[Yeo Kheng Meng] didn’t cheat by simply running MS-DOS on a modern PC, either: he tested the client on a real 1984 vintage IBM 5155 Portable PC. This semi-portable PC/XT model sports a 4.77 MHz ...

He still oversees the project to this day. MS-DOS, IBM-DOS, and other DOS derivatives were the most popular operating systems for PCs from the first IBM PC in 1981 to around the mid-1990s.

My first IBM was the original 5150 ... Today you can relive the experience of using all kinds of MS-DOS versions—as well as PC-DOS, DR-DOS, and many retro Windows versions—in your web browser ...

It was a clone of the original IBM PC 5150, initially released in 1981 ... The operating system diskette for this PC just happened to be running MS-DOS 5.0, so that was where I started.

Now, thanks to [Mike Chambers], you can add to the IRC ecosystem by hosting your very own MS-DOS based IRC server ... can get up on the 40-year-old IBM 5150, and should absolutely scream on ...

He offered IBM a non-exclusive contract for the use of MS-DOS, which gave him the right to sell it to other computer companies. IBM, which was not used to subcontracting, was not suspicious enough ...