Method of altering a computer operating system to boot and run from protected media

• US 6,993,649 B2
• Filed: 12/17/2002
• Issued: 01/31/2006
• Est. Priority Date: 12/17/2002
• Status: Expired due to Term

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: John Alan Hensley
• Inventors: Hensley, John Alan
• Primary Examiner(s): Browne, Lynne H.
• Assistant Examiner(s): YANCHUS III, PAUL B
• Application Number:
  US10/321,772
• Publication Number:
  US 20040117610A1
• Time in Patent Office: 1,141 Days
• Field of Search: 713/1, 713/2, 713/100, 707/200, 707/204, 703/23, 703/24, 703/25
• US Class Current: 713/2
• CPC Class Codes: G06F 21/57 Certifying or maintaining trusted computer platforms, e.g. secure boots or power-downs, version controls, system software checks, secure updates or assessing vulnerabilities
• CPC Class Codes: G06F 9/4406 Loading of operating system

Abstract

A modern computer operating system is altered to boot and run from a protected medium such as a CD-ROM. Files and configuration information are copied from a fully configured and operational OS to a hard drive image file. File system filters and device drivers are added that implement an emulated read-write hard disk drive by servicing initial read requests from the image file, and write requests and read requests to previously written data, from a written disk sector database. The OS is altered to load the filters and drivers during boot, and to subsequently run from the emulated read-write hard disk drive. The hard drive image file is then placed on a bootable protected medium.

Claims

1. A method of creating a bootable hard drive image file, comprising

copying files and configuration information from a fully configured and operational operating system to a hard drive image file;

copying to said hard drive image file a written disk sector database driver operative to create and maintain a written disk sector database of a predetermined maximum size equal to the size of all read-write files and free space in said hard drive image file;

copying to said hard drive image file a read-only protection driver operative to fail requests to write, delete or change file access attributes of read-only files; and

altering said files and configuration information on said hard drive image file such that the operating system will load said written disk sector database driver and said read-only protection driver during booting.

2. The method of claim 1 further comprising:

copying to said hard drive image file a file access request redirection driver operative to redirect write requests directed to read-write files or free space, and read requests directed to previously written files, to said written disk sector database, and

wherein altering said files and configuration information includes directing the operating system to load said file access request redirection driver.

3. The method of claim 2 wherein said file access request redirection driver passes read requests directed to files not previously written, to said hard drive image file.

4. The method of claim 1 further comprising placing said hard drive image file on a protected medium.

5. A method of altering the operating system of a computer to boot and run from a protected medium, comprising:

creating a hard drive image file;

copying files and configuration information from a fully configured and operational operating system to said hard drive image file;

copying a written disk sector database driver to said hard drive image file, said written disk sector database driver operative to create and maintain a written disk sector database of a predetermined maximum size equal to the size of all read-write files and free space in said hard drive image file;

copying a read-only protection driver to said hard drive image file, said read-only protection driver operative to fail requests to write, delete, or change file access attributes of read-only files;

altering said files and configuration information on said hard drive image file so that the operating system will load said written disk sector database driver and said read-only protection driver during booting, and

placing said hard drive image file on a protected medium.

6. The method of claim 5 further comprising:

copying a file access request redirection driver to said hard drive image file, said file access request redirection driver operative to redirect write requests directed to read-write files or free space, and read requests directed to previously written files, to said written disk sector database, and

wherein altering said files and configuration information includes directing the operating system to load said file access request redirection driver.

7. The method of claim 6 wherein said file access request redirection driver passes read requests directed to files not previously written, to said hard drive image file.

8. The method of claim 5 further comprising copying user files and configuration information to said hard drive image file.

9. The method of claim 5 wherein said protected medium is read by a device recognized by the computer as a bootable device.

10. The method of claim 5 further comprising, prior to said hard drive image file on a protected medium, testing the altered operating system by:

configuring said altered operating system to boot from a hard disk;

re-booting said computer from said hard disk using said altered operating system; and

executing at least one test script to test said altered operating system.

11. The method of claim 5 wherein said fully configured and operational operating system does not support running from a protected medium.

12. A protected computer readable medium including hard drive image file and an altered operating system created by altering a fully configured and operational operating system, said altered operating system operative to cause the computer to perform the following steps during booting:

creating an emulated read-write hard disk drive and attaching said drive to the file system as a physical drive;

creating and maintaining a written disk sector database of a predetermined maximum size equal to the size of all read-write files and free space on said emulated read-write hard disk drive, said written disk sector database operative to store write data directed to said emulated read-write hard disk drive; and

installing a read-only protection file system filter operative to fail requests to write, delete, or change file access attributes of read-only files.

13. The protected medium of claim 12 wherein said altered operating system further causes the computer to perform the following step during booting:

installing a redirection file system filter operative to redirect write requests directed to read-write files or free space, and read requests directed to previously written files, to said written disk sector database.

14. The protected medium of claim 13 wherein said altered operating system further causes the computer to perform the following steps during operation:

redirecting write requests to said emulated read-write hard disk drive that are directed to read-write files or free space, and read requests that are directed to previously written files, to said written disk sector database;

redirecting read requests to said emulated read-write hard disk drive that are directed to files not previously written to said hard drive image file on said protected medium; and

failing requests directed to said emulated read-write hard disk drive to write, delete, or change file access attributes of read-only files.

15. The protected medium of claim 12 wherein said altered operating system does not require a license separate from said fully configured and operational operating system.

16. The protected medium of claim 12 wherein said medium'"'"'s contents are prepared and placed on said medium by an end user.

17. The protected medium of claim 12 further including configuration information specific to the user.

18. The protected medium of claim 17 wherein said specific configuration information is selected from the group including network access configuration information, passwords, cryptographic keys, digital signatures, program configuration settings, and file system backup schedules.

19. A method of computer disaster recovery, comprising:

prior to loss of use of a computer system drive, preparing a protected medium containing an altered operating system derived from a fully configured and operational operating system, and including at least one device driver to emulate a read-write hard disk drive; and

following loss of use of said system drive, booting said computer from said protected medium and running said altered operating system on an emulated read-write hard disk drive comprising a written disk sector database of a predetermined size equal to all read-write files and free space on said emulated drive and a protection driver operative to fail requests to write, delete or change the read-only attributes of read-only files on said emulated drive.

20. The method of claim 19 wherein another said device driver comprises file access request redirection driver operative to redirect write requests directed to read-write files or free space, and read requests directed to previously written files, to said written disk sector database.

21. The method of claim 20 wherein said file access request redirection driver passes read requests directed to files not previously written, to said protected medium.

22. The method of claim 19 further comprising testing said altered operating system prior to placing it on said protected medium.

23. The method of claim 22 wherein said testing comprises rebooting said computer with said altered operating system and executing at least one test script, prior to placing said altered operating system on said protected medium.

24. The method of claim 19 wherein said fully configured and operational operating system does not natively run from said protected medium.

25. A method of booting and running a computer, whose primary operating system does not natively support running from protected media, from a protected medium, comprising:

copying said primary operating system files and configuration information to create a duplicate operating system;

creating file system filters and device drivers to emulate a read-write hard disk drive using a hard drive image file on a protected medium and a written disk sector database of a fixed maximum size equal to the size of all read-write files and free space on the emulated read-write hard disk drive;

altering said duplicate operating system to load and execute said file system filters and device drivers;

placing said altered operating system and said file system filters and device drivers on a protected medium; and

booting and running said computer with said altered operating system from said protected medium.

26. The method of claim 25 wherein when running, said altered operating system runs on said emulated read-write hard disk drive.

27. The method of claim 26 wherein said emulated read-write hard disk drive operates by servicing initial read requests from said protected medium and servicing write requests and read requests to previously written data from said written disk sector database.

28. The method of claim 27 wherein said emulated read-write hard disk drive preserves the read-only characteristics of files on said protected medium by failing requests to write, delete, or alter the file access attributes of read-only files on said protected medium.

29. The method of claim 25 wherein booting and running said computer with said altered operating system from said protected medium does not require ROMBIOS interrupt 0×

13 access following an initial operating system bootstrap phase.