O
offline Networked computers that are not actively connected so that transmission of data is not possible.
offline reader A program to display e-mail messages that have been downloaded to a computer.
ohm A unit of electrical resistance.
online The state in which two or more computers are connected to each other, making possible data transmission.
operating system The program that controls a PC and makes it possible for users to run their own applications. The operating system provides the built-in routines that allow the computer to recognize commands, manage files, connect devices, and perform input/output operations.