COM+ is an advanced COM run-time environment that provides prefabricated solutions to many of the generic infrastructural problems faced by enterprise application designers, particularly the infrastructural problems of the middle, business tier in the three-tier model. If you think of the product as "Microsoft Enterprise Application Prefabricated Functionality Toolkit," you'll have the right mental model.
COM+ is an integrated part of Windows 2000. It would be premature to say anything in print about a shipping schedule for Windows 2000, but there's a good chance it will be after this book appears on bookstore shelves.
COM+ provides two significant enhancements to COM. First, it is version 3 of Microsoft Transaction Server (MTS), updated and integrated into the existing portions of COM to provide a seamless whole. MTS, which first shipped in the spring of 1997, was Microsoft's first attempt to provide any type of enterprise infrastructure as a product.
COM+ enhances and upgrades the following MTS services:
Transaction Services Transactions are a mechanism for ensuring data integrity in a distributed system, even in the face of communication or machine failure. The transaction services of COM+ provide an easy way for COM objects to create, use, and vote on the outcomes of transactions
Security Services Essentially all enterprise applications care about security. They need to make sure that only authorized users are allowed to perform important operations. Writing security code using the raw Windows NT security mechanism was and continues to be a nightmare. COM+'s security services provide an easy way to specify security administratively, without writing any code at all. These services also provide a much easier way to write programmatic security logic for situations too complex for the administrative mechanism to handle
Synchronization Services Architects of distributed systems need to protect certain critical portions of their components against the possibility of concurrent access by multiple threads. Writing code to do this takes a long time, costs a lot of money, and is extremely difficult to get right. The synchronization services of COM+ provide an easy way to specify a component's synchronization requirements administratively without the need for code. These services also provide an easier way to write programmatic synchronization logic for situations too complex for the administrative mechanism to handle.
COM+ is version 3 of Microsoft Transaction Server, updated and integrated into the existing portions of COM to provide a seamless whole.
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