Browse Prior Art Database

Floppy Disk Drive Alignment Method

IP.com Disclosure Number: IPCOM000060450D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Eide, JF: AUTHOR [+5]

Abstract

A method is described for calibration of an alignment tester having a collet which mounts and spins a disk, having rails to mount and move a head carriage to specified track positions, and having a computer and program to measure movement of the carriage between tracks, by analysis of waveforms read from the disk. A head carriage of unknown head spacing is first mounted on the rails of the fixture. A laser interferometer is now mounted relative to the fixture, in a manner to measure the movement of the carriage. A disk is now installed on the fixture, and the fixture's carriage moving motor is used to position the carriage and its head at a specific disk track. A data pattern is then written on that track.

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Floppy Disk Drive Alignment Method

A method is described for calibration of an alignment tester having a collet which mounts and spins a disk, having rails to mount and move a head carriage to specified track positions, and having a computer and program to measure movement of the carriage between tracks, by analysis of waveforms read from the disk. A head carriage of unknown head spacing is first mounted on the rails of the fixture. A laser interferometer is now mounted relative to the fixture, in a manner to measure the movement of the carriage. A disk is now installed on the fixture, and the fixture's carriage moving motor is used to position the carriage and its head at a specific disk track. A data pattern is then written on that track. The head is now moved to another track, on the same side of the disk, again using the fixture's carriage moving motor, a second data pattern is written on this other track. The laser interferometer is used to determine the true distance moved between these two tracks. The carriage is now moved outboard of the two tracks which have been written. Thereafter, the carriage is moved inward, in small steps, while reading the disk, such that two substantially triangular amplitude versus position waveforms are produced. These two waveforms are now analyzed to determine the spacing between the two tracks from the centers of the two waveforms. A correcting factor can now be applied to the computer output, based upon any difference which may exist between the distance between the track, as indicated by the analysis of the two waveforms, and the interferometer. The now calibrated fixture can be used to determine the radial spacing of the two heads A and B of a double-sided head carriage intended for use in a floppy disk drive by installing the carriage in the spinner fixture, writing a test track on the disk with each head, as the carriage is held in one position, such that the disk thereafter contains two tracks A and B, written by heads A and B, respectively, on the opposite sides of the disk, the radial spacing of the tracks being the unknown spacing of the two heads, flippi...