Global Assembly Cache

The Global Assembly Cache or GAC is a machine-wide .NET assemblies cache for Microsoft's CLR platform. The approach of having a specially controlled central repository addresses the shared library concept and helps to avoid pitfalls of other solutions that lead to drawbacks like DLL hell.

Requirements

Assemblies residing in the GAC must adhere to a specific versioning scheme which allows for side-by-side execution of different code versions. Specifically, such assemblies must be strongly named.

Usage

Microsoft provides two ways to interact with the GAC: the Global Assembly Cache Tool (gacutil.exe) and the Assembly Cache Viewer (shfusion.dll).

Global Assembly Cache Tool

gacutil.exe is an older command-line utility that shipped with .NET 1.1 and is still available with the .NET SDK.

One can check the availability of a shared assembly in GAC by using the command:<pre>gacutil.exe /l <assemblyName></pre>

One can register a shared assembly in the GAC by using the command:<pre>gacutil.exe /i <assemblyName></pre>

Or by copying an assembly file into the following location:<pre>%windir%assembly</pre>Note that for .NET 4.0 the GAC location is now:<pre>%windir%Microsoft.NETassembly...</pre>

Other options for this utility will be briefly described if you use the /? flag, i.e.:<pre>gacutil.exe /?</pre>

Assembly Cache Viewer

The newer interface, the Assembly Cache Viewer, is...
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