Distributed

Early sections introduce ADSI, which allows programmers access to a variety of directory services, including Windows NT 4/5 (Windows NT 5 is now known as Windows 2000), Lightweight Directory Access Protocol (LDAP), Netware 3.x/4.x, and Domain Naming System (DNS). (In theory, with a single Windows NT box and IIS, an organization could administer resources remotely on any of these diverse platforms.) Early sample programs look at getting to domain information. Then it's on to querying users, changing passwords, and then managing groups and security. In one sample, the author provides a Web-based, remote user manager to demonstrate the use of the ADSI User object (which gives access to no less than 47 different user properties). Though all samples use VBScript and Active Server Pages (ASPs) for Web-based administration, ADSI objects will also work with C++ and Java.

Later sections look at the remote administration of services and files and provide background material on the LDAP, which is the foundation of ADSI (and the Active Directory in Windows NT 5). Several concise appendices on ADSI objects and error codes round out this efficiently presented guide, which is sure to be valuable to any Windows system programmer considering Web-based administration. --Richard Dragan

An indication of the slow pace can be found in the time required to reach the discussion of IUnknown, the interface that every COM class must implement. This book may not mention the interface until page 80, however, the preceding sections provide a rich background on OLE, COM, and ancillary information on multitiered systems as well as the process of setting up a testbed.

The optimistically proposed testbed relies on Windows 2000 Professional, Windows 2000 Domain controller, and Windows NT. Luckily, the majority of the examples in the book do not require such a complex setup to be run. However, in part 3, Windows DNA, the described testbed, serves as an optimal solution.

Advancing from the slow introduction to the very involved discussions in part 3, the book spans COM, COM+, Distributed COM (DCOM), and Active Template Library (ATL), with threading, Microsoft Message Queue Server, security, and other design issues addressed where appropriate.

This book also differentiates itself by depending on two programming languages to demonstrate COM implementations. Although the author seems to prefer, and at times champion, Visual Basic COM programming, C++ programmers will be happy to note that the majority of the code examples are in C++. Unfortunately, Java programmers get short shrift--there's almost no coverage of Visual J++ COM.

For comprehensive, thorough explanations with useful code using COM, though, this book is hard to beat. --John Keogh

Topics covered: History of COM, OLE, overview of COM, DCOM and COM+, distributed systems architecture, creating a testbed, classes and interfaces, implementing a COM class in C++, implementing a COM class in Visual Basic, introduction to COM servers, Inprocess servers, class factories, creating a server, Active Template Library, Microsoft IDL, out of process (exe) servers, going from COM to DCOM, programming for DCOM, overview of DCOM, Automation and Visual Basic, collections, error handling and debugging, multithreading in COM, COM+, developing for COM+ in Visual Basic, developing for COM+ in Visual C++, threading issues in COM+, COM+ and Windows 2000 Security, introduction to SQL Server, ActiveX Data Objects (ADO), using COM+ in the middle tier, transactions, COM+, and Microsoft Distributed Transaction Coordinator, Web application programming with COM+, Active Server Pages and COM+, MSMQ (nice discussion), events, scalability, clustering, load balancing, object pooling.

In addition to the specific guidance offered on how to keep SAP R/3 running smoothly, this book is also designed to serve as a preparatory text for SAP's Certified Technical Consultant test. For example, each chapter ends with review questions similar to those that may appear on the test. You can try out the knowledge you've gleaned with the timed test engine on the bundled CD-ROM. Sarah L. Roberts-Witt

Early chapters look at the rich design possibilities of MSMQ, including reliable asynchronous communications (where parties do not have to be online together) and today's three-tiered architectures (where business rules are kept on the server). From this general perspective, Designing Applications with MSMQ moves to practical examples of an MSMQ program written two ways: through COM objects that work with tools, such as Visual Basic and Visual C++, and a more basic C API. Once a simple MSMQ program is created, the author shows how it can be enhanced, by making it asynchronous, for instance, for offline message delivery.

A tour of MSMQ's security features and support for transactions follows, including when and how to use Microsoft Transaction Server (MTS) with MSMQ. (Besides an introduction to these Microsoft technologies, the author does a fine job of explaining transaction processing in general.) The included appendix features a full reference on all nine MSMQ COM objects, plus the MSMQ C API. --Richard Dragan