Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

File Erase Test Compensation to Control Squeeze

IP.com Disclosure Number: IPCOM000120564D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Cunningham, EA: AUTHOR

Abstract

Disclosed is a method that allows a rapid measurement approximating the performance write width of each head/disk combination in a direct access storage device (DASD) and thus allows the adjustment of the write current for each combination in order to compensate for the variation of many of the head/disk parameters that affect the write width. This allows a better performance or additional capacity to be achieved.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

File Erase Test Compensation to Control Squeeze

      Disclosed is a method that allows a rapid measurement
approximating the performance write width of each head/disk
combination in a direct access storage device (DASD) and thus allows
the adjustment of the write current for each combination in order to
compensate for the variation of many of the head/disk parameters that
affect the write width. This allows a better performance or
additional capacity to be achieved.

      In the design of magnetic recording DASD, the performance type
of write width must be contained to a maximum width approximately
equal to the designed pitch of the DASD.  The write width varies with
the physical track width of the head, and multiple parameters
affecting the fringes written by the head, such as gap length, throat
height, and disk coercivity.

      It can be shown that for a given geometry of heads and disks,
and for a given recorded density, that the performance write width of
the head/disk combination can be approximated as the erase width of
the combination, plus a fixed width.  The fixed width to add is
determined with a few performance width tests on sample components.
Thus, a performance write width of any head/disk combination can be
mathematically projected from the measured erase width of the
head/disk combination.

      The erase width can be determined by writing a track with a
given frequency, measuring the amplitude, DC erasing with the head
offset a given amount in each direction,...