Attributes and locations of the tapes are noted in the MAREN catalog. They can be used as selection criteria for reservation.
Explicit reservation of a free tape
The free tapes registered in the MAREN catalog can be explicitly reserved for a user (more precisely: for a user ID) with the RESERVE-FREE-VOLUME statement. The user thus becomes the owner of the tape.
When a tape is reserved, attributes can be defined for the tape, e.g. expiration date or comments. Otherwise the values preset by the MAREN administrator are used. The attributes are reflected in the catalog entry fields for the tape in the MAREN catalog. They can be displayed and modified by the tape’s owner.
The following statement reserves a tape with the default device type set by the MAREN administrator and defines an expiration date for it://reserve-free-volume protection=*par(free-date=<date>),remark='my tape'
Implicit reservation of a free tape
Tapes can be implicitly reserved when the automatic free tape allocation of MAREN is enabled, i.e. when the administrator program MARENUCP is running. When a system component detects the reservation request for a tape, it calls MAREN, which then processes the request. The reserved archive number is then returned to the caller.
MAREN then reserves the tapes according to the attributes specified in the reservation request. Tape selection for a reservation can also be influenced by the MAREN administrator via a reservation file or MAREN exits.
No privilege is required for a user to reserve tapes for his/her own user ID. Reserving tapes for other user IDs can be performed by the MAREN administrator. Reserved tapes can be written or read using BS2000 means without calling MAREN explicitly.
The BS2000 user can also use this process with individual software products (e.g. HSMS/ARCHIVE). If the ARCHIVE statement SAVE or EXPORT includes the TAPES=OPERATOR parameter or the TAPES=POOL parameter and the specified directory has no free tape, MAREN implicitly reserves a tape of the specified device type in both cases.
After the command below, the task requests a free tape when OPEN processing of the specified file takes place:
/create-file file-name=work.1,support=*tape(device-type=tape-u4)