Host-based virtual disk drive for improving the performance of a hard disk drive's input/output

• US 6,490,651 B1
• Filed: 03/14/2000
• Issued: 12/03/2002
• Est. Priority Date: 03/14/2000
• Status: Expired due to Term

• Current Assignee: Maxtor Corporation (Seagate Technology Holdings Plc)
• Original Assignee: Maxtor Corporation (Seagate Technology Holdings Plc)
• Inventors: Bagachev, Iouri, Shats, Serge, Schlumberger, Maurice, Camp, Claude
• Primary Examiner(s): Yoo, Do Hyun
• Assistant Examiner(s): Namazi, Mehdi
• Application Number:
  US09/525,727
• Time in Patent Office: 994 Days
• Field of Search: 711/112-114, 710/8, 369/48
• US Class Current: 711/112
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0664 at device level, e.g. emulation of a storage device or system
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

Software executing in a hard disk drive'"'"'s host computer system increases the perceived efficiency and performance of the hard disk drive. The host computer system implements a “virtual disk” that models physical parameters associated with the actual hard disk drive, such as seek time and physical location of the read/write heads. These parameters are used to implement host based disk drive optimization techniques such as command reordering and read-on-arrival commands.

Claims

1. A computer system comprising:

a hard disk drive;

a random access memory, the random access memory storing operating system data and user data;

a virtual disk implemented in the random access memory, the virtual disk modeling physical parameters of the hard disk drive; and

a processor coupled to the random access memory and the hard disk drive, the processor executing instructions from the random access memory and optimizing data requests to the hard disk drive based on the physical parameters modeled by the virtual disk.

2. The computer system of claim 1, wherein the virtual disk models a hard disk drive seek time.

3. The computer system of claim 1, wherein the virtual disk models a head position of the hard disk drive.

4. The computer system of claim 1, wherein the processor optimizes data requests to the hard disk drive by performing command reordering.

5. The computer system of claim 1, wherein the random access memory further includes a hard disk drive cache.

6. The computer system of claim 5, wherein the processor optimizes data requests to the hard disk drive by converting read commands to read-on-arrival commands.

7. The computer system of claim 1, wherein the virtual disk is implemented as a part of the operating system.

18. The computer system of claim 1, wherein the physical parameters are modeled using at least one of time seek profile, physical zone table, inline defects and spare sectors, read-to-write and write-to-read switch time, and software and firmware overheads.

19. The computer system of claim 1, wherein the physical parameters are modeled using a starting and an ending logical block address.

20. The computer system of claim 1, wherein the processor optimizes data requests to the hard disk drive using an optimized reordering command algorithm.

8. A method for optimizing perceived performance of a hard disk drive, the method comprising:

forming a virtual disk in a host computer including modeling physical parameters of the hard disk drive at a location in a random access memory external to the hard disk drive; and

optimizing data requests from the random access memory to the hard disk drive base on the modeled physical parameters of the virtual disk.

9. The method of claim 8, wherein the modeling of physical parameters includes modeling hard disk drive seek time.

10. The method of claim 8, wherein the modeling of physical parameters includes modeling head position of the hard disk drive.

11. The method of claim 8, wherein the optimization of data requests to the hard disk drive is implemented by command reordering.

12. The method of claim 8, wherein the optimization of data requests to the hard disk drive is implemented by converting read commands to read-on-arrival commands.

21. The method of claim 8, wherein modeling physical parameters comprises using parameters including at least one of time seek profile, physical zone table, inline defects and spare sectors, read-to-write and write-to-read switch time, and software and firmware overheads.

22. The method of claim 8, wherein modeling physical parameters comprises using parameters including a starting logical block address and an ending logical block address.

23. The method of claim 8, wherein modeling physical parameters comprises synchronizing a calculated position of the drive head with an actual position of the drive head.

24. The method of claim 8, wherein modeling physical parameters comprises implementing an optimized reordering command algorithm.

25. The method of claim 8, wherein modeling physical parameters comprises performing a command reordering using a shortest seek time-first ordering method.

26. The method of claim 8, wherein modeling physical parameters comprises performing a command reordering using an elevator seeking method.

27. The method of claim 8, wherein optimizing of data requests to the hard disk drive is implemented by converting read commands to read-on-arrival commands including:

calculating a sector that a hard disk drive head will be positioned over when the hard disk drive lands at its intended landing position to read data requested by an application;

altering read commands by a hard disk drive interface to begin reading at said secotor;

reading data by the hard disk drive;

returning both data requested by the application and data stored in sectors between the landing position of the hard disk drive and the start of the data request; and

returning only requested data to the application.

13. A machine readable medium, the machine readable medium when read by a machine performing:

forming in a random access memory external to a hard disk drive a representation of a virtual disk comprising modeling physical parameters of the hard disk drive; and

optimizing data requests from the random access memory to the hard disk drive base on the modeled physical parameters of the virtual disk.

14. The machine readable medium of claim 13, wherein the modeling of physical parameters includes modeling hard disk drive seek time.

15. The machine readable medium of claim 13, wherein the modeling of physical parameters includes modeling head positions of the hard disk drive.

16. The machine readable medium of claim 13, wherein the optimizing of data requests to the hard disk drive is implemented by command reordering.

17. The machine readable medium of claim 13, wherein the optimizing of data requests to the hard disk drive is implemented by converting read commands to read-on-arrival commands.

28. The machine readable medium of claim 13, wherein modeling physical parameters comprises using parameters including at least one of time seek profile, physical zone table, inline defects and spare sectors, read-to-write and write-to-read switch time, and software and firmware overheads.

29. The machine readable medium of claim 13, wherein modeling physical parameters comprises using parameters including a starting logical block address and an ending logical block address.

30. The machine readable medium of claim 13, wherein modeling physical parameters comprises synchronizing a calculated position of the drive head with an actual position of the drive head.

31. The machine readable medium of claim 13, wherein modeling physical parameters comprises implementing an optimized reordering command algorithm.

32. The machine readable medium of claim 13, wherein modeling physical parameters comprises performing a command reordering using a shortest seek time-first ordering method.

33. The machine readable medium of claim 13, wherein modeling physical parameters comprises performing a command reordering using an elevator seeking method.

34. The machine readable medium of claim 13, wherein optimizing of data requests to the hard disk drive is implemented by converting read commands to read-on-arrival commands including:

calculating a sector that a hard disk drive head will be positioned over when the hard disk drive lands at its intended landing position to read data requested by an application;

altering read commands by a hard disk drive interface to begin reading at said sector;

reading data by the hard disk drive;

returning both data requested by the application and data stored in sectors between the landing position of the hard disk drive and the start of the data request; and

returning only requested data to the application.