# US 5,333,084 A · Electronically alignable flexible disk drive

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- Number: US 5,333,084 A
- Document ID: US5333084A
- Status: Granted
- Kind: A
- Application number: 07/611,962
- Filed: 1990-07-13
- Granted: 1994-07-26
- Earliest claimed: 1990-07-13
- Assignees: Gregory M. Galloway
- Inventors: Gregory M. Galloway; Titus E. Davis; Roger O. Williams
- Web page: https://patentgrep.com/patent/US5333084A

## CPC

- G11B 5/02: Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
- G11B 5/035: Equalising
- G11B 5/5534: {Initialisation, calibration, e.g. cylinder "set-up"}
- G11B 5/56: with provision for moving the head {support} for the purpose of adjusting the position of the head relative to the record carrier, e.g. manual adjustment for azimuth correction or track centering ({G11B5/52,} G11B5/54, G11B5/58 take precedence)
- G11B 20/1816: {Testing}
- G11B 27/36: Monitoring, i.e. supervising the progress of recording or reproducing {(for digital recording G11B20/00 and s.gr.; for monitoring, testing or measuring of TV recorders of the type covered by H04N5/76 and subgroups, see H04N17/06)}
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)

## Abstract

A disk drive in which the radial alignment, track zero alignment, index to data timing, write current, asymmetry and threshold dropout can be electronically adjusted. A plurality of programs stored in random access memory run a plurality of adjustment procedures used to control the electronic adjustment functions of the disk drive. An alignment disk read by the disk drive provides alignment data for the radial, track zero and index to data alignment procedures. A microstepper circuit in the disk drive allows the read/write heads to be moved in discrete steps of approximately 1/126 of the track pitch for electronically adjusting the radial and track zero parameters. The index to data alignment is set by generating and storing an artifical index offset value. The write current and asymmetry adjustment procedures utilize digital to analog convertors (DACS) to vary the voltage supplied to the read/write heads. The threshold dropout procedure utilizes a DAC to control the output of a pulse detector.

## Claims

### Claim 1

An electronically alignable floppy disk drive comprising:
a first transducer means for reading and writing information on a magnetic alignment disk recorded along with a plurality of concentric data tracks;
a transducer positioning means for moving the first transducer means relative to the magnetic disk in microstep increments of less than the distance separating adjacent concentric data tracks;
an envelope detector means for generating an analog data signal from information read by said first transducer means; and
a system control means for;
controlling said transducer positioning means to position said first transducer means such that said first transducer means is correctly positioned relative to at least one of the concentric data tracks of the magnetic alignment disk to optimize the analog data signal read from the magnetic alignment disk for an alignment parameter; and
storing data pertaining to the quantity and direction of the microstep increments required to so correctly position said first transducer relative to the magnetic alignment disk such that, when the magnetic alignment disk is removed from the floppy disk drive and a conventional floppy disk substituted therefor, said system control means can use the data to again position said first transducer means such that said first transducer means is positioned relative to the conventional floppy disk in like orientation as when said first transducer means was previously positioned relative to the magnetic alignment disk using the analog data signal obtained from the magnetic alignment disk, wherein;
said alignment parameter is the radial alignment of the first transducer means; and
said system control means determines the correct position for said first transducer means relative to a radial alignment track of the magnetic alignment disk by slaving said transducer positioning means in microstep increments until the envelope of a first lobe of a radial alignment signal is equal in magnitude to a second lobe of the radial alignment signal, the radial alignment signal being the analog data signal read by said first transducer means from the radial alignment track.

### Claim 2 (depends on 1)

The electronically alignable disk drive of claim 1 wherein,
the envelope detector means comprises an operational amplifier.

### Claim 3 (depends on 1)

The self-aligning disk drive of claim 1 further comprising:
an analog to digital conversion means connected to the envelope detector means for converting said analog data signal to a digital signal; and
a write current adjustment means for electronically adjusting the write current applied to the first transducer means.

### Claim 4 (depends on 3)

The electronically adjustable disk drive of claim 3 wherein, the write current adjustment means comprises a digital to analog convertor.

### Claim 5 (depends on 1)

The electronically adjustable disk drive of claim 1 wherein,
the system control means includes at least one computer program stored on a random access memory (RAM) chip.