anchor.diff:      open System.Windows
       open System
   
  -    let mutable FileSystem = 
  -        { new IFileSystem with 
  +    type DefaultFileSystem() =
  +        interface IFileSystem with
               member this.ReadAllBytesShim (fileName:string) = 
                   use stream = this.FileStreamReadShim fileName
                   let len = stream.Length
  
positive.code:                 match Application.GetResourceStream(System.Uri(fileName,System.UriKind.Relative)) with 
                  | null -> IsolatedStorageFile.GetUserStoreForApplication().DeleteFile fileName
                  | _resStream -> ()
              
            }
  #else
  
      let mutable FileSystem = 
          { new IFileSystem with 
              member __.AssemblyLoadFrom(fileName:string) = 
      #if FX_ATLEAST_40_COMPILER_LOCATION
                  System.Reflection.Assembly.UnsafeLoadFrom fileName
  
negative.code:                 System.Text.Encoding.GetEncoding(n)
  #endif                
  
      let mutable FileSystem = DefaultFileSystem() :> IFileSystem 