Browse Prior Art Database

Method to Save the Drive in which a Bad U-Code was Down-Loaded

IP.com Disclosure Number: IPCOM000114463D
Original Publication Date: 1994-Dec-01
Included in the Prior Art Database: 2005-Mar-28
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Hashimoto, M: AUTHOR [+2]

Abstract

Proportion to the complicity of the recent drive mechanism and it's applications, the software in the drive becomes very sophisticated. To meet this complicated application, u-code were saved on the disk space to be up-loaded during power on. This allows to alter the control software to meet the unique user requirement after shipment.

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This is the abbreviated version, containing approximately 86% of the total text.

Method to Save the Drive in which a Bad U-Code was Down-Loaded

      Proportion to the complicity of the recent drive mechanism and
it's applications, the software in the drive becomes very
sophisticated.  To meet this complicated application, u-code were
saved on the disk space to be up-loaded during power on.  This allows
to alter the control software to meet the unique user requirement
after shipment.

      Current implementation of this Down Loading mechanism can not
prevent a bad u-code to be down-loaded.  Once the drive is
contaminated with this bad u-code, it requires fair amount of work to
recover, such as replacing ROM with a special one not to up-load
u-code at power up.  Then overwrite u-code on the disk by using a
program on this special Read Only Memory (ROM).  This method can
eliminate this physical operation.  The method is shown in the
Figure.

Include the following mechanism in the bootstrap ROM on the drive:
  1.  Before giving a control to the up-loaded u-code, checks if a
host
       is requesting to stop the bootstrap operation.  This request
is
       sent through the normal interface between the drive and the
host.
  2.  If the above is TRUE, ROM code waits for a next request from
the
       host.  A control will not be given to the up-loaded u-code.
  3.  The host can send a Down-Load command to overwrite the bad
u-code
       with the new one.

Prepare the following special routine at the host:
  1.  Se...