READ statement is a staple of COBOL transaction processing programming. Reads data from external storage into working store. With or without locks or sharing, sequentially, by random access, or by key. Declarative clauses for
AT END may also be specified, but some programmers prefer explicit
FILE STATUS testing.
As each file resource may contain any type of record in any given slot, COBOL is a "read a file", "write a record" language,
READ takes a filename (FD) and it is up to the programmer to place the record in an appropriate structure if heterogeneous data is saved in the file.