The processing of standard labels is requested by means of:
the operand LABEL=(STD,n) of the FILE macro
the operand LABEL-TYPE=*STD(DIN-REVISION-NUMBER=n) of the ADD-FILE-LINK command
In the case of SAM files, the EOV processing routine is started implicitly when DMS detects a tape mark or when the block limit specified in the BLIM operand of the FILE/FCB macro or in the BLOCK-LIMIT operand of the ADD-FILE-LINK command is reached. The routine can also be started explicitly by means of the FEOV macro.
Processing steps
Process outstanding inputs and outputs; for SAM files, the last data block that has been written to the tape may be only partially filled.
Write a tape mark.
Write EOV labels (to match the HDR labels).
Write UTL labels (LABEOV routine).
Write a double tape mark.
If requested: write a checkpoint at the end of the tape.
If DESTOC=YES (from the FILE call), DESTROY-OLD-CONTENTS (from the ADD-FILE-LINK command), or DESTROY=YES (in the catalog entry) has been specified, overwrite the remaining data on the tape.
Initiate a tape swap: depending on the contents of the volume list in the TFT/TST, the next tape is requested or the operator is asked to mount a work tape.
Initiate volume header processing for the new tape.
If a non-BS2000 tape file is extended (OPEN INOUT/EXTEND), it should be noted that the existing part of the file may contain standard labels which are not supported by BS2000, such as labels HDR4 through HDR9. BS2000 writes a maximum of three EOV labels (EOV through EOV3) at the end of the new file section and a maximum of three file header labels (HDR1 through HDR3) at the beginning of any following file sections (and, correspondingly, a maximum of three EOF labels at the end of the file).