Medium System installations often had tape clusters (four drives integrated into a mid-height cabinet) for magnetic tape input and output. Free-standing tape drives were also available, but they were much more expensive. Tape was a major storage medium on these computers, in early days it was often used for father-son batch updating; with additional disk becoming cheaper as time moved on it became relegated as a library/backup device that contained all the data files and sometimes the program files (using the MFSOLT utility) for a particular application or customer/client.
