.Net under the microscope

The ideal software platform is easy to define. It puts no barriers between a designer’s ideas and their implementation. Programming and debugging are efficient, and all essential services are provided in a consistent, logical and sensible fashion. Applications run where and when needed, automatically.

Listening to Microsoft it would be easy to believe that its .Net platform is the physical manifestation of this ideal platform. But while .Net is probably the closest the Redmond company has come to creating an environment for developers and users that adheres to a lot of the ideals, it isn’t quite perfection incarnate.

The original vision was that a .Net program would run on a .Net platform, regardless of what that platform was. Microsoft implied that .Net would work with other, non-Windows, systems. Surprisingly that hasn’t transpired, but now other software companies and developers are working to open .Net up.

At heart, .Net is based on the Common Language Infrastructure, a standard execution environment similar to the Java Virtual Machine. Under the CLI, an application program written in any of a number of languages -- ASP+, C++, C#, Visual Basic, Fortran -- can run on any of a number of operating systems, as long as the compiler produces the appropriate bytecode -- the Common Intermediate Language (CIL) -- and the program uses the acceptable data types and operations as defined in the Common Type System or CTS.

The CIL bytecodes are interpreted and turned into native binary at runtime by the Common Language Runtime (CLR) part of the CLI. Some of these portions of .Net have been accepted as international standards, first by the ECMA organisation and latterly by the International Standards Organisation in April, 2003, as ISO/IEC 23270 (C#), ISO/IEC 23271 (CLI) and ISO/IEC 23272 (CLI technical report).

.Net also adds various non-standardised extensions to cope with Web services, forms, hooks into operating system functions and so on with the .Net Framework class library. This library includes some 6500 classes, most part of three main components: ASP.Net to help build Web applications and Web services; Windows Forms for client user interface design; and ADO.Net to help connect applications to databases. There’s also a .Net Compact Framework for people working on Pocket PC and allied devices -- this has a subset of the CLR, somewhat reducing the portability of applications.

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