This book provides a sound foundation for software architects who need to understand the potential impacts of moving to cloud computing. Though the book tends to focus on the public cloud, where information technology (IT) uses the services of a third-party supplier, rather than the private cloud, where IT internally provides cloud computing within its own data center, Shroff does not ignore the private cloud and readers can expect a mix of the two. This approach is appropriate because it gives software architects insight into what should move to the public cloud and what should remain in a private cloud.

The book consists of six parts. Part 1, on computing platforms, first provides a retrospective on architectures, including mainframe and client-server. Shroff then discusses the Internet as a platform, software as a service (SaaS) and cloud computing, and Dev 2.0, a nascent architecture where potential end users can participate in application development. This section starts the book’s trend of discussing a mix of existing enterprise application development architectures, along with Web-based architectures and the emerging Dev 2.0 platform.

Part 2 examines private cloud computing architectures, notably using the Amazon Elastic Compute Cloud (EC2) to illustrate infrastructure as a service (IaaS) and the Google App Engine (GAE) to illustrate platform as a service (PaaS). This part also includes a valuable chapter on cloud computing economics that clearly illustrates why cloud computing can be beneficial.

Part 3 dives into cloud technologies, covering Web services (simple object access protocol (SOAP) and representational state transfer (REST), Ajax, and Extensible Markup Language (XML)) and mashups, as well as virtualization technology and multi-tenant software.

Part 4 explores the richness of cloud development. One chapter, on data in the cloud, discusses relational databases and cloud file systems. BigTable, a distributed structured storage system built upon the Google File System (GFS), and HBase, which is based on the Hadoop Distributed File System (HDFS), receive particular attention. A second chapter covers Google’s MapReduce, a programming model that emphasizes parallel computing. The final chapter in this part goes into more depth on Dev 2.0, using Salesforce.com’s Force.com platform as one example.

Part 5 reviews the fundamentals of enterprise software architectures. One chapter covers package software, including enterprise resource planning, supply chain management, and customer relationship management. One chapter discusses custom enterprise applications, including a discussion of business logic and rule-based computing. There is also a chapter on workflow and business processes, including workflow engines.

The final part, on enterprise cloud computing, brings everything together. One chapter is on the enterprise cloud computing ecosystem, which includes a well-designed graphic that encapsulates the ecosystem for both a public and a private cloud. In this case, the graphic is worth the proverbial thousand words. The book ends with a roadmap for enterprise cloud computing that describes a mix of private and public cloud computing.

Because of its focus on software architects, the book does not delve deeply into compliance, security, and responsibility--the business issues that a chief information officer (CIO) needs to address when using public cloud computing services. For example, an enterprise might require strict service levels. How can these be guaranteed? Although this lack of discussion does not diminish the book’s intended purpose, readers should be aware that this aspect of enterprise cloud computing isn’t covered.