Printer sequential files are files which are destined for a printer, either directly or by spooling to a disk file. They consist of a sequence of print records with zero or more vertical positioning characters (such as line-feed) between records. A print record consists of zero or more printable characters and is terminated by a carriage return (x"0D").
With a printer sequential file, the OPEN statement causes a x"0D" to be written to the file to ensure that the printer is located at the first character position before printing the first print record. The WRITE statement causes trailing spaces to be removed from the print record before it is written to the printer with a terminating carriage return (x"0D"). The BEFORE or AFTER clause can be specified in the WRITE statement to cause one or more line-feed characters (x"0A"), a form-feed character (x"0C") or a vertical tab character (x"0B") to be sent to the printer before or after writing the print record.
Printer sequential files should not be opened for INPUT or I/O.
You can define a file as printer sequential by specifying ASSIGN TO LINE ADVANCING FILE or ASSIGN TO PRINTER in the SELECT clause, for example:
select printseq
assign to line advancing file "printseq.dat".