Hard drive platter

A platter from an IBM 1311 hard drive system developed in 1962. The system used six platters with 36 cm diameter, spinning at 1500 RPM. The total capacity was 1,5 MB. The platters were removable. The driving motor alone consumed several kW of power. Copies of this system with higher capacity were newly installed in the Eastern Bloc until the end of the 1980s. Some versions of these drives used hydraulic head positioning.