US 6,618,331 B2 · Method and apparatus for accessing target data in a data storage medium

Abstract

In a method and apparatus for accessing target data in a data storage medium, identification data in an initial data sector is verified before a target data sector that corresponds to starting location of the target data in the data storage medium can be found. Therefore, accuracy of the target data can be ensured before decoding of the target data is performed to result in increased efficiency and reduced idle time.

Drawings

Claims8

Dependent claims

A method for accessing target data in a data storage medium having sequentially arranged data sectors recorded therein, each of the data sectors containing at least identification data, an identification error detection code and main data, said method comprising:

(a) reading one of the data sectors recorded in the data storage medium;
(b) demodulating said one of the data sectors to generate a block unit that contains the identification data, the identification error detection code and the main data of said one of the data sectors, and that further contains an inner-code parity for the block unit;
(c) verifying accuracy of the identification data in the block unit;
(d) repeating steps (a), (b) and (c) for a succeeding one of the data sectors of the data storage medium when the identification data in the block unit is found to be inaccurate;
(e) finding a target data sector that corresponds to starting location of the target data in the data storage medium with reference to the block unit having accurate identification data;
(f) reading the data sectors recorded in the data storage medium in sequence starting from the target data sector;
(g) demodulating the data sectors read in step (f) to generate the block units that correspond thereto;
(h) storing the block units generated in step (g) in a data buffer to form a block;
and
(i) decoding the block formed in the data buffer.

7 more elements

An apparatus for accessing target data in a data storage medium having sequentially arranged data sectors recorded therein, each of the data sectors containing at least identification data, an identification error detection code and main data, said apparatus comprising:

a pick-up head adapted for reading one of the data sectors recorded in the data storage medium;
a demodulator coupled to said pick-up head and operable so as to demodulate said one of the data sectors to generate a block unit that contains the identification data, the identification error detection code and the main data of said one of the data sectors, and that further contains an inner-code parity for the block unit;
an error correction code decoder coupled to said demodulator and operable so as to verify accuracy of the identification data in the block unit, said error correction code decoder enabling said demodulator to generate the block unit for a succeeding one of the data sectors recorded in the data storage medium when the identification data in the block unit for a current one of the data sectors is found to be inaccurate;
said demodulator being under the control of said error correction code decoder to enable said pick-up head to find a target data sector that corresponds to starting location of the target data in the data storage medium with reference to the block unit having accurate identification data, and to read the data sectors recorded in the data storage medium in sequence starting from the target data sector;
said demodulator demodulating the data sectors from said pick-up head to generate the corresponding block units;
and
a data buffer coupled to said demodulator for storing the block units generated thereby to form a block in said data buffer;
said error correction code decoder being further coupled to said data buffer and being further operable so as to decode the block formed in said data buffer.

5 more elements

Dependencies are inferred from the claim text.

Description3,238 words

Summary1,241 words

#1. Field of the Invention

#The invention relates to a method and apparatus for accessing target data in a data storage medium, more particularly to a method and apparatus for facilitating fast and accurate access of target data in a data storage medium.

#2. Description of the Related Art

Brief description of the drawings5 figures

#Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:

#FIG. 1 is a block diagram illustrating a conventional digital versatile disk player;

#FIG. 2 is a block diagram illustrating a digital versatile disk player that embodies the method and apparatus of this invention;

Detailed description1,887 words

#Referring to FIG. 2, the method and apparatus of the present invention is suitable for fast and accurate access of target data in a data storage medium 20. The apparatus 2 that embodies the present invention serves as a bridge between the data storage medium 20 and a playback or host terminal (not shown) for reproducing the data recorded in the data storage medium 20. In this embodiment, the apparatus 2 is a digital versatile disk (DVD) player, and the data storage medium 20is an optical disk, such as a compact disk (CD), a video compact disk (VCD), or a digital versatile disk (DVD) . Referring to FIG. 3, in general, the data storage medium 20 has sequentially arranged data sectors 200 recorded therein.

#Each data sector 200 contains identification data (ID) 201, an identification error detection (IED) code 202, main data 203, and an error detection code (EDC/CRC) 204. Ideally, the identification data 201 contains a sector code unique to the data sector 200. The IED code 202 is used to validate the identification data 201 to verify the presence of any errors therein.

#Referring once again to FIG. 2, the apparatus 2 includes a pick-up head 200, a demodulator 21 coupled to the pick-up head 200, a data buffer 22, an error correction code (ECC) decoder 23, a descrambler and error detection code (EDC) checker 26, an advanced technology attachment packet interface (ATAPI) 27, and a multiplexer 28. When accessing data in the data storage medium 20, the apparatus 2 first has to find a target data sector that corresponds to starting location of the target data in the data storage medium 20. To this end, the apparatus 2 initially performs a long-distance search so as to permit fast movement of the pick-up head 200 to the vicinity of the target data sector. Thereafter, the apparatus 2 performs a short-distance search to find the target data sector. It is noted that the pick-up head 200 may not be properly positioned relative to the target data sector at the start of the short-distance search, and is usually disposed at a nearby data sector within the vicinity of the target data sector. In the present invention, finding of the target data sector proceeds only after the accuracy of identification information of the nearby data sector has been verified.

Facts

Application

10/022,156Filed 14 Dec 2001

Published

US 2003/0112715 A119 Jun 2003

Granted

9 Sep 2003

Term ended

16 Jan 2022

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 33 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification6 codes

G11B 27/105
Programmed access in sequence to addressed parts of tracks of operating record carriers: of operating discs
G11B 20/1833
Error detection or correction; Testing , e.g. of drop-outs: by adding special lists or symbols to the coded information
G11B 27/3027
On the same track as the main recording: used signal is digitally coded
G11B 2220/2545
Optical discs: cds

Timeline

14 Dec 2001Application filedUS 10/022,156
19 Jun 2003PublishedUS 2003/0112715 A1
30 Jun 2003Assigned to Acer Laboratories, Inc.assignment of assignor's interest
9 Sep 2003GrantedUS 6,618,331 B2
1 Oct 2003Assigned to Ali Corporationchange of name
13 Sep 2005Assigned to Mediatek Inc.assignment of assignor's interest
16 Jan 2022Term endedEstimated, includes 33 days of adjustment

Method and apparatus for accessing target data in a data storage medium

Life of this patent

Method and apparatus for accessing target data in a data storage medium

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims8

Description3,238 words

Drawings

Classification6 codes

Life of this patent

Description3,238 words