is derived from the concept of idealised fault-tolerant component, which aims at providing a structuring for systems which minimizes the contribution of the fault-tolerance mechanisms to their overall complexity. The use of iC2Cs as architectural blocks from which a system is built simplifies the task of building component-based, dependable systems. In this work we present informal and formal specifications for the iC2C. The formal specification is based on a state-machine view of the iC2C which emphasizes the functioning of its internal protocol and makes it easy to specify and prove properties over it. Furthermore, we make some considerations relevant to the implementation of the iC2C. } }