Welcome to BetaWiki!

An open encyclopedia of software history

Did you know...

...that Windows 95 build 58s includes a hidden tabbed mode in the Cabinet?
...that the WarpCenter shell included in OS/2 Warp 4 build 9.012 refers itself to as Lotus SmartCenter?
...that in 1985, Microsoft produced a multitasking MS-DOS that natively supported preemptive multitasking and would later become the base for OS/2?
...that the United States government once filed an antitrust lawsuit against Microsoft over its decision to bundle the Internet Explorer web browser with the Windows operating system?
...that the IA-64 compile of Windows Server 2003 build 2462 includes login banners for a Personal edition of Windows 2000?
...that early builds of Windows Me replaced the safe to shutdown screen with a blue screen due to the removal of real-mode MS-DOS?

Featured article

Multitasking MS-DOS 4

Multitasking MS-DOS 4 refers to an intermediate operating system between MS-DOS and OS/2, which was only offered by certain original equipment manufacturers located in Europe. Unlike its predecessors and even contemporary versions of Microsoft Windows, it implements proper preemptive multitasking with a time-sliced scheduler.

The project was intended to be the successor to MS-DOS 2 and later MS-DOS 3, although it does not share much amount of code with it. The system natively supports the New Executable format from Windows 1.0 in addition to older COM and MZ executables. However, only NE format executables can be multitasked, while running legacy MS-DOS applications will suspend all background tasks. A large part of the operating system was also rewritten in C, including the entirety of the command interpreter (COMMAND.COM), several utilities (such as FDISK.EXE, the disk partition tool) and parts of the DOS kernel (IBMDOS.COM).

Documents suggest that many features such as threading were also planned but removed or otherwise scrapped during development; a successor, version 5.0, was also planned, which would have included support for threaded applications as well as support for protected mode and installable file systems. The DOS 5.0 project eventually morphed into OS/2 1.0, with early test builds shipping under the "DOS 5.0" moniker before the introduction of the OS/2 brand.