What's medium trust level?

Could any body simply tell me what Medium Trust level is ?

And what does it mean :

"More and more ASP.NET hosting providers are enforcing a Medium Trust Policy on their servers.Therefore it is important to make your website work (as much as possible) in environments 开发者_StackOverflow社区where medium trust is enforced."

Thanks

To put this simply there are features of the .NET framework that won't work in Medium Trust such as P/Invoke, no access to the Windows Registry and the Windows Event Log. And also you can access files only in the current directory. You can read more about ASP.NET Code Access Security on MSDN. Here's a nice table from the article: