In a record file system, a programmer designs the records that may be used in a file. All application programs accessing the file, whether adding, reading, or updating records share an understanding of the design of the records. In DOS/360, OS/360, and their successors there is no restriction on the bit patterns composing the data record, i.e. there is no delimiter character; this is not always true in other software, e.g., certain record types for RCA File Control Processor (FCP) on the 301, 501, 601 and 3301.