A computer-implemented method for duplexing data from multiple files systems onto a shared tape is disclosed. The computer-implemented method includes receiving a unique identifier of a first tape image written to a primary storage device of a first client system. The computer-implemented method further includes determining that a position of a first end-of-data marker on the first tape image differs from a position of a second end-of-data marker on a tape corresponding to the unique identifier of the first tape image. Responsive to determining that the position of the first end-of-data marker on the first tape image differs from the position of the second end-of-data marker on the tape corresponding to the unique identifier of the first tape image, the computer-implemented method further includes copying a difference in data between the second end-of-data marker on the tape and be first end-of-data marker on the first tape image to the tape.

An apparatus for reading out information from an information carrier includes a reading unit for reading out user information and access information from the information carrier. The user information are stored in a first region of the information carrier and the access information are stored in a second region of the information carrier. The apparatus further includes an access controller for providing access to the user information in dependence on the access information. The access information are stored in a first portion of the second region, and the dummy information are stored in a second portion of the second region according to a similar format as used for storing the access information.

Mounting a data storage medium having information recorded thereon, where: the information is formatted according to a data storage format standard that includes first write and read functions, the information includes first and second datasets, the first dataset includes a first file mark, an index, and an empty space between the second dataset and a combination of the first file mark and the index; receiving, from a first application, a data block and a write command for writing the data block onto the data storage medium; and in response to receiving the write command: determining that the empty space is present in the first dataset, writing, by a second write function, the data block into the empty space, and writing a second file mark in the second dataset; wherein the empty space of the data storage medium is inaccessible to the first write function of the data storage format standard.

Mounting a data storage medium having information recorded thereon, where: the information is formatted according to a data storage format standard that includes first write and read functions, the information includes first and second datasets, the first dataset includes a first file mark, an index, and an empty space between the second dataset and a combination of the first file mark and the index; receiving, from a first application, a data block and a write command for writing the data block onto the data storage medium; and in response to receiving the write command: determining that the empty space is present in the first dataset, writing, by a second write function, the data block into the empty space, and writing a second file mark in the second dataset; wherein the empty space of the data storage medium is inaccessible to the first write function of the data storage format standard.

Mounting a data storage medium having information recorded thereon, where: the information is formatted according to a self-describing format standard that includes first write and first read functions, the information includes first and second datasets, the first dataset includes a first file mark, an index, and an empty space between the second dataset and a combination of the first file mark and the index; receiving, from a first application, a data block and a corresponding write command for writing the data block onto the data storage medium; and in response to receiving the write command: determining that the empty space is present in the first dataset, writing, by a second write function, the data block into the empty space, and writing a second file mark in the second dataset; wherein the empty space of the data storage medium is inaccessible to the first write function of the self-describing format standard.