A volume set (or tape set) consists of the tapes on which a file set is stored. It contains precisely one file set (DIN 66029). A “single-tape file” can thus be regarded as a special “file set on one tape”.
A volume series is the set of tapes formed by the volume list in the catalog entry for a file. It is not necessarily identical with the tape set. The volume series or the volume list may also contain volumes which have not (yet) been used for the file. However, the file must begin on the first tape of the volume series. The tape sequence is the same as the sequence of file sections.
If the file is part of a file set, other files may also be stored on the first tape of the volume series; however, the file must begin on this tape.
The tape owner is the user under whose user ID the first file was written on the tape. When this first file is created, this user ID is written into the appropriate field of the VOL1 label as the “owner identifier”. All tapes of a volume set should have the same owner identifier in their VOL1 labels.
Shareability of tapes and tape files
The “shareability” of a tape depends on whether or not the first file on the tape is shareable. If a tape file is created by means of the FILE macro or CREATE-FILE command, it is implicitly cataloged as shareable (output field USER-ACC(ESS)=ALL-USERS). The tape is then also shareable. Tapes and tape files can be locked against access from other user IDs if the file is
first cataloged using the CATAL macro (which implies USER-ACC=OWNER-ONLY) and the FILE macro is then issued with the operands DEVICE and VOLUME;
cataloged using a FILE macro (operands DEVICE and VOLUME) and then made nonshareable by means of a CATAL macro (operands STATE=UPDATE and SHARE=NO). In this case the CATAL macro must be effective before the file is opened for the first time.
cataloged using the CREATE-FILE command (entries USER-ACCESS=*OWNER-ONLY and SUPPORT=*NONE) before the MODIFY-FILE-ATTRIBUTES command with the VOLUME and DEVICE-TYPE operands is issued.
cataloged using the CREATE-FILE command and then declared non-shareable with the MODIFY-FILE-ATTRIBUTES command via the USER-ACCESS=*OWNER-ONLY operand. The MODIFY-FILE-ATTRIBUTES command must take effect before the file is opened for the first time.