The Solution: Component Software

Object-oriented programming has long been advanced as a solution to the problems at hand. However, while object-oriented programming is powerful, it has yet to reach its full potential because no standard framework exists through which software objects created by different vendors can interact with one another within the same address space, much less across address spaces, and across network and computer architecture boundaries. The major result of the object-oriented programming revolution has been the production of "islands of objects" that can't talk to one another across the sea of application boundaries in a meaningful way.

The solution is a system in which application developers create reusable software components. A component is a reusable piece of software in binary form that can be plugged into other components from other vendors with relatively little effort. For example, a component might be a spell checking feature sold by one vendor that can be plugged into several different word processing applications from multiple vendors. It might be a math engine optimized for computing fractals. Or it might be a specialized transaction monitor that can control the interaction of a number of other components (including service providers beyond traditional database servers). Software components must adhere to a binary external standard, but their internal implementation is completely unconstrained. They can be built using procedural languages as well as object-oriented languages and frameworks, although the latter provide many advantages in the component software world.

Software component objects are much like integrated circuit (IC) components, and component software is the integrated circuit of tomorrow. The software industry today is very much where the hardware industry was 20 years ago. At that time, vendors learned how to shrink transistors and put them into a package so that no one ever had to figure out how to build a particular discrete function—an NAND gate for example—ever again. Such functions were made into an integrated circuit, a neat package that designers could conveniently buy and design around. As the hardware functions got more complex, the ICs were integrated to make a board of chips to provide more complex functionality and increased capability. As integrated circuits got smaller yet provided more functionality, boards of chips became just bigger chips. So hardware technology now uses chips to build even bigger chips.

The software industry is at a point now where software developers have been busy building the software equivalent of discrete transistors—software routines—for a long time.

The Component Object Model enables software suppliers to package their functions into reusable software components in a fashion similar to the integrated circuit. What COM and its objects do is bring software into the world where an application developer no longer has to write a sorting algorithm, for example. A sorting algorithm can be packaged as a binary object and shipped into a marketplace of component objects. The developer who need a sorting algorithm just uses any sorting object of the required type without worrying about how the sort is implemented. The developer of the sorting object can avoid the hassles and intellectual property concerns of source-code licensing, and devote total energy to providing the best possible binary version of the sorting algorithm. Moreover, the developer can take advantage of COM's ability to provide easy extensibility and innovation beyond standard services as well as robust support for versioning of components, so that a new component works perfectly with software clients expecting to use a previous version.

As with hardware developers and the integrated circuit, applications developers now do not have to worry about how to build that function; they can simply purchase that function. The situation is much the same as when you buy an integrated circuit today: You don't buy the sources to the IC and rebuild the IC yourself. COM allows you to simply buy the software component, just as you would buy an integrated circuit. The component is compatible with anything you "plug" it into.

By enabling the development of component software, COM provides a much more productive way to design, build, sell, use, and reuse software. Component software has significant implications for software vendors, users, and corporations:

Application developers are enabled to build and distribute applications more easily than ever before. Component objects provide both scalability from single processes to enterprise networks and modularity for code reuse. In addition, developers can attain higher productivity because they can learn one object system for many platforms.
Vendors are provided with a single model for interacting with other applications and the distributed computing environment. While component software can readily be added to existing applications without fundamental rewriting, it also provides the opportunity to modularize applications and to incrementally replace system capabilities where appropriate. The advent of component software will help create more diverse market segments and niches for small, medium, and large vendors.
End-users will see a much greater range of software choices, coupled with better productivity. Users will have access to hundreds of objects across client and server platforms—objects that were previously developed by independent software vendors (ISVs) and corporations. In addition, as users see the possibilities of component software, demand is likely to increase for specialized components they can purchase at a local software retail outlet and plug into applications.
Corporations benefit from lower costs for corporate computing, helping IS departments work more efficiently, and enabling corporate computer users to be more productive. IS developers will spend less time developing general purpose software components and more time developing "glue" components to create business-specific solutions. Existing applications do not need to be rewritten to take advantage of a component architecture. Instead, corporate developers can create object-based "wrappers" that encapsulate the legacy application and make its operations and data available as an object to other software components in the network.

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