A blank indicates that the file is processed without the use of keys, that the record-address file contains relative-record numbers (a T in position 35), or that the keys in a record-address-limits file are in the same format as the keys in the file being processed.
A file processed without keys can be processed consecutively or randomly by relative-record number.
Input processing by relative-record number is determined by a blank in position 34 and by the use of the CHAIN, SETLL, or SETGT operation code. Output processing by relative-record number is determined by a blank in position 34 and by the use of the RECNO keyword on the file description specifications.