386 DOS-Extender
From Computer History Wiki
The 386|Dos-Extender was the first real MS-DOS extender created by Phar Lap.
By using special compilers Watcom C 386, and HighC 386 you could create a 32bit program that would run on an unmodified MS-DOS system equipped with a 386 processor. It was significantly easier to deploy 386 extended applications, however it did carry a significant price tag, compared to deploying OS/2 2.0, although it was much more simpler.