Data storage device having multiple heads traveling in opposite directions for capacity and throughput optimization

• US 6,658,201 B1
• Filed: 06/24/1999
• Issued: 12/02/2003
• Est. Priority Date: 06/24/1999
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Rebalski, Jan F.
• Primary Examiner(s): BOCCIO, VINCENT F
• Application Number:
  US09/339,773
• Time in Patent Office: 1,622 Days
• Field of Search: H04/N.591, 386/125-126, 386/95, 386/96, 386/105, 386/122, 386/98, 369/124.09, 369/44.37
• US Class Current: 386/253
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 27/105 of operating discs
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence
• CPC Class Codes: G11B 5/4886 relative to rotating disc
• CPC Class Codes: G11B 7/0045 Recording G11B7/006, G11B7/0065 take precedence
• CPC Class Codes: G11B 7/005 Reproducing G11B7/0065 takes precedence
• CPC Class Codes: G11B 7/14 specially adapted to record on, or to reproduce from, more than one track simultaneously

Abstract

Methods and systems for improving the storage capacity and data throughput of a digital mass storage device. The novel optimizations can be applied to a disk drive, either a hard disk drive or a disk drive having removable media, such as magnetic and optical disk drive technologies. The present invention provides at least two disk drive heads for reading and writing information from two different spinning media surfaces, e.g., platters or disks. If the disk is a read-only device, then the heads only perform the read function. A constant angular velocity drive mechanism is used meaning the rotational speed of the media is constant regardless of the head'"'"'s position with respect to the media. In operation, during a media transfer, the first head accesses data by starting at the outside regions (“high track rates”) of the disk media and traversing inward towards the inner regions (“low track rates”). The second head, moving the opposite direction but in synchronization with the first head, starts accessing data in the inner regions of its disk media and traverses towards the outer regions. A data file is portioned and its portions are accessed using both heads combined to provide a uniform and high data throughput. The sectors are specially mapped and the data is interleaved to provide a maximum throughput. Capacity is increased because much, if not all, of the inner regions of the disk media are used in the present invention while still maintaining a high and uniform data throughput.

Claims

1. A digital storage device comprising:

a first disk media comprising a single storage area;

a second disk media comprising a single storage area;

a first head for writing digital data on a plurality of tracks of said first disk media, said first head moving across said single storage area of said first disk media in a first direction;

a second head for writing digital data on a plurality of tracks of said second disk media, said second head moving across said single storage area of said second disk media in a second direction opposite to said first direction; and

a multiplexer circuit for receiving a digital data stream and for supplying first portions of said digital data stream to said first head and second portions of said digital data stream to said second head, wherein respective size ratios of respective first and second portions are based on corresponding track position ratios of said first and second heads.

2. The digital storage device as described in claim 1 wherein said first head and said second head write digital data with a substantially constant combined data throughput rate as a result of said respective size ratios.

3. The digital storage device as described in claim 2 wherein said first direction of said first head is from an outer one of said plurality of tracks to an inner one of said plurality of tracks of said first disk media and wherein said second direction of said second head is from an inner one of said plurality of tracks to an outer one of said plurality of tracks of said second disk media.

4. The digital storage device as described in claim 2 further comprising a memory unit having stored therein a look up table and wherein said look-up table corresponds said respective size ratios to said associated track position ratios and wherein an output of said memory unit controls said multiplexer circuit.

5. The digital storage device as described in claim 2 further comprising a mechanism for spinning said first and second disk media at a constant angular velocity.

6. The digital storage device as described in claim 2 wherein said first disk media and said second disk media are magnetic disk platters.

7. The digital storage device as described in claim 2 wherein said first disk media and said second disk media are optical disks.

8. The digital storage device as described in claim 2 wherein said digital data stream represents audio/video (AV) information.

9. A digital storage device comprising:

a first disk media comprising a first surface and a second surface, said first surface comprising a single storage area and said second surface comprising a single storage area;

a second disk media comprising a first surface and a second surface, said first surface comprising a single storage area and said second surface comprising a single storage area;

a first head coupled to a first actuator and for writing digital data on a plurality of tracks of said first disk media, said first head moving across said single storage area of said first surface of said first disk media in a direction from an outer one of said plurality of tracks to an inner one of said plurality of tracks;

a second head coupled to a second actuator and for writing digital data on a plurality of tracks of said first disk media, said second head moving across said single storage area of said second surface of said first disk media in a direction from an inner one of said plurality of tracks to an outer one of said plurality of track;

a third head coupled to said first actuator and for writing digital data on a plurality of tracks of said second disk media, said third head moving across said single storage area of said first surface of said second disk media in a direction from an outer one of said plurality of tracks to an inner one of said plurality of tracks;

a fourth head coupled to said second actuator and for writing digital data on a plurality of tracks of said second disk media, said fourth head moving across said single storage area of said second surface of said second disk media in a direction from an inner one of said plurality of tracks to an outer one of said plurality of tracks; and

a multiplexer circuit for receiving a digital data stream and for supplying first portions of said digital data stream to said first and third heads and second portions of said digital data stream to said second and fourth heads, wherein respective size ratios of respective first and second portions are based on corresponding track position ratios of said first and second heads.

10. The digital storage device as described in claim 9 wherein said first, second, third and forth heads write digital data with a substantially constant combined data throughput rate as a result of said respective size ratios.

11. The digital storage device as described in claim 10 further comprising a memory unit having stored therein a look up table wherein said look-up table corresponds said respective size ratios to said associated track position ratios and wherein an output of said memory unit controls said multiplexer circuit.

12. The digital storage device as described in claim 10 further comprising a mechanism for spinning said first and second disk media at a constant angular velocity.

13. The digital storage device as described in claim 10 wherein said first disk media and said second disk media are magnetic disk platters.

14. A digital storage device comprising:

a first disk media comprising a first surface and a second surface, said first surface comprising a single storage area and said second surface comprising a single storage area;

a second disk media comprising a first surface and a second surface, said first surface comprising a single storage area and said second surface comprising a single storage area;

a first head coupled to a first actuator and for reading digital data off of a plurality of tracks of said first disk media, said first head moving across said single storage area of said first surface of said first disk media in a direction from an outer one of said plurality of tracks to an inner one of said plurality of tracks;

a second head coupled to a second actuator and for reading digital data off of a plurality of tracks of said first disk media, said second head moving across said single storage area of said second surface of said first disk media in a direction from an inner one of said plurality of tracks to an outer one of said plurality of tracks;

a third head coupled to said first actuator and for reading digital data off of a plurality of tracks of said second disk media, said third head moving across said single storage area of said first surface of said second disk media in a direction from an outer one of said plurality of tracks to an inner one of said plurality of tracks;

a fourth head coupled to said second actuator and for reading digital data off of a plurality of tracks of said second disk media, said fourth head moving across said single storage area of said second surface of said second disk media in a direction from an inner one of said plurality of tracks to an outer one of said plurality of tracks; and

a demultiplexer circuit for receiving said digital data from said first, second, third and fourth heads and for supplying a single digital data stream therefrom wherein digital data is supplied from said first, second, third and fourth heads at a combined throughput rate that is substantially constant.

15. The digital storage device as described in claim 14 wherein said single digital data stream represents audio/video (AV) information and further comprising a mechanism for spinning said first and second disk media at a constant angular velocity.

16. A method of storing digital data comprising the steps of:

a) receiving a digital data stream;

b) supplying first portions of said digital data stream to a first head and supplying second portions of said digital data stream to a second head, wherein respective size ratios of respective first and second portions are based on corresponding track position ratios of said first and second heads;

c) traversing tracks of a first disk media from outer tracks to inner tracks with said first head and writing said first portions onto tracks of said first disk media using said first head, wherein said first disk media comprises a single storage area;

d) traversing tracks of a second disk media from inner tracks to outer tracks with said second head and writing said second portions onto tracks of said second disk media using said second head, wherein said second disk media comprises a single storage area and wherein the combined data throughput of said first head plus said second head is substantially constant; and

e) spinning said first disk media and second disk media at a constant angular velocity.

17. The method as described in claim 16 wherein said step b) comprises the step of accessing a look up table stored in a memory unit to determine said respective size ratios wherein said look-up table corresponds said respective size ratios to said associated track position ratios.

18. The method as described in claim 16 wherein said first disk media and said second disk media are magnetic disk platters.

19. The method as described in claim 16 wherein said first disk media and said second disk media are optical disks.

20. The method as described in claim 16 wherein said digital data stream represents audio/video (AV) information.