Basics of .Net (What is IL,CLR,CTS,CLS ?)

1: IL(Intermediate Language) :-(IL)Intermediate Language is also known as MSIL (Microsoft Intermediate Language) or CIL (Common Intermediate Language). All .NET source code is compiled to IL. This IL is then converted to machine code at the point where the software is installed, or at run-time by a Just-In-Time (JIT) compiler. Microsoft Intermediate Language (MSIL) is a language used as the output of a number of compilers (C#, VB, .NET, and so forth). The ILDasm (Intermediate Language Disassembler) program that ships with the .NET Framework SDK (FrameworkSDK\Bin\ildasm.exe) allows the user to see MSIL code in human-readable format. By using this utility, we can open any .NET executable file (EXE or DLL) and see MSIL code.

MSIL commands are as follows:

ldstr string :—loads the string constant onto the stack.
call function(parameters) :—calls the static function. Parameters for the function should be loaded onto the stack before this call.
pop :—pops a value from the stack. Used when we don't need to store a value in the variable.
ret :—returns from a function.
I will discuss about MSIL in my next article.

2 :- CLR(Comman Language Runtime) Full form of CLR is Common Language Runtime and it forms the heart of the .NET framework.It is the implementation of CLI .The core runtime engine in the microsoft .net framework for executing assemblies. All Languages have runtime and its the responsibility of the runtime to take care of the code execution of the program. For example VC++ has MSCRT40.DLL,VB6 has MSVBVM60.DLL, Java has Java Virtual Machine etc. Similarly .NET has CLR. Internet Exlorer is the example of hosting CLR. CLR have following qualities :-

Garbage Collection :- CLR automatically manages memory thus eliminating memory leaks. When objects are not referred GC automatically releases those memories thus providing efficient memory management.

Code Access Security :- CAS grants rights to program depending on the security configuration of the machine. Example the program has rights to edit or create a new file but the security configuration of machine does not allow the program to delete a file. CAS will take care that the code runs under the environment of machines security configuration.

Code Verification :- This ensures proper code execution and type safety while the code runs. It prevents the source code to perform illegal operation such as accessing invalid memory locations etc.

IL( Intermediate language )-to-native translators and optimizer’s :- CLR uses JIT and compiles the IL code to machine code and then executes. CLR also determines depending on platform what is optimized way of running the IL
code.

3 :- CTS(Comman Type System) :- In order that two language communicate smoothly CLR has CTS (Common Type System).Example
in VB you have “Integer” and in C++ you have “long” in c u have "int" these datatypes are not compatible so the interfacing between them is very complicated. In order to able that two different languages can 1. Basic .NET Framework communicate Microsoft introduced Common Type System. So “Integer” datatype in VB6 and
“int” datatype in C++ will convert it to System.int32 which is datatype of CTS. CLS which is covered in the coming question is subset of CTS.

4 :-CLS(Common Language Specification) :- This is a subset of the CTS which all .NET languages are expected to support. It was always a
dream of Microsoft to unite all different languages in to one umbrella and CLS is one step towards that. Microsoft has defined CLS which are nothing but guidelines that language to follow so that it can communicate with other .NET languages in a seamless manner.

Read More

What are different types of JIT ?

In .net there are three type of JIT.JIT compiler is a part of the runtime execution environment.
Three JIT are following :-

Pre-JIT :- Pre-JIT compiles complete source code into native code in a single compilation cycle. This is done at the time of deployment of the application.

Econo-JIT :- Econo-JIT compiles only those methods that are called at runtime. However, these compiled methods are removed when they are not required.

Normal-JIT :- Normal-JIT compiles only those methods that are called at runtime.
These methods are compiled the first time they are called, and then they are stored in cache. When the same methods are called again, the compiled code from cache is
used for execution.

Read More

What is Manifest in .net ?

An assembly manifest contains all the metadata.It means Assembly metadata is stored in Manifest and it needed to specify the assembly's version requirements and security identity, and all metadata needed to define the scope of the assembly and resolve references to resources and classes.Some points are given please go through it :-
1:- The assembly manifest can be stored in either a Portable Executable file an .exe or dll file with Microsoft intermediate language (MSIL) code or in a standalone Portable Executable file that contains only assembly manifest information.

These four items
1 :- assembly name
2 :- version number
3 :- culture
4 :- strong name information
These four make up the assembly's identity.

Assembly name: A string which specifying the assembly's name.

Version number: A major and minor version number, and a revision and build number. The clr uses these numbers to enforce version policy. Versioning concept is only applicable to global assembly cache (GAC) as private assembly lie in
their individual folders.

Culture: Information on the culture or language the assembly supports. This information should be used only to designate an assembly as a satellite assembly containing culture- or language-specific information.

Satellite Assembly :- An assembly with culture information is automatically assumed to be a satellite assembly.

Strong name information: The public key from the publisher if the assembly has been given a strong name.

List of all files in the assembly: A hash of each file contained in the assembly and a file name. Note that all files that make up the assembly must be in the same directory as the file containing the assembly manifest.

Type reference information: Information used by the runtime to map a type reference to the file that contains its declaration and implementation. This is used for types that are exported from the assembly.

Information on referenced assemblies: A list of other assemblies that are statically referenced by the assembly. Each reference includes the dependent assembly's name, assembly metadata (version, culture, operating system, and so on), and public key, if the assembly is strong named.

Read More