.DAT:The extension that is often used to indicate a data file.
data symbol:The address of a global or static data object. The concept of data symbol includes all data objects except local (stack-allocated) or dynamically allocated data.
.DBG:The extension for a file that is created by LINK when the /CO and /TINY options are used. The file contains symbolic debugging information.
debugger:A program that allows the programmer to execute a program one line or instruction at a time. The debugger displays the contents of registers and memory to help locate the source of problems in the program. An example is the Microsoft CodeView debugger.
debugging information:Symbolic information used by a debugger, especially information in the Microsoft Symbolic Debugging Information format that is used by the Microsoft CodeView debugger.
.DEF:The extension for a module-definition file.
default data segment:See “DGROUP.”
default library:A standard library that contains routines and data for a language. The language's compiler embeds the name of the default library in the object file in a COMMENT record. The embedded name tells LINK to search the default library automatically.
DGROUP:The group that contains the segments called _DATA (initialized data), CONST (constant data), _BSS (uninitialized data), and STACK (the program's stack). Also called default (or automatic) data segment.
dialog box:A box that appears when you choose a command that requires additional information.
disassemble:To translate binary machine code into the equivalent assembly-language representation. Also called unassemble.
disassembly:The assembly-language representation of machine code, obtained by disassembling the machine code.
.DLL:The extension for a dynamic-link library.
DLL:A dynamic-link library.
.DOC:The extension that is often used to indicate a document file.
DOS application:A program that runs only under DOS. A DOS executable file contains a header and one contiguous block of segments.
DOS-extended:An application that is able to be run by the DOS Extender in extended or expanded memory.
DOS Extender:A program that lets an application run in extended or expanded memory.
DOS session:Under Windows, a full-screen emulation of the MS-DOS environment started using the DOS Prompt in the Program Manager Main Group. The DOS Prompt program item starts a copy of the MS-DOS command interpreter (COMMAND.COM).
double precision:A real (floating-point) numeric value that occupies eight bytes of memory. Double-precision values are accurate to 15 or 16 digits.
DPMI:A server that provides extended or expanded memory. Examples of DPMI servers include a DOS session under Windows and Microsoft's MSDPMI.EXE.
drag:To move the mouse while holding down one of its buttons.
dump:To display the contents of memory at a specified memory location.
dynamic link:A method of postponing the resolution of external references until load time or run time. A dynamic link allows the called routines to be created, distributed, and maintained independently of their callers.
dynamic-link library:A file, usually with a .DLL extension, that contains the binary code for routines and data that are linked to a program at run time.