North Star Computers was one of the earliest manufacturers of microcomputers. Before they started making their first computer, the North Star Horizon, they made floppy disk drives for S-100 bus computers. They included a disk operating system called North Star DOS (or N*DOS). The Horizon used the North Star disk controller and operating system. It was one of the first microcomputers that had multi-user features.
Their second computer, called the North Star Advantage, ran CP/M, and had the keyboard and monitor built-in. The graphics were very powerful for their time. When the IBM PC came out, North Star made an MS-DOS compatible processor card that could be added to the Advantage.
Their third computer, the North Star Dimension, was multi-user like the Horizon, but MS-DOS based.
Because their products in the early 1980s were only MS-DOS compatible, not fully PC compatible, they never sold very many, and the company went out of business.