Open systems, through the use of public, consensus based specifications or standards, are focussed on achieving the interoperability between, and the portability of, components. In accommodating standards, open systems promise the advantages of plug-n-play technology, rapid prototyping and component re-use, while at the same time preventing system integration misfits, short system lifespan and difficulty in maintenance. In the development of open systems, it has been recognised that the specification and standardisation of interfaces, not components, is of critical importance to realising these advantages. Due to the critical role of interfaces in open systems, the quality of the interface specifications used to engineer the interfaces is fundamental to the fulfilment of the promises of open systems.The authors contend that since current specifications and standards are deficient, then open complex computer systems, built using these specifications and standards, will indeed be no silver bullet. The authors present several ways forward, based on the inter-relationships between components, so that in the future the promises of open complex computer systems may still be fulfilled.