Persci, Inc.

Robert W Erickson, Sr

G Randall Stevens

A disk drive for one or more spinning disks has a voice coil motor, driving the transducer carriage and controlled by two feedback loops, respectively, for hold and seek modes and enabled by a microcomputer which is additionally inserted into the seek mode feedback loop. The microcomputer receives step pulses from a controller host as well as detent pulses through a path of that seek loop; the pulses serve as interrupts and the microcomputer selects digital speed signals on the basis of step and detect pulse counts. An a/d converter inserts that signal as command into the seek loop. The microcomputer performs basically a continuous loop type of program pursuant to which command (select) lines from the host are interrogated and the hold mode is maintained until, for example, one or more step pulses interrupt this program loop to command the drive to move the carriage to another track; the microcomputer then shifts the drive to the seek mode, which is maintained by the continuous loop until the carriage has arrived at the new position. Special subroutines cause the drive to center on a zero track when externally or internally commanded. A variety of diagnostic tests can be performed.

Disk drive system

The disc file system being improved includes a motor driven transducer carriage for positioning the transducer in selected cylinder positions. A command unit issues step pulses and the carriage provides detent pulses respectively representing the number of tracks (cylinders) to be and being crossed when the carriage is caused to move and moves from one cylinder position to another one. These pulses are processed so that overlap is avoided in that following the trailing edge of each step or detent pulse, a process pulse, is produced either with or without delay depending on the need to avoid conflict. The process pulses to be produced are up an down counted for tracking actual carriage movement, and the total count is zero when the carriage has arrived at the desired position.

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Pacific Palisades, CA, United States of America

Robert W Erickson, Sr