The IBM 3350 Direct Access Storage Facility, was code-named Madrid,(not sure why) was introduced in 1975 for use with IBM System/370.
It was the dominant product in the industry for its time . It had non-removable disk packs that were sealed. The disk geometry was 555 cylinders, 30 heads, with 19K bytes per track which gave the it a storage capacity of 317,498,850 bytes. Each unit had contained two HDAs and they were installed in “strings” of units. How far we have come.less
The IBM 3850 Mass Storage System (a.k.a The MSS) was debuted in October of 1974.
It was a hybrid type device using the then very popular IBM 3330 disk subsystem. It was used to hold large amounts of infrequently accessed data in mainframe environments by creating images of disk devices. It consisted of a library of cylindrical plastic cartridges, two by four inches each containing a tape spool. These 50 MB cartridges were held in a hexagonal array of bins. In August 1986 it was discontinued. Seems crude by today's standards but , in many ways it was ahead of its time.less
