dia (usually magnetic tape) to free the hard disk space they occupied. This is now
normally done for long-term storage but in the 1960s, when disk was much more expensive, files were often shuffled regularly
between disk and tape. [Computer and Information Sciences] 
n., A single file containing one or (usually) more separate files plus information to allow them to be extracted (separated) by a
suitable program. [Computer and Information Sciences] 
v., To copy data onto a different disk or tape for backup. 