Linear recording executing optimum writing upon receipt of series of commands including mixed read and write commands

A non-transitory computer program product for writing data to tape, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a computer to cause the computer to perform a method comprising:

• receiving, by the computer, a series of commands, the series of commands including mixed read, overwrite, and append write commands;
• causing, by the computer, reading of data from a specified position of the tape using a head and storing the data in a buffer in response to a read command;
• and
• causing, by the computer, writing data stored in the buffer starting from an appended data end position of the tape in response to an append write command.

An apparatus, comprising:

• a head;
• a controller coupled to the head,
• logic integrated with and/or executable by the controller, the logic being configured to:
• in response to receipt of an append write command, cause storing of data stored in a buffer to a non-volatile memory starting from an appended data end position;
• cause sending a completion notification of the append write command to a higher-level device when data in the buffer is written in the non-volatile memory;
• cause moving to a tape writing position where the data stored in the non-volatile memory is to be written;
• and
• cause performance of append writing on a basis of a predetermined criterion so as to minimize a moving distance by which a tape travels relative to a head, when moving from an end position on the tape of read data for a m-th read command to a reading start position for a subsequent n-th read command, wherein n=m+1.