Browse Prior Art Database

Write Function Verification at Power On Self Diagnosis

IP.com Disclosure Number: IPCOM000112404D
Original Publication Date: 1994-May-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Nakamura, T: AUTHOR [+2]

Abstract

Disclosed is a methodology to ensure the write function of Hard Disk Drive (HDD) which uses the Magneto Resistive / Inductive (MRI) head.

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This is the abbreviated version, containing approximately 100% of the total text.

Write Function Verification at Power On Self Diagnosis

      Disclosed is a methodology to ensure the write function of Hard
Disk Drive (HDD) which uses the Magneto Resistive / Inductive (MRI)
head.

      Since a MRI head has independent read (MR) and write
(Inductive) elements, the loss of write functions is not detected as
read or servo errors.  There must be some capabilities to detect
failures on write element and or supporting circuits.  In
conventional way, special circuits detect these failures.  Instead of
having those circuits, this disclosure provides an economical method
to detect most of such failures.

A. Function Verification at Power On Reset of HDD

1.  Seek to a test cylinder.

2.  Read data from one sector.

3.  Modify data read at (2).

4.  Write back that modified data into same sector.

5.  Read that sector again.

6.  Verify if the modification which was applied at (3) is correctly
    done.

7.  If the modification is not correct, set a flag to show WRITE
    FAULT status (WRITE FAULT FLAG).

The above sequence should be applied for all heads.

B. All write command should be terminated with an error status if the
WRITE FAULT FLAG is set.