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2 System Function: Indicates a step in the flow of dataExternal: Represents an object that sends information or data to the system, or takes information from the system, but is not itself part of the systemSystem Data Exchange Line: Indicates the direction of the flow of data as it moves from one point in the system to anotherData Store: The location where data rests when it is neither flowing nor being operated on; a data store can be a database, hard disk or a file on a disk
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