System and method to enable a legacy BIOS system to boot from a disk that includes EFI GPT partitions

• US 20030014622A1
• Filed: 07/02/2002
• Published: 01/16/2003
• Est. Priority Date: 07/03/2001
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Larvoire, Jean-Francois
• Granted Patent: US 6,978,363 B2
• Time in Patent Office: Days
• US Class Current: 713/2
• CPC Class Codes: G06F 11/1417 Boot up procedures
• CPC Class Codes: G06F 9/441 Multiboot arrangements, i.e. selecting an operating system to be loaded

Abstract

A system and a method to boot from a modified GPT partitioned disk with a legacy BIOS based system. The system and method allows for backward compatibility with the new GPT standard. A GPT-aware bootstrap code may be loaded by the legacy BIOS upon system start up.

Claims

1. A system to enable a legacy BIOS based system to boot from a disk that includes EFI GPT partitions, comprising:

a master boot record including a GPT-aware boot strap code within the master boot record, wherein the GPT-aware boot strap code is loadable by the legacy BIOS;

a boot program area including at least one GPT boot program, wherein the at least one GPT program is executed prior to booting the legacy BIOS based system.

2. The system of claim 1, wherein the disk is one of a MBR+GPT hybrid disk and a modified legacy disk that includes a micro-GPT portion.

3. The system of claim 2, wherein the MBR-GPT hybrid disk is also bootable by an EFI-compliant BIOS system.

4. The system of claim 2, wherein the micro-GPT portion includes a relay partition, wherein the relay partition includes information about one or more of the GPT boot programs and operating systems stored outside the micro-GPT portion.

5. The system of claim 1, wherein the boot program area includes a plurality of GPT boot programs.

6. The system of claim 5, wherein each of the plurality of GPT boot programs resides in one of a GPT-managed area and a legacy partitioned area.

7. The system of claim 5, wherein the plurality of GPT boot programs form a chain of boot programs that are all executed prior to any operating system being loaded.

8. The system of claim 7, wherein each GPT boot program includes instructions to load a first sector of a next GPT boot program in the chain of boot programs.

9. The system of claim 8, wherein the each GPT boot program includes instructions to verify a validity of the next GPT boot program prior to relinquishing control to the next GPT boot program.

10. The system of claim 7, wherein a first sector of each GPT boot program includes instructions to load a remainder of the each GPT boot program.

11. The system of claim 7, wherein a last GPT boot program is a boot menu program.

12. The system of claim 5, wherein any of the plurality of GPT boot programs is replaceable by another GPT boot program.

14. The method of claim 13, further comprising:

loading a legacy boot system in response to the determining step providing a negative result or to the verifying step providing a negative result.

15. The method of claim 13, wherein a plurality of GPT boot programs exist, the method further comprising:

verifying a validity of each of the plurality of GPT boot programs prior to executing the each of the plurality of GPT boot programs.

16. The method of claim 15, wherein the step of verifying the validity comprises:

verifying a CRC of the each of the plurality of GPT boot programs.

17. The method of claim 16, further comprising:

loading the each of the plurality of GPT boot programs based on a positive result of the verifying the CRC step.

19. The system of claim 18, further comprising:

means for loading a legacy boot system in response to the means for determining providing a negative result or in response to the means for verifying providing a negative result.

20. The system of claim 18, wherein the means for verifying includes means for verifying a CRC of the at least one GPT boot program.

13. A method to enable a legacy BIOS based system to boot from a disk that includes modified EFI GPT partitions, comprising:

determining whether at least one GPT boot program exists;

verifying a validity of the at least one GPT boot program in response to the determining step providing a positive result;

executing the at least one GPT boot program in response the verifying step providing a positive result;

creating a boot menu of available systems; and

loading a selected system.

18. A system to enable a legacy BIOS based system to boot from a disk that includes EFI GPT partitions, comprising:

means for determining whether at least one GPT boot program exists;

means for verifying a validity of the at least one GPT boot program in response to the determining step providing a positive result;

means for executing the at least one GPT boot program in response the verifying step providing a positive result;

means for creating a boot menu of available systems; and

means for loading a selected system.