Browse Prior Art Database

Technique for Data Protection From Normal Users

IP.com Disclosure Number: IPCOM000100532D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Nakagawa, Y: AUTHOR [+3]

Abstract

Described herein is a technique to protect a certain portion of data area on a disk file from normal users. This technique was proposed to move ROM data on a personal computer system to the disk file. (This ROM usually contains a system program.) By this technique, the user can reduce the cost of ROM while increasing the system flexibility.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 64% of the total text.

Technique for Data Protection From Normal Users

       Described herein is a technique to protect a certain
portion of data area on a disk file from normal users.  This
technique was proposed to move ROM data on a personal computer system
to the disk file.  (This ROM usually contains a system program.)  By
this technique, the user can reduce the cost of ROM while increasing
the system flexibility.

      The technique is realized by introducing "SET MAX RBA" command.
 This command allows a system level program to change the maximum
allowable block address for all subsequent normal user requests.

      Two options are given to this newly introduced command, "SET
MAX RBA".  One is to modify the maximum allowable block address
temporarily, and the other is permanently.  A typical case of the use
of the command is as follows:

      (a) During a system installation, a system programmer uses "SET
MAX RBA" to change the maximum allowable block address to the
absolute maximum.  This process can be achieved by "FORMAT" command
as well.  FORMAT command always uses the absolute maximum to clean up
the entire disk.

      (b) Install the system program onto the high-end address of the
disk, where the normal user cannot access.

      (c) Send "SET MAX RBA" command to change the maximum allowable
block address permanently.  This value is saved into a disk
configuration area which is not accessible from the system.  From
this moment, a disk control pr...