PC-DOS 4.01
Press Keyboard right side: Alt+Enter keys to switch to full screen game play, and Alt+Enter keys to return.
How to play PC-DOS 4.01
Each game uses different controls, most DOS games use the keyboard arrows. Some will use the mouse.
PC-DOS 4.01 Description
IBM PC DOS (full name: IBM Personal Computer Disk Operating System) was an operating system for the IBM Personal Computer, manufactured and sold by IBM from the 1980s to the 2000s. Before version 6.1, PC DOS was an IBM-branded version of MS-DOS. For versions 6.1 and later, development diverged and PC DOS became an independent product.
PC DOS 4.0 (internally known as DOS 3.4 originally), shipped July 1988. DOS 4.0 had some compatibility issues with low-level disk utilities due to some internal data structure changes. DOS 4.0 used more memory than DOS 3.30 and it also had a few glitches. Newly added EMS drivers were only compatible with IBM's EMS boards and not the more common Intel and AST ones. DOS 4.0 is also notable for including the first version of the DOS Shell, a full screen utility designed to make the command-line OS more user friendly. Microsoft took back control of development and released a bug-fixed DOS 4.01