A module definition DEF file (*. def) is a text file containing one or more module statements describing various attributes of a DLL. The DEF file is especially useful when one needs to disable the name mangling of the exported functions and variables.

Communicating with the device drivers from the user-mode apps in Windows can be done by either sending standard I/O requests: Read, Write, or by sending dedicated I/O control codes (IOCTLs). 

Sending standard I/O requests are required when writing standard filesystem drivers. Custom I/O Control Codes can be used when communicating with non-standard (custom) drivers. 

SQL Server supports two authentication modes, Windows authentication mode and mixed mode.

Windows authentication is the default, and is often referred to as integrated security because this SQL Server security model is tightly integrated with Windows. Specific Windows user and group accounts are trusted to log in to SQL Server. Windows users who have already been authenticated do not have to present additional credentials. With Windows authentication, users are already logged onto Windows and do not have to log on separately to SQL Server.

A typical connection string for Windows Authentication would look like:

"Server=localhost;Database=myDataBase;Integrated Security=true;"