The version of Windows that "put Windows on the map." Introduced in 1990, Windows 3.0 replaced the clunky MS-DOS Executive in Windows 2.0 and Windows/386 with a colorful and functional user interface comprising Program Manager and File Manager. Within a couple years, Windows became the major desktop OS worldwide. It Still Booted Into DOS Although the PC still booted up in DOS, Windows 3.0 included a DOS extender that broke DOS's infamous one megabyte memory barrier and allowed programs to use up to 16MB of RAM, a huge amount for that time. Windows 3.0 ran 16-bit Windows applications and DOS applications, and much of its popularity in the beginning was due to multitasking DOS programs. Requiring at least a 16-bit 286 CPU, Windows 3.0 would not run in the first 8086/8088 PCs (see 286). See Windows 3.1 and Windows 3.x modes.