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DOS4GW
DOS/4G is a 32-bit DOS extender developed by Rational Systems (later Tenberry Software). It allows DOS programs to eliminate the 640 KB conventional memory limit by addressing up to 64 MB of extended memory on Intel 80386 and above machines. Features Functioning as a highly flexible and reusable memory extension library, DOS/4G allowed programmers to access extended memory without writing specialized code. It embeds itself in the executable file at linking 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, PC DOS, DR-DOS and other DOS clones, the DOS boxes of OS/2, Microsoft Windows, Windows NT and Windows 95, and DOS emulators such as DOSBox. However, in practice few DOS/4G games or other applications will run on non-DOS-based versions of Windows, including Windows NT, Windows 2000 and Windows XP, since none of these allow direct access to the hardware as was used for dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 in the 1980s following the introduction of the Intel 80286 processor (and later expanded upon with the Intel 80386), to cope with the memory limitations of DOS. DOS extender operation A DOS extender is a program that "extends" DOS so that programs running in protected mode can transparently interface with the underlying DOS API. This was necessary because many of the functions provided by DOS require 16-bit segment and offset addresses pointing to memory locations within the first 640 kilobytes of memory. Protected mode, however, uses an incompatible addressing method where the segment registers (now called selectors) are used to point to an entry in the Global Descriptor Table which describes the characteristics of the segment. The two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tenberry Software
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 extenders. See also * Phar Lap Phar Lap (4 October 1926 – 5 April 1932) was a champion New Zealand–bred Thoroughbred racehorse who is widely regarded as New Zealand's greatest racehorse ever. Achieving incredible success during his distinguished career, his initial u ... - competitor References External links Tenberry Software Software companies of the United States Companies based in Phoenix, Arizona {{US-software-company-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Windows NT was Windows NT 3.1 and was produced for workstations and server computers. It was a commercially focused operating system intended to complement consumer versions of Windows that were based on MS-DOS (including Windows 1.0 through Windows 3.1x). Gradually, the Windows NT family was expanded into Microsoft's general-purpose operating system product line for all personal computers, deprecating the Windows 9x family. "NT" was formerly expanded to "New Technology" but no longer carries any specific meaning. Starting with Windows 2000, "NT" was removed from the product name and is only included in the product version string along with several low-level places within the system. In fact, NT was a trademark of Northern Telecom (la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 number in the AH processor register and other parameters in other registers, various DOS services can be invoked. These include handling keyboard input, video output, disk file access, program execution, memory allocation, and various other activities. In the late 1980s, DOS extenders along with the DOS Protected Mode Interface (DPMI) allow the programs to run in either 16-bit or 32-bit protected mode and still have access to the DOS API. History of the DOS API The original DOS API in 86-DOS and MS-DOS 1.0 was designed to be functionally compatible with CP/M. Files were accessed using file control blocks (FCBs). The DOS API was greatly extended in MS-DOS 2.0 with several Unix concepts, including file access using file handles, hierarch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 was initially developed by Microsoft for Windows 3.0, although Microsoft later turned control of the specification over to an industry committee with open membership. Almost all modern DOS extenders are based on DPMI and allow DOS programs to address all memory available in the PC and to run in protected mode (mostly in ring 3, least privileged). Overview DPMI stands for DOS Protected Mode Interface. It is an API that allows a program to run in protected mode on 80286 series and later processors, and do the calls to real mode without having to set up these CPU modes manually. DPMI also provides the functions for managing various resources, notably memory. This allows the DPMI-enabled programs to work in multi-tasking OSes, allowing an O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DOS/32
DOS/32 is an advanced 32-bit DOS extender created for replacing DOS/4GW extender and compatibles. This extender can be used in various environments, from embedded systems to DOS emulators, by both developers and end users alike. Unlike DOS/4GW, DOS/32 is free, open-source and can be extended to create a unique executable file that incorporates the extender memory tool and main application code. Compatibility DOS/32 is compatible with MS-DOS 5.00 through 7.10, Windows 3.x, 95, 98 and Me, NT 3.51 and 4.0 (Service Pack 3 or later), 2000, XP and IBM OS/2 as well as OpenDOS and DOSEMU. DOS/32 has been tested and proved to be fully compatible with software which use DOS/4G, DOS/4GW, DOS/4GW Professional, PMODE/W and CauseWay DOS Extenders. Features The DOS Extender includes a built-in Advanced DOS Protected Mode Interface server supporting v0.9 of the DPMI specification and comes with a set of tools needed to create 32-bit protected mode applications. Like DOS/4G, it requir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 8088-based IBM PC, including the IBM PC/XT as well as IBM PC compatibles. Originally referred to as the PC bus (8-bit) or AT bus (16-bit), it was also termed ''I/O Channel'' by IBM. The ISA term was coined as a retronym by competing PC-clone manufacturers in the late 1980s or early 1990s as a reaction to IBM attempts to replace the AT-bus with its new and incompatible Micro Channel architecture. The 16-bit ISA bus was also used with 32-bit processors for several years. An attempt to extend it to 32 bits, called Extended Industry Standard Architecture (EISA), was not very successful, however. Later buses such as VESA Local Bus and PCI were used instead, often along with ISA slots on the same mainboard. Derivatives of the AT bus stru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 typically fully occupied for the entire duration of the read or write operation, and is thus unavailable to perform other work. With DMA, the CPU first initiates the transfer, then it does other operations while the transfer is in progress, and it finally receives an interrupt from the DMA controller (DMAC) when the operation is done. This feature is useful at any time that the CPU cannot keep up with the rate of data transfer, or when the CPU needs to perform work while waiting for a relatively slow I/O data transfer. Many hardware systems use DMA, including disk drive controllers, graphics cards, network cards and sound cards. DMA is also used for intra-chip data transfer in multi-core processors. Computers that have DMA channels can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doom (1993 Video Game)
''Doom'' (stylized as ''DOOM'') is a 1993 first-person shooter (FPS) game developed by id Software for MS-DOS. Players assume the role of a space marine, popularly known as Doomguy, fighting their way through hordes of invading demons from hell. Id began developing ''Doom'' after the release of their previous FPS, ''Wolfenstein 3D'' (1992)''.'' It emerged from a 3D game engine developed by John Carmack, who wanted to create a science fiction game inspired by ''Dungeons & Dragons'' and the films ''Evil Dead II'' and ''Aliens (film), Aliens.'' The first episode, comprising nine levels, was distributed freely as shareware; the full game, with two further episodes, was sold via mail order. An updated version with an additional episode and more difficult levels, ''The Ultimate Doom'', was released in 1995 and sold at retail. ''Doom'' is one of the most significant games in History of video games, video game history, frequently cited as one of the List of video games considered the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watcom C Compiler
Watcom C/C++ (currently Open Watcom C/C++) is an integrated development environment (IDE) product from Watcom International Corporation for the C, C++, and Fortran programming languages. Watcom C/C++ was a commercial product until it was discontinued, then released under the Sybase Open Watcom Public License as Open Watcom C/C++. It features tools for developing and debugging code for DOS, OS/2, Windows, Linux operating systems, which are based upon x86, IA-32, x86-64 compatible processors. History Though no longer sold commercially by Sybase, the Watcom C/C++ compiler and the Watcom Fortran compiler have been made available free of charge as the ''Open Watcom'' package. Stable version 1.9 was released in June 2010. A forked version 2.0 beta was released that supports 64-bit hosts (Windows and Linux), built-in text editor, 2-phase build system, and the DOS version supports long filenames (LFN). Release history The ''Open Watcom Wiki'' has a comprehensive history. Li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, Windows 2000 for high-end and business users and Windows Me for home users, available for any devices running Windows NT 4.0, Windows 98, Windows 2000 and Windows Me that meet the new Windows XP system requirements. Development of Windows XP began in the late 1990s under the codename "Windows Neptune, Neptune", built on the Architecture of Windows NT#Kernel, Windows NT kernel explicitly intended for mainstream consumer use. An updated version of Windows 2000 was also initially planned for the business market. However, in January 2000, both projects were scrapped in favor of a single OS codenamed "Whistler", which would serve as a single platform for both consumer and business markets. As a result, Windows XP is the first consumer edition of W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
