### Linker Output

Executable files
An executable file is one that can be executed directly: you can run the program by typing the name of the file.

Physical Device Drivers
A physical device driver (.SYS) allows the operating system to interact with a system peripheral, such as a monitor or printer.

Virtual Device Drivers
A virtual device driver (.VDD) allows the operating system to handle input and output with multiple DOS or WIN-OS/2 sessions. Each session can then act as if it has complete control of the input or output device, while actually sharing the control with other sessions.

Dynamic Link Libraries
A dynamic link library file is one that executes when it is called by other processes: it cannot be run independently. Dynamic linking is the process of resolving references to external data and code at runtime or loadtime instead of at link time. A dynamic link library is an object module which can be shared by more than one process.

It contains executable code for common functions, just as a static library (.lib) file does. However, when you link with a DLL (using an import library), the code in the DLL is not copied into the executable file. Instead, only the import definitions for DLL functions are copied, resulting in a smaller executable. At run time, the dynamic link library is loaded into memory, along with the executable file.

Produce an Executable File
Produce a Device Driver
Produce a Dynamic Link Library

Summary of Linker Options
Linker Error Messages
Linker File Name Defaults