The HX DOS Extender is a free DOS extender

DOS extender

A DOS extender is a computer software program which enables software to run under a protected mode environment even though the host operating system is only capable of operating in real mode....

 with built-in Win32 PE file format

Portable Executable

The Portable Executable format is a file format for executables, object code and DLLs, used in 32-bit and 64-bit versions of Windows operating systems. The term "portable" refers to the format's versatility in numerous environments of operating system software architecture...

 support. Usually the purpose of a DOS extender is to make protected mode

Protected mode

In computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units...

 features, especially large memory and 32-bit

32-bit

The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....

 addressing, available for DOS

DOS

DOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.Related...

 applications. HX fully supports this goal, but goes some steps further. A Win32 API

Windows API

The Windows API, informally WinAPI, is Microsoft's core set of application programming interfaces available in the Microsoft Windows operating systems. It was formerly called the Win32 API; however, the name "Windows API" more accurately reflects its roots in 16-bit Windows and its support on...

 emulation

Emulator

In computing, an emulator is hardware or software or both that duplicates the functions of a first computer system in a different second computer system, so that the behavior of the second system closely resembles the behavior of the first system...

 layer is part of HX which allows many Win32 console application

Console application

A console application is a computer program designed to be used via a text-only computer interface, such as a text terminal, the command line interface of some operating systems or the text-based interface included with most Graphical User Interface operating systems, such as the Win32 console in...

s to run in DOS. The developers say this emulation goes far beyond similar approaches in other extenders (such as Borland

Borland

Borland Software Corporation is a software company first headquartered in Scotts Valley, California, Cupertino, California and finally Austin, Texas. It is now a Micro Focus subsidiary. It was founded in 1983 by Niels Jensen, Ole Henriksen, Mogens Glad and Philippe Kahn.-The 1980s:...

's PowerPack, WDOSX and Phar Lap

Phar Lap (company)

Phar Lap was a software company specializing in software development tools for DOS operating systems. They were most noted for their software allowing developers to access memory beyond the 640 KiB limit of DOS and were an author of the VCPI standard.Phar Lap Software, Inc. was founded in April...

 TNT).

The Win32 layer has limited support for Windows, DirectDraw

DirectDraw

DirectDraw is part of Microsoft's DirectX API. DirectDraw is used to render graphics in applications where top performance is important. DirectDraw also allows applications to run fullscreen or embedded in a window such as most other MS Windows applications. DirectDraw uses hardware acceleration if...

, GDI

Graphics Device Interface

The Graphics Device Interface is a Microsoft Windows application programming interface and core operating system component responsible for representing graphical objects and transmitting them to output devices such as monitors and printers....

 and OpenGL

OpenGL

OpenGL is a standard specification defining a cross-language, cross-platform API for writing applications that produce 2D and 3D computer graphics. The interface consists of over 250 different function calls which can be used to draw complex three-dimensional scenes from simple primitives. OpenGL...

 graphics. This lets some Windows GUI

Graphical user interface

In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...

 applications run in DOS, including Bochs

Bochs

Bochs is a portable x86 and x86-64 IBM PC compatible emulator and debugger mostly written in C++ and distributed as free software under GNU Lesser General Public License...

, QEMU

QEMU

QEMU is a processor emulator that relies on dynamic binary translation to achieve a reasonable speed while being easy to port on new host CPU architectures....

, MPlayer

MPlayer

MPlayer is a free and open source media player. The program is available for all major operating systems, including Linux and other Unix-like systems, Microsoft Windows and Mac OS X. Versions for OS/2, Syllable, AmigaOS and MorphOS are also available. The Windows version works, with some minor...

, DOSBox

DOSBox

DOSBox is emulator software that emulates an IBM PC compatible computer running MS-DOS. It is intended especially for use with old PC games. DOSBox is free software....

and some (mostly older) games.

HX DOS Extender contains the following components:

• HXRT: the extender runtime
  • HDPMI: a DPMI server for DOS (can be used as standalone tool)
  • DPMILD32: Win32 PE file loader
  • Win32 API emulation library
  • HXLdr32: a TSR Win32 PE loader
  • PEStub: a Win32 PE header stub tool to add a Win32 PE loader to DOS entry point
• HXGUI: GUI extension
• HXDEV: development support
• HXSRC: source code

External links

• HX website
• HX and general DOS development and support forum
• Alternative / additional docs and list of compatible software