Bringing harmony to heterogeneity: the operations systems computing architecture

The operations systems computing architecture (OSCA), developed to promote the interoperability of large-scale software products, consisting of large numbers of programs, transactions, and databases, is described. OSCA contains three logical layers: a corporate data layer, a processing layer and a user layer. Each layer is made up of one or more well-defined deliverable, functional units called building blocks. A communications software fabric knits these building blocks together. Each of the three layers are described, along with the communications software fabric. A building block is defined, and the principles to which an OSCA building block adheres are listed. A discussion of the concept of the contract that specifies the interfaces among building blocks is included