An indexed file is a program-described DISK file whose access path is built on key values. You must create the access path for an indexed file by using data description specifications.
An indexed file is identified by an I in position 35 of the file description specifications.
The key fields identify the records in an indexed file. You specify the length of the key field in positions 29 through 33, the format of the key field in position 34, and the starting location of the key field in the KEYLOC keyword of the file description specifications.
An indexed file can be processed sequentially by key, sequentially within limits, or randomly by key.