The common language runtime is the execution engine for .NET Framework applications.

It provides a number of services, including the following:

• Code management loading and execution
• Application memory isolation
• Verification of type safety
• Conversion of IL to native code
• Access to metadata
• Managing memory for managed objects
• Enforcement of code access security
• Exception handling, including cross-language exceptions
• Interoperation between managed code, COM objects, and pre-existing DLLs like unmanaged code and data
• Automation of object layout
• Support for developer services like profiling, debugging
  

Display metadata of one of your .NET programs or libraries by the use of the ILDASM tool:

C# prompt > ildasm app1.exe



We can see the assembly's metadata with all the methods and types in a tree representation. If we click on ' M A N I F E S T ' we get a window, which shows the manifest information. Even if there are a lot of non well readable lines, we are able to identify version information and all the referenced assemblies used to run the displayed executable or library.

Why does the tool we have used right now call ' Intermediate Language Disassembler ' ? Just bring back into our minds that if we compile sources, for instance with the CSharp Compiler (CSC) or any other .NET language compiler, we won't get machine code executable on a computer. Instead we get Microsoft Intermediate Language (MSIL) or shortened to Intermediate Language (IL) stored as an EXE file. To get machine code and to run the EXE we need the Common Language Runtime (CLR) part of the .NET installation somewhere on our computer.