Putting data on tape is the same as banishing the data. Tape is not designed to provide easy, immediate access to information; it's typically written in a proprietary backup format and can only be searched sequentially. It is designed for the infrequent and unlikely retrieval of backup data when primary storage fails. It is optimized for density not access. Besides the inaccessibility of tape, there is the risk of storing important archives on a medium not intended for permanence. Tape is used for periodically overwriting files, not for preserving valuable fixed content in a permanently etched, unalterable form. Unlike certain types of optical media, tape is not native WORM compliant, and tape is susceptible to environmental influences such as magnetic interference. While tape is adequate for backup data, it is not the ideal choice for high-value fixed content.