What is the Global Assembly Cache (GAC)?

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The Global Assembly Cache is a machine-wide code cache that is stored in a folder in the Windows directory. It stores the .NET assemblies that are specifically designated to be shared by all applications executed on the system.

The Global Assembly Cache (GAC) is a central repository in the Microsoft .NET Framework where shared assemblies are stored. These shared assemblies are .NET assemblies (compiled code libraries) that are intended to be used by multiple applications on the same system. The GAC stores these assemblies in a location that is globally accessible to any .NET application running on the system.

Key points about the Global Assembly Cache (GAC) include:

  1. Centralized Storage: The GAC provides a centralized storage location for shared assemblies, making it easier to manage and access them.
  2. Versioning: It supports versioning of assemblies, allowing multiple versions of the same assembly to coexist on a system. This ensures that applications can use the specific version of an assembly they require without conflicts.
  3. Strong Names: Assemblies stored in the GAC are required to have a strong name, which is a globally unique identifier that includes a cryptographic hash of the assembly’s contents. This helps ensure the integrity and uniqueness of assemblies in the GAC.
  4. Administration: Administrators have control over what assemblies are installed in the GAC, which helps maintain system integrity and security.
  5. Global Accessibility: Assemblies stored in the GAC are accessible to any .NET application running on the system, regardless of where the application is installed.

In an interview, it’s good to mention these points to demonstrate understanding of how the GAC works and its importance in the .NET development ecosystem.