32-bit
In computer architecture, 32-bit computing refers to computer systems with a processor, memory, and other major system components that operate on data in 32- bit units. Compared to smaller bit widths, 32-bit computers can perform large calcula ...
DOS extender
A DOS extender is a computer software program running under DOS that enables software to run in a protected mode environment even though the host operating system is only capable of operating in real mode.
DOS extenders were initially developed ...
developed by
Rational Systems
Tenberry Software (previously Rational Systems) was a software company notable for the development of DOS/16M and DOS/4G, which were the first industry standard DOS extender
A DOS extender is a computer software program running under DOS that e ...
DOS
DOS is shorthand for the MS-DOS and IBM PC DOS family of operating systems.
DOS may also refer to:
Computing
* Data over signalling (DoS), multiplexing data onto a signalling channel
* Denial-of-service attack (DoS), an attack on a communicat ...
conventional memory
In DOS memory management, conventional memory, also called base memory, is the first 640 kilobytes of the memory on IBM PC or compatible systems. It is the read-write memory directly addressable by the processor for use by the operating system ...
extended memory
In DOS memory management, extended memory refers to memory above the first megabyte (220 bytes) of address space in an IBM PC or compatible with an 80286 or later processor. The term is mainly used under the DOS and Windows operating systems ...
on
Intel 80386
The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistorslinking time and executes before main application code, so usually DOS/4G initialization messages show up at launch. It can in principle operate within
MS-DOS
MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few oper ...
,
PC DOS
PC or pc may refer to:
Arts and entertainment
* Player character or playable character, a fictional character controlled by a human player, usually in role-playing games or computer games
* ''Port Charles'', an American daytime TV soap opera
* ...
,
DR-DOS
DR-DOS (written as DR DOS, without a hyphen, in versions up to and including 6.0) is a disk operating system for IBM PC compatibles. Upon its introduction in 1988, it was the first DOS attempting to be compatible with IBM PC DOS and MS-DO ...
and other DOS clones, the DOS boxes of
OS/2
OS/2 (Operating System/2) is a series of computer operating systems, initially created by Microsoft and IBM under the leadership of IBM software designer Ed Iacobucci. As a result of a feud between the two companies over how to position OS/2 ...
Windows NT
Windows NT is a proprietary graphical operating system produced by Microsoft, the first version of which was released on July 27, 1993. It is a processor-independent, multiprocessing and multi-user operating system.
The first version of Wi ...
and
Windows 95
Windows 95 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of operating systems. The first operating system in the 9x family, it is the successor to Windows 3.1x, and was released to manufactu ...
, and DOS emulators such as
DOSBox
DOSBox is a free and open-source emulator which runs software for MS-DOS compatible disk operating systems—primarily video games. It was first released in 2002, when DOS technology was becoming obsolete. Its adoption for running DOS games i ...
. However, in practice few DOS/4G games or other applications will run on non-DOS-based versions of
Windows
Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ...
, including
Windows NT
Windows NT is a proprietary graphical operating system produced by Microsoft, the first version of which was released on July 27, 1993. It is a processor-independent, multiprocessing and multi-user operating system.
The first version of Wi ...
,
Windows 2000
Windows 2000 is a major release of the Windows NT operating system developed by Microsoft and oriented towards businesses. It was the direct successor to Windows NT 4.0, and was released to manufacturing on December 15, 1999, and was official ...
and
Windows XP
Windows XP is a major release of Microsoft's Windows NT operating system. It was release to manufacturing, released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct upgrade to its predecessors, Wind ...
, since none of these allow direct access to the hardware as was used for display rendering in those days.
History
DOS/4GW 1.95 was a free limited edition of DOS/4G and was included with the Watcom C compiler with a commercial re-distribution license. It was made widely popular by computer games like '' Doom''.
Initial versions of DOS/4G had trouble with secondary
DMA channel
Direct memory access (DMA) is a feature of computer systems and allows certain hardware subsystems to access main system memory independently of the central processing unit (CPU).
Without DMA, when the CPU is using programmed input/output, it is ...
s on the
ISA bus
Industry Standard Architecture (ISA) is the 16-bit internal bus of IBM PC/AT and similar computers based on the Intel 80286 and its immediate successors during the 1980s. The bus was (largely) backward compatible with the 8-bit bus of the ...
, which prevented 16-bit devices like Gravis Ultrasound series from normally functioning; Gravis even had to develop PREPGAME, a patch utility which updated the game executable with a new version 1.97 to fix the incompatibility.
In case of problems, DOS/4G or DOS/4GW can be replaced with the newer and free DOS/32; a patch utility can even replace DOS/4G code embedded inside a compiled executable file.TOOLS:DOS32A - DOSBoxWiki /ref>
DOS Protected Mode Interface
In computing, the DOS Protected Mode Interface (DPMI) is a specification introduced in 1989 which allows a DOS program to run in protected mode, giving access to many features of the new PC processors of the time not available in real mode. It ...
(DPMI)
*
DOS API
The DOS API is an API which originated with 86-DOS and is used in MS-DOS/ PC DOS and other DOS-compatible operating systems. Most calls to the DOS API are invoked using software interrupt 21h ( INT 21h). By calling INT 21h with a subfunction ...