Related:

• VMS: /V-M-S/ n. DEC's proprietary operating system for its VAX minicompute
  one of the seven or so environments that loom largest in hacker folklore....
• VMS /V-M-S/ n. DEC's proprietary operating system for its VAX minicompute
  one of the seven or so environments that loom largest in hacker folklore....
• IOS: Ignore Operating System
• Never trust an operating system.
• ROS: Reject Operating System
• There's no bug in this program. It's the operating system!!
• TOS: Tape Operating System
• TOS: Trash Operating System