Jeff Parsons, who unveils the history of the IBM PC celebrating its 40th anniversary in 2021 with an IBM PC emulator running in a browser, is drawing attention with the release of BASIC-DOS, which supports multitasking.
IBM PC was equipped with PC DOS, an operating system developed by Microsoft. Commands, such as DIR, TIME, and TYPE, which have been installed since the early versions of PC DOS, are still available at the Windows command prompt. PC DOS was an operating system that Microsoft only renamed MS-DOS, but it gradually adds unique features of IBM. As the demand for multitasking increased in the late 1980s, the multitasking function was implemented in MS-DOS version 4 released in 1986, but it was not implemented in PC DOS, which emphasizes compatibility.
Since IBM PC occupied a significant share at the time, many third-party software such as DoubleDOS and DESQview were born to realize multitasking in PC DO. At the time of launch, DoubleDos also appealed in advertisements that it could add multitasking capabilities to IBM PCs without adding hardware or changing software.
IBM co-developed OS/2, an operating system that supports multitasking, with Microsoft, but did not maintain compatibility with PC DOS, and eventually stopped updating version 4.52 released in 2002.
Developers are releasing Basic DOS, an operating system that supports multitasking operation, thinking what operating system would have been made if Microsoft and IBM had a strong partnership to develop PC DOS that responds to multitasking. Related information can be found here.