A file is a collection of data that is, typically, stored on disk. As a logical entity, a file enables you to divide your data into meaningful groups. For example, you can use one file to hold all of a company's product information and another file to hold all personnel information. As a physical entity, a file should be considered in terms of its file organization, which refers to the way in which data is stored physically in a file. This determines the way that you access the data subsequently.

This COBOL system supports three file organizations: sequential, relative and indexed. Depending upon the file organization, you have up to three ways of accessing the data:

File Organization Sequential Access Random Access Dynamic Access
Sequential Yes No No
Relative Yes Yes Yes
Indexed Yes Yes Yes