MS-DOS 4.0 (multitasking)

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MS-DOS 4.0
Multitasking MS-DOS 4.00 COMMAND.COM session running in VirtualBox.
Developer	Microsoft
Written in	x86 assembly
OS family	DOS
Source model	Open source
Initial release	May 15, 1986; 39 years ago (May 15, 1986)
Final release	4.10.30 / May 10, 1988; 37 years ago (May 10, 1988)[1]
Update method	Re-installation
Package manager	None
Platforms	x86
Kernel type	Monolithic
Default user interface	Command-line interface (COMMAND.COM)
License	MIT License[2]
Support status
Unsupported

MS-DOS 4.0^[a] was a multitasking release of MS-DOS developed by Microsoft based on MS-DOS 2.0. Lack of interest from OEMs, particularly IBM (who previously gave Microsoft multitasking code on IBM PC DOS included with TopView), led to it being released only in a scaled-back form. It is sometimes referred to as European MS-DOS 4.0, as it was primarily used there. It should not be confused with PC DOS 4.00 or MS-DOS 4.01 and later, which did not contain the multi-tasking features.

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