.Net Assemblies are the fundamental units of deployment and reuse in .Net applications. They consist of executable code (CIL/MSIL), type metadata, and resources. Assemblies provide a logical grouping of types and resources and record versioning and dependency information that allows side-by-side loading. Assemblies can be private and deployed with an application or shared and installed in the global assembly cache for use by all applications on a machine.

1. .Net AssembliesBy: Muhammad Kamran RafiKami_khan0597@yahoo.com

2. Fundamental unit of deployment, version control, reuse, security permission for a .net based application.Logical unit of distributionTake form of .dll or .exe file Building block of .Net based ApplicationCan consist of Single File or Multiple Files called modulesA module may be generated from different languages..Net Assembly

3. Assemblies are self-describing. Version dependencies are recorded inside assembly manifest. Assemblies can be loaded side-by-side. Installation can be as easy as copying the files that belong to an assembly.Assemblies can be private or shared.Features of Assemblies

4. Assembly MetadataType MetadataCIL CodeResourcesAssembly Structure

5. Assembly NameVersion InformationCultureStrong Name InformationList of files that make up an assemblyType Reference InformationReferenced Assembly InformationAssembly Metadata/Manifest

6. Contains information about the types declared and used in assembly.Classes, interfaces, structs, events , indexers that are used.All information about types i.e. methods, attributes, propertied.Type Metadata

7. JIT complier gets everything it needs from compilerUsed in garbage collection Process.Net provides classes to read metadata (Reflection API)Features of Metadata

8. Assembly Contents pictorial view

9. Code emitted by an appropriate .net language compiler e.g. csc (C# Compiler).MSIL is shipped in portable executable (PE) units.Later JIT compiled to Native Code.Full IL code can be compiled to Native Code using NGEN.exeCIL/MSIL Code

10. Non-executable data that is part of application e.g. images, sounds, videos etc.Resources

11. .NET program execution model (revisited)

12. Private Assembly (placed in application’s execution directory)Shared Assembly (placed in GAC)Types of Assembly

13. Particular location on system that contains all global assemblies

14. Located in OS directory

15. In Windows XP located atC:\Windows\assemblyIt is location where .Net installs its FCL

16. Shared by all .Net apps on that machine

17. Multiple versions of an assembly can live side by sideGAC