Seagate technology (ST)
The ST412/506 bus is a bus system introduced by Seagate in 1980 for hard dis ks with a storage capacity of 5 MB, to which two hard disks could be connected. The transfer rate between drive and controller was 5 Mbit/s with MFM coding and 7.5 Mbit/s with Run Length Limited ( RLL). The controller was located on a separate plug-in card and could control the two hard disks with a maximum of 16 heads and 1024 cylinders.