sentences:  The files should then be uploaded to a central computer server and copies can be burned to optical media, or copied to USB flash drives owned by the researchers, scholars and students working with the material.Recordable compact discs are commonly used over magnetic tape for the preservation of oral histories over a long period of time.Compact Cassette tapes and Videotape were popular but have been almost completely replaced by optical media such as CD-R and DVD media.