Windows was originally a 16-bit graphical layer for MS-DOS that was written by Microsoft. As it grew, it gained the ability to handle 32-bit programs and eventually became totally 32-bit when Windows NT and 2000 came out. After Windows 95, Microsoft began to remove dependencies on DOS and finally fully implemented the separation in Windows 2000. Windows has many advanced features as well as many platform specific problems. It possesses an Application Programming Interface that consists of thousands of mostly undocumented GUI functions as well as having varying degrees of MS-DOS compatibility. Additionally, with the advent of NT (New Technology), Windows relies completely on the NT kernel instead of its MS-DOS subsystem, the NT kernel emulating the necessary DOS functionality. In addition to the NT kernel, Microsoft has also introduced many API wrappers, such as the MFCs (Microsoft Foundation Classes), COM (Component Object Model), and .NET technologies. The most popular languages for use on Windows include Visual Basic/VB6 and C/C++, although C++ is quickly being replaced by the .NET platform, specificially C# (C Sharp).