Chapter 2. Introduction to the Microsoft .NET Developer Platform

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By Matthew Lyons

IN THIS CHAPTER

• Tight Language Interoperability

• Metadata

• JIT Compilation

• Garbage Collection

• Object-Oriented Programming

• Code Access Security

• Base Class Library

• Native Code Interoperability

Over time, new technologies and new paradigms sweep through the computer industry. From mainframes to minicomputers to PCs to embedded computers, hardware has gotten smaller, faster, and less expensive. This has put an amazing amount of computing power at our fingertips.

While hardware has changed quite dramatically, software has undergone fewer changes, though the changes are still significant. Programming has moved from assembly-level languages to high-level languages. Reinventing the wheel has become less prevalent as components have become more readily available to purchase and use. High-quality debuggers have become an absolute necessity in software development. What Microsoft has done with the .NET Framework may not be as dramatic as these paradigm shifts, but the framework is significant in that it combines many of the benefits of previous programming successes into a single package. This alone can allow for large productivity gains over many current development environments used today.

The .NET Framework brings the following benefits together:

• Tight language interoperability ”All .NET Framework compilers emit MSIL, a Microsoft intermediate language.

• Metadata ”Every .NET executable or library (known as an assembly) contains not only the method bodies and signatures, but also rich information about defined data types, names of class fields, and other related information collectively called metadata.

• A just-in-time (JIT) compilation environment ”Identical compiled files can run on different platforms, and JIT compilers can make platform-specific optimizations.

• Garbage collection ”The .NET Framework automatically deallocates memory, eliminating memory leaks common with C/C++ programming.

• Object-oriented programming ”At its core , the .NET Framework uses object-oriented programming concepts extensively.

• Code access security ”A rather innovative feature in the .NET Framework is the ability to grant and enforce granular permissions based on code identity.

• Base class library ”The .NET Framework provides a secure library of classes that enable critical functionality such as threading, I/O, and networking in addition to higher-level programming services such as XML manipulation, cryptography, and system management.

• Interoperability with native code ”Previous investments in writing COM objects aren't lost. COM objects are treated very much like native .NET Framework objects.

TIP

Because the following terms are used extensively in this chapter and throughout the book, you should become familiar with their definitions now:

Native code ”Programs or libraries that have been compiled to machine language for a specific hardware architecture, such as x86. On Windows computers, native code is generally packaged in DLL and EXE files.

Unmanaged code ”Same as native code.

Managed code ”Programs or libraries that have been compiled to run on the .NET Framework. Like unmanaged code, managed code is frequently packaged in DLL and EXE files.

Assembly ”Logical unit of code separation in the .NET Framework. Usually a single managed DLL or EXE is an entire assembly. However, an assembly can contain multiple files.

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