Sequential Files

Sequential files can be read from the following device types:
  • TAPEFILE
  • DISKETTE
  • DISK
  • DATABASE

Sequential files can only be read in sequential access mode.

The record that is made available by the READ statement is determined as follows:
  • If the file position indicator was set by the processing of an OPEN statement, the record pointed to is made available.
  • If the file position indicator was set by the processing of a previous READ statement, the pointer is updated to point to the next existing record in the file. That record is then made available.

If SELECT OPTIONAL is specified in the file-control entry for this file and the file is not available when this program runs, processing of the first READ statement causes an AT END condition. Since the file is not available, the standard system end-of-file processing is not done when the file is closed.