Applies to: Windows Server 2008, Windows Server 2008 R2

Details

Side-by-side is a concept that was introduced with the Microsoft .NET Framework. It allows the ability to run multiple versions of an application (or component) on the same computer. With side-by-side execution, subsequent installations of other versions of the runtime, an application, or a component will not affect applications that are already installed.

Prior to Microsoft Windows XP and the .NET Framework, DLL conflicts occurred because applications were unable to distinguish between incompatible versions of the same code. An application had no way of knowing if a DLL was compatible with it. As a result, a new version of a component could overwrite an older version and break applications.

Cause

User Action

To solve DLL versioning conflicts, use side-by-side assembly sharing and isolated applications. With side-by-side assembly sharing, multiple versions of the same Windows operating system can run simultaneously. Developers can choose which side-by-side assembly to use. For more information, see

About Isolated Applications and Side-by-Side Assemblies  http://msdn.microsoft.com/en-us/library/aa374029(VS.85).aspx.

To download the CRTs, see Microsoft Visual C++ 2008 SP1 Redistributable Package (IA64) http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=dcc211e6-ab82-41d6-8dec-c79937393fe8. This installs the runtime components of the Visual C++ libraries that are required to run 64-bit applications developed with Visual C++ SP1 on a computer that does not have Visual C++ 2008 SP1 installed.

This package installs the runtime components of the C Runtime (CRT), Standard C++, ATL, MFC, OpenMP, and MSDIA libraries. Libraries that support a side-by-side deployment model (CRT, SCL, ATL, MFC, and OpenMP) are installed in the native assembly cache (also called WinSxS) folder on versions of the Windows operating systems that support side-by-side assemblies.

Additional Resources

• KB976229:  http://support.microsoft.com/kb/976229 
• Guidelines for Creating Side-by-side Assemblies:  http://msdn.microsoft.com/en-us/library/aa375155(v=VS.85).aspx