C# in a Nutshell

ECMA Standardization

One of the most encouraging aspects about the .NET Framework is the degree of openness that Microsoft has shown during its development. From the earliest public previews, core specifications detailing the C# language, the classes in the FCL, and the inner workings of the CLR have been freely available.

However, this openness was taken to a new level in November 2000 when Microsoft, along with co-sponsors Intel and HP, officially submitted the specifications for the C# language, a subset of the FCL, and the runtime environment to ECMA for standardization.

This action began an intense standardization process. Organizations participating in the effort included Microsoft, HP, Intel, IBM, Fujitsu, Sun, Netscape, Plum Hall, OpenWave, and others. The work was performed under the auspices of ECMA technical committee TC39, the same committee that had previously standardized the JavaScript language as ECMAScript.

TC39 chartered two new task groups to perform the actual standardization work: one to focus on the C# language, the other to focus on what became known as the Common Language Infrastructure (CLI).

The CLI consisted of the runtime engine and the subset of the FCL being standardized. Conceptually, Microsoft’s CLR is intended to be a conforming commercial implementation of the runtime engine specified in the CLI, and Microsoft’s FCL is intended to be a conforming commercial implementation of the class library specified in the CLI (although obviously, it is a massive superset of the 294 classes ultimately specified in the CLI).

After more than a year of intense effort, the task groups completed their standardization work and presented the specifications to the ECMA General Assembly. On December 13, 2001, the General Assembly ratified the C# and CLI specifications as international standards, assigning them the ECMA standards numbers of ECMA-334 (C#) and ECMA-335 (the CLI). Copies of the ECMA standards are available at http://www.ecma.ch.

Critics have claimed that the ECMA standardization process was merely a ploy by Microsoft to deflect Java’s cross-platform advantages. However, the qualifications and seniority of the people working on the standardization effort, and their level of involvement during the lengthy standardization cycle, tell a different story. Microsoft, along with its co-sponsors and the other members of the standardization task groups, committed some of its best and brightest minds to this effort, spending a huge amount of time and attention on the standardization process. Given that this effort occurred concurrently with the development and release of the .NET Framework itself, this level of investment by Microsoft and others flies in the face of the conspiracy theories.

Of course, for standards to have an impact, there must be implementations. At the time of this writing (January 2001), no fully conformant reference implementations were shipping. However, there are several efforts already under way to provide open and shared source implementations of the C# language and the CLI, for both commercial and noncommercial use.

Microsoft is working with Corel to provide a shared source implementation of the CLI, as well as C# and ECMAScript compilers that target it. This project, codenamed Rotor, is expected to ship in 2002, and will run on both Windows and FreeBSD platforms. Although specific details of the shared source license were not available at the time of this writing, it is expected that this CLI implementation will be licensed for noncommercial use by researchers, hobbyists, and academics.

However, Microsoft’s implementation is not the only game in town. Other CLI implementations include the Mono project and dotGNU.

The Mono project (http://www.go-mono.com), started by Ximian Corporation, is aiming to provide full open source (GPL and LGPL) implementations of not only the CLI platform and the C# compiler, but also a larger set of classes selected from Microsoft’s .NET Framework FCL. In addition to the internal resources that Ximian has committed to the project, the Mono project has also attracted attention from the broader open source community, and appears to be gathering steam.

Finally, consider the open source (GPL) dotGNU project (http://www.dotgnu.org). While not as high-profile as Mono, dotGNU has also been making headway, and includes some interesting and unique concepts. The core of dotGNU is Portable.NET, which was originally developed by a lone developer (Rhys Weatherley) before merging his project with dotGNU in August 2000. There are unique aspects to the dotGNU project, including the fact that it was originally designed around a CIL interpreter rather than a JIT compiler (although the team plans to add JIT compilation at a later date), and the developers’ plan to support directly executing Java binaries.

Beyond these three, it is very likely that more implementations of the CLI will arise over time. While it is too early to say whether the .NET Framework (in the form of the CLI) will ever be available on as many platforms as Java is, the degree of openness and the level of community interest is very encouraging.