24/12 COM component object model –

DATE 24/12/2010 Friday

COM component object model – it is a specification from Microsoft which advises never built software as a monolithic unit in spite it tells building of software by dividing it into smaller library and then build it as software.

The advantage of building software using a COM architecture will be like –

1 maintenance of the software easier.

2 reusability – which allows using a library or component under multiple software .

COM Interoperability - Com component or library were unmanaged so OS dependent . When Microsoft introduce .net it has straight away provided tools to the industry which can convert Com libraries into managed version and then consumed under .net application development.

The managed version of the COM library is known as RCW (runtime callable wrapper ) . in the same thing it also providing option for converting .net libraries into unmanaged version CCW( com callable wrapper ) for consuming the under COM application.

Concerns and criticism related to .NET-

1 Managed applications that executes under the .net framework CLR or JAVA JVM required more system resources when compiled with unmanaged applications but some applications have however shows to performance better in managed version when compiled wit unmanaged version..

2 in a managed environment such as the Microsoft framework CLR or JAVA’s JVM the regularly accruing garbage collection for reclaiming memory suspends execution of the application for an unpredictable waits of time typically not more than few milliseconds.

3 as JIT languages can be more easily reveres engrained them machine code to source code used by an application ,so there is concern over possible loss of trade secrete many obfuscation techniques already developed however can help to prevent this . Indeed Microsoft visual studio 2005 (.net 2.0) includes such a tool.

4 since the framework is not preinstalled on older versions of windows an application is required is must verified that it is present or not.

5 newer versions of the framework 3.0 and up) are not preinstalled on any version of the windows OS and some developers have expressed concerns about the large size.