Browse Prior Art Database

Wrong Data Writing Prevention Method in Hard Disk Drive Against Power Supply Noise of Personal Computer System

IP.com Disclosure Number: IPCOM000116455D
Original Publication Date: 1995-Sep-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Amano, Y: AUTHOR [+4]

Abstract

Disclosed is a method to prevent wrong data writing in a Hard Disk Drive (HDD) by sensing power supply noise.

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This is the abbreviated version, containing approximately 89% of the total text.

Wrong Data Writing Prevention Method in Hard Disk Drive Against Power
Supply Noise of Personal Computer System

      Disclosed is a method to prevent wrong data writing in a Hard
Disk Drive (HDD) by sensing power supply noise.

      Fig. 1 shows a simple circuit example to realize the idea.
This circuit consists of an FET, a comparator, a capacitor and
registers.  The circuit senses the power supply noise and issues an
error signal to stop the writing operation.  By using an FET and a
capacitor C1, it is possible to sense the noise in some frequency
range.  If the noise is over the criteria which is set with R9-R12,
the comparator issues the error signal to an HDD controller IC.  Then
the controller stops the writing operation.

Fig. 2 shows voltage wave forms on some points in the circuit.
  o  Wave form 1 shows the noise on the Vcc line.
  o  Wave form 2 shows the noise on the point '2'.
  o  Wave form 3 shows relation between the upper limit V4 ,the lower
      limit V5, the bias voltage V6 and the noise on the point '3'.
  o  Wave form 4 shows the error signal to the HDD controller IC.
The
      error signal 'LOW' means that the noise is over the criteria.
  o  Wave form 5 shows the write gate signal from the HDD controller
      IC.  The write gate signal 'LOW' means that the writing
operation
      is inhibited.  If the noise is over this voltage range from V4
to
      V5, the comparator issues the error signal 'LOW' an...