International Business Machines Corporation

William P Quinlan

Jeffrey L Lovgren

Lloyd S Heim

Robert Frederick Herald

Gary Lee Dix

Error information is passed across a limited interface from a disk drive to its using system by making use of the read data line during a fault mode operation. Fault mode operation is detected by a pulse width detector in an adapter between the using system and the disk drive. The pulse width detector detects the presence of a fault signal on the read data line and inhibits the passage of the spindle motor on (MTR ON) signal from the using system to the disk drive. The step signal normally used to index the recording head is passed to the disk drive during fault mode operation. A microcomputer at the disk drive detects the absence of the MTR ON signal and the presence of the step signal and outputs a fault data bit. Thereafter, the fault data word is gated onto the read data line at the rate of one bit per step of the step signal so long as the MTR ON signal is absent.

Method and apparatus for error data feedback in a diskette drive

A control system for applying a magnetic head onto a magnetic disk in random places thereon including a free running oscillator and switching means responsive to pulses from said oscillator and a head load command signal derived from the disk during a revolution thereof for initiating the energization of a head engaging solenoid. The system includes a capacitor which is charged at various rates to produce an initial fast rising current in the solenoid for moving the head into close proximity with the disk, a slowly rising subsequent current in the solenoid for engaging the head with the disk gradually, and a final fast rising current in the solenoid for completing the engagement of the head on the disk.

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Rochester, MN, United States of America

William P Quinlan