Atari's first member of the ST line, the 520ST, relied on both an external power supply and a floppy drive. The 1040STf, shown here, integrated those two components into one case and upped the RAM to 1MB, launching for $999 in 1986 as a complete system with a base unit, a monochrome monitor, and a mouse.
The ST series ran a windowing system known as GEM (Graphical Environment Manager), developed by Digital Research. That, in turn, ran on top of an operating system called TOS (Total Operating System). But, as with a Mac, the user saw only a friendly graphical desktop--no command line here.