System One

System One, System I or System 1 may refer to:

Computing

 * Acorn System 1, 8-bit microcomputer by Acorn
 * Atari System 1, an arcade game hardware platform by Atari
 * Cromemco System One, a microcomputer from the early 1980s by Cromemco
 * IBM Q System One, a 2019 circuit-based commercial quantum computer by IBM
 * Line Drawing System-1, an early graphical computer
 * Sega System 1, the arcade system board
 * System 1, the initial operating system version for the Apple Macintosh
 * Tulip System-1, 16-bit personal computer by Tulip

Other uses

 * System-1 Aira, a synthesizer produced by Roland
 * System One, a range of bus passes offered by Transport for Greater Manchester
 * System 1, the fast, automatic mode of thinking, as described in Daniel Kahneman's book Thinking, Fast and Slow