Parallel Evolution of Parallel Processors [Book Reviews]

ment of an architecture for cliendserver business applications over a “global LAN” that introduces an analysis and design method for distributed systems. Unfortunately, the text doesn’t explain what this so-called global LAN is constructed of or how it works. The architecture described makes a virtue of separating data from applications-which is opposite the direction where most modern solutions are headed. The authors also describe distributed computing at Eastman Kodak, mainly based on experiences in beta testing of DECathena in an industrial setting. DECathena (described in more detail in Part 1) is the commercial version of Project Athena. Part 3 describes implementation and management strategies. T h e highlight of this part is the chapter that describes the products and strategies of vendors such as SunSoft, Hewlett-Packard, IBM, and Microsoft. There is an interesting discussion of Microsoft’s strategy for object linking and embedding (OLE) and Cairo, an object-oriented operating system allegedly based on a distributed object model. SunSoft’s strategy for the Distributed Object Environment (DOE) builds on the chapter on ONC+ in Part 1 , and in many ways it would have been logical to include this material in that part. Other chapters in this part describe management of migration and organizational issues. Finally, the four appendixes detail important topics predicted to influence distributed computing in the future, such as the OSF Distributed Management Environment and Object Management Group’s (OMG) Common Object Request Broker Architecture (Corba). It is unfortunate that the authors postponed this overview of the emerging distributed object standard until the appendixes. There are many products available that conform to the Corba standard, and it would be very interesting to read of developers’ and managers’ experiences in using them. Details of what is proposed by the OMG for the Common Object Services Specification and Corba2 would also be useful, as would be the recent standard for object-oriented databases (ODMG-93), which is omitted. The authors could have mentioned the International Organization for Standardization’s Olpen Distributed Processing draft framework here, as it has the widest scope of all distributed environment standards. In conclusion, this book contains several technical details about the various distributed environments and the experiences of network managers who plan and operate them. However, although the work is a rich source of reference material, some of the material is slightly dated. Moreover, the reader might find it difficult at times to reach firm conclusions about the costs or benefits of the various options. In the case of proprietary solutions it is difficult to determine what to develop, and in the case of prebuilt solutions it is difficult to foresee where the major vendors’ development strategies are headed. All of these problems reflect the rapidly evolving nature of the state of the art of distributedcomputing technology. I t would be possible to improve on this somewhat unsatisfactory aspect by including a concluding chapter that draws the various strands and arguments together. Such a chapter could take the form of a comparison framework detailing the features, costs, and benefits of the competing implementations, and manager and vendor strategies. Nevertheless, the book as it stands will be useful to professionals who need a starting point for investigating the ingredients of current distributed-computing solutions.