92 ComputerAnnounced in July 2000, .NET,Microsoft’s platform forXML-based Web services, iscurrently undergoing a succes-sion of beta versions for a pro-jected release late this year or early in2002. .NET has a central role in Micro-soft’s strategy to integrate the Internet,Web services, building block services,numerous tools for developers, andmany other features.Curiously though, this next generationof software hasn’t grabbed the comput-ing world’s attention as Java did in itsheyday. Yet, in many respects, .NET is amore important phenomenon. The busi-ness press, for its part, hasn’t missed thetechnology’s significance. Both BusinessWeek (cover story, 30 Oct. 2000) andThe Economist (January 2001) havedevoted major coverage to .NET.A FAILURE OR THE FUTURE?Perhaps it is .NET’s breadth of cover-age that has puzzled some technicalobservers and made them wonderwhether there was anything beyond thehype. One observer who doesn’t think sois John Dvorak, who in his November2000 PC Magazine column wrote that.NET is “surrounded by too many buzz-words and generalities to be under-standable. I’m not sure the companyknows what .NET is, or whether any-body does. It has the onerous smell offailure about it already.” The basis for this indictment seems tobe a Microsoft public relations documentdescribing an exciting future in which—thanks to .NET—from your Web-connected bike at the gym, you can effort-lessly change both your evening’s restau-rant reservation and babysitter whilepedaling away without missing a beat. Ifthe aim is to set lofty ideals for the nextgeneration, this example is admittedlyunderwhelming, but since when are tech-nical journalists supposed to judge newtechnologies by press releases?Others have been more perspicacious.For example, the Patricia Seybold Groupwrote that “.NET is a leading exampleof what we believe will be the dominantarchitectural model for the third genera-tion of Internet applications” and that ithas “ominous implications for a largenumber of Microsoft competitors.”WHAT .NET ISN’TIn describing .NET, it’s useful first topoint out what it is not. It’s neither anoperating system nor a programming lan-guage. Microsoft operating systems con-tinue their own evolution—Windows2000, Me, XP, CE for embedded devices—although you can expect more .NET bitsto filter down into the base OS. As for pro-gramming languages, .NET has intro-duced a new one, C# (C-sharp), but it’s notthe focus of the technology—it’s simply themeans to an end, the basic notation forprogramming the .NET runtime.Technically, C# looks very much likeJava, with extensions similar to mecha-nisms found in Delphi and Microsoft’sVisual J++. These extensions include“properties”—an attempt to remedyJava’s information-hiding deficiencies—and an event-driven programming modelusing the notion of “delegates”—objectwrappers around functions—that areappropriate for graphical user interfaceand Web applications. While it is likely to become a seriouscompetitor to Java, C# is not an attemptto replace all existing languages. In fact,Microsoft’s own investment in VisualBasic (recent estimate: 6 million devel-opers) and C++ would make such a goalself-defeating.Instead, a distinctive characteristic of.NET is its language neutrality. In additionto Microsoft-supported languages, .NETis open to many others including Cobol,Eiffel, Fortran, Perl, Python, Smalltalk,and a host of research languages from MLto Haskell and Oberon. Unlike others inthe industry, Microsoft isn’t trying to con-vert the world to a new language. .NET ARCHITECTURESo what is .NET? A general definitionmight be: “An open language platformfor enterprise and Web development.”The aim is to provide an abstractmachine for professional developers, cov-ering both traditional IT—client-server,n-tier—and Web-oriented applications.Figure 1 shows the six layers of the plat-form’s overall structure. Web services. The top layer provides.NET users—persons and companies—with Web services for e-commerce andbusiness-to-business applications..NET Is ComingBertrand Meyer, Interactive Software EngineeringSOFTWARE TECHNOLOGIES.NET, an open language enterprise andWeb development platform, has thepotential to dominate the computingindustry for years to come. This month’s contribution to Software Technologies discusses the emergence ofMicrosoft’s .NET platform for Web services. While it is significantly longer than thestandard for the department, I argued that the additional length is warranted becausethis technology promises to have significant, wide-ranging effects on software devel-opment, and the editorial staff concurred. We all hope that readers will be as inter-ested in this development as we are.Michael Lutz, Area EditorFrameworks and libraries. A set offrameworks and libraries provides themost immediately attractive aspect fordevelopers. These include ASP.NET, activeserver pages for developing smart Websites and services; ADO.NET, an XML-based improvement to ActiveX DataObjects, for databases and object-rela-tional processing; and Windows Formsfor graphics. Altogether, .NET containsthousands of reusable components.Interchange standards. XML-basedinterchange standards serve as a plat-form-independent means of exchangingobjects. The most important are SOAP(simple object access protocol), anincreasingly popular way to encodeobjects, and WSDL (Web ServicesDescription Language). Development environment. The newVisual Studio.Net provides the tool ofmost direct use to developers: A commonsoftware development environment offer-ing facilities for development, compila-tion, browsing, and debugging shared bymany languages. This environment, anoutgrowth of Visual Studio extendedwith an application programming inter-face, not only supports Microsoft-imple-mented languages such as Visual C++,Visual Basic, and C# but also allowsthird-party vendors to plug in tools andcompilers for other languages.Component model. Before .NET therewere already three major contenders forleadership in the field of models and stan-dards for component-based development:Corba from the Object ManagementGroup, J2EE from Sun, and Microsoft’sCOM. .NET brings in one more model,based on object-oriented ideas: With.NET you can build “assemblies,” eachconsisting of a number of classes withwell-defined interfaces. The model is quitedifferent from COM, although it providesa transition path; its major attractions areits
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