Computer system and method for accessing a protected partition of a disk drive that lies beyond a limited address range of a host computer's BIOS

• US 6,691,213 B1
• Filed: 02/28/2001
• Issued: 02/10/2004
• Est. Priority Date: 02/28/2001
• Status: Expired due to Term

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Western Digital Ventures Incorporated (Western Digital Corporation)
• Inventors: Luu, Vu V., Vallis, Mark F.
• Primary Examiner(s): Padmanabhan, Mano
• Assistant Examiner(s): Li, Zhuo H
• Application Number:
  US09/796,915
• Time in Patent Office: 1,077 Days
• Field of Search: 711/4, 711/163, 711/166, 711/164-165, 711/201, 713/2, 713/200, 713/1, 713/100, 710/10, 710/8
• US Class Current: 711/163
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 9/4406 Loading of operating system

Abstract

The invention may be embodied in a method and a related computer system. The computer system includes a host computer with a native drive-access routine having a limited address range, and a disk drive with a protected area that is inaccessible to a user'"'"'s preferred operating system. The protected area also lies beyond the limited address range. The method includes receiving and detecting a command in the disk drive for reading a master boot record to initiate a bootload of the operating system. In response to detecting the command, the method includes transferring a drive-selected master boot record that, when executed in the computer system, initiates a process that enables address spoofing, loads an extended-address drive-access routine from the protected area using spoofed addresses within the limited address range, and executes the extended-address drive-access routine to replace the native drive-access routine for providing access to the protected area.

Claims

1. In a computer system including a host computer with a native drive-access routine having an address range, and including a disk drive with a user area having data sectors that are accessible to a user'"'"'s preferred operating system and a protected area having data sectors that are inaccessible to the user'"'"'s preferred operating system, a method for accessing data sectors of the protected area having addresses that lie beyond the address range of the native drive-access routine, the method comprising:

receiving a command in the disk drive for reading a master boot record for the user'"'"'s preferred operating system to initiate a bootload of the user'"'"'s preferred operating system; and

detecting the command in the disk drive and, in response to detecting the command, transferring a drive-selected master boot record that, when executed in the computer system, initiates a process that;

enables address spoofing in the disk drive,

loads an extended-address disk-access routine from the protected area using spoofed addresses associated with data sectors that lie within the address range of the native drive-access routine, and

executes the extended-address disk-access routine to replace the native drive-access routine for providing access to data sectors having addresses that lie within the protected area.

2. A method for accessing protected-area data sectors as defined in claim 1, wherein the process initiated by the drive-selected master boot record further disables address spoofing after the extended-address disk-access routine is loaded from the protected area.

3. A method for accessing protected-area data sectors as defined in claim 1, wherein the disk drive performs address spoofing by accessing data from a predetermined spoof data, sector having an address that lies within the protected area in response to a host computer request for data from a target data sector having an address that lies within the address range of the native drive-access routine.

4. A method for accessing protected-area data sectors as defined in claim 1, wherein the extended-address disk-access routine has an address range that includes addresses for data sectors that lie within the protected area.

5. A method for accessing protected-area data sectors as defined in claim 1, wherein the native drive-access routine is an interrupt routine of a basic input output system (BIOS) of the host computer.

6. A method for accessing protected-area data sectors as defined in claim 1, wherein address spoofing comprises having the disk drive substitute host-requested data from a sector having a target logical block address that lies within the address range of the native drive-access routine with drive-selected data from a sector having a logical block address that lies beyond the address range of the native drive-access routine.

7. A method for accessing protected-area data sectors as defined in claim 1, wherein the command in the disk drive for reading the master boot record for the user'"'"'s preferred operating system is issued by the host computer for reading a host-computer-selected master boot record for the user'"'"'s preferred operating system.

8. A computer system, comprising:

a host computer having a native drive-access routine having an address range;

a disk drive having a user area including data sectors that are accessible to a user'"'"'s preferred operating system and a protected area including data sectors that are inaccessible to the user'"'"'s preferred operating system and that lie beyond the address range of the native drive-access routine;

means for receiving a command in the disk drive for reading a master boot record for the user'"'"'s preferred operating system to initiate a bootload of the user'"'"'s preferred operating system;

means for detecting the command in the disk drive and, in response to detecting the command, transferring a drive-selected master boot record; and

means for executing the drive-selected master boot record in the computer system to initiate a process that;

enables address spoofing in the disk drive,

loads an extended-address disk-access routine from the protected area using spoofed addresses associated with data sectors that lie within the address range of the native drive-access routine, and

executes the extended-address disk-access routine to replace the native drive-access routine thereby providing access to data sectors having addresses that lie within the protected area.

9. A computer system as defined in claim 8, wherein the disk drive performs address spoofing by accessing data from a predetermined spoof data sector having an address that lies within the protected area in response to a host computer request for data from a target data sector having an address that lies within the address range of the native drive-access routine.

10. A computer system as defined in claim 8, wherein the extended-address disk-access routine has an address range that includes addresses for data sectors that lie within the protected area.

11. A computer system as defined in claim 8, wherein the native drive-access routine is an interrupt routine of a basic input output system (BIOS) of the host computer.

12. A computer system as defined in claim 8, wherein address spoofing comprises having the disk drive substitute host-requested data from a sector having a target logical block address that lies within the address range of the native drive-access routine with drive-selected data from a sector having a logical block address that lies beyond the address range of the native drive-access routine.

13. A computer system as defined in claim 8, wherein the command in the disk drive for reading the master boot record for the user'"'"'s preferred operating system is issued by the host computer for reading a host-computer-selected master boot record for the user'"'"'s preferred operating system.