(1) To manipulate data in the computer. The computer is said to be processing no matter what action it is taking upon the data; whether the data are actually being updated in a database or just being displayed on screen.

In order to evaluate a computer system's performance, the time it takes to process data internally is often analyzed separately from the time it takes to get it in and out of the computer. The I/O (input/output) is usually more time consuming than the processing. For an explanation of how the computer processes data, see "Processing" under the term computer. See also process technology.

(2) The actual running of a program module. If two instances of the same program are launched, two processes are running in the computer. When a computer is booted, numerous processes are started. Some are parts of the operating system, while others are applications that have been designated to run at startup. In a Windows computer, pressing Ctrl-Alt-Del launches the Task Manager, which displays all running processes. See Windows processes.