Motor speed observer for data protection in a disc drive

A method for controlling write operations in a disc drive, comprising steps of:

• (a) monitoring speed of a motor;
• (b) predicting speed of the motor at a next angular location of a rotatable recording disc;
• (c) comparing the predicted speed for the next angular location to a selected range of speeds;
• and
• (d) aborting the write operation when the predicted speed is outside the selected range of speeds.

A disc drive comprising:

• a base;
• a disc rotatably attached to the base, the disc including data areas and servo areas written at angular location on the disc;
• and
• a disc drive controller, comprising:
• a motor speed controller;
• a write gate controller;
• and
• a device for predicting the rotational velocity at an upcoming servo area and disabling the write gate controller if the predicted disc rotational velocity is outside a selected range of disc rotational velocities.

A disc drive comprising:

• a hub rotatable to a plurality of angular locations;
• a disc for storing information including data, the disc being attached to the hub, the disc including
• servo areas indicative of an angular location on the disc;
• and
• data areas positioned between the servo area;
• and
• means for predicting disc rotational velocity at an upcoming servo area and disabling a write operation if the predicted disc rotational velocity is outside a selected range of disc rotational velocities.