Power saving system for a disk sensor in rotating disk data storage apparatus

摘要

A flexible magnetic disk drive incorporates a system for reducing the power consumption of a disk sensor according to a power save signal which is supplied from a host system and which indicates whether the disk drive is active or inactive. The disk sensor has a switch connected in series with a resistor, the sensor switch being opened or closed depending upon whether a flexible magnetic disk cartridge is loaded in or unloaded from the disk drive. For powering the disk sensor at least when the disk drive is active, and for unpowering the same when the disk cartridge is unloaded while the disk drive is inactive, an OR gate is provided which has its output grounded via the sensor switch and the resistor, one of its two inputs connected to the power save signal line, and the other input to a circuit point between sensor switch and resistor. Thus the OR gate goes low upon unloading of the disk cartridge while the disk drive is inactive, so that there is no current flow through the resistor even though the sensor switch is then closed. Additional embodiments are disclosed.