Process boundary
Applications
running on windows are protected by each other. Each application has a process
and they are separated (isolated) by their process boundary. So if an
application crashes due to some issues, its process gets killed, but the other
applications are unaffected.
The process
boundary provides great security benefits. It also adds few restrictions when
processes communicates each other. This is because memory addresses on one
process has no meaning for the other
application. The components within an application communicate (transfer data)
freely but the data transfer between the processes would require additional
work like marshaling (copy data from one
process , pass the data and place it to meaningful address location of
other process)
Application domains
App domains carry
the same concept of providing isolation and security but they are within the
process. By default , .NET CLR create three application domains to any .NET
application with names (System ,Shared and default) .User can programmatically
add new domains to applications. The
cross-domain communication requires marshaling.
Hosting applications
(Ex: IIS processes) utilizes multiple .NET app domains to load web applications
in separate app domain so that applications behave so distinct and isolated
each other.
The brief
description of CLR created domains for an application is listed below.
System domain : The first application
domain created on the application. It is responsible for creating other two
domains ( Shared and default). This domain loads mscorlib dll to shared
application domain.
Shared Domain: This is the place where
the shared code exists . There is a type of assemblies called domain neutral
assemblies(their code can be accessible in all app domains). They are getting
loaded to this app domain.
Default domain: The domain where application specific
data and assemblies resides.
