DOS extender


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DOS extender

Software that enabled a DOS application to run in extended memory, which is beyond 1MB (that's right... "one megabyte"). Windows 3.0 included a DOS extender. It may seem ridiculous today, but by breaking the 1MB limit, Windows 3.0 solved a very thorny issue and became very popular.

To gain access to extended memory, the extender ran the application in Protected Mode. When the application requested DOS services, the DOS extender handled them. For functions such as a disk access, it reset the machine to Real Mode so DOS could handle them and then switched back to Protected Mode. See VCPI, DPMI and Protected Mode.
References in periodicals archive ?
Microsoft has promised that the next version of Windows will contain a proprietary DOS extender.
Thomson has accomplished its lower pricing by replacing hard-copy documentation with on-line documentation and by removing certain royalty-bearing features of the high-end product, such as database bindings and a third-party DOS extender.
Adding to DESQview's ability to multitask DOS and Microsoft Windows programs, DESQview/X incorporates X Window System graphics and network protocols, plus Rational Systems' 16- and 32-bit shared DOS extender technology to achieve workstation capabilities and performance.