Error detection/correction and fault detection/recovery – Pulse or data error handling – Digital data error correction
Reexamination Certificate
2000-01-25
2003-12-09
Ton, David (Department: 2133)
Error detection/correction and fault detection/recovery
Pulse or data error handling
Digital data error correction
C714S755000
Reexamination Certificate
active
06662335
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates in general to an apparatus and an operation method of a DVD. More particularly, this invention relates to an apparatus and a method to access DVD data.
2. Description of the Related Art
In recent years, the CD-ROM storage system has been speedily developed in both application and techniques. In terms of operation speed, from the early model of single speed, the current model has been developed with more than fifty times of the single speed. The capacity has also been increased from 650 Mega-byte to 4 Giga-Byte. Nowadays, the DVD plays a more and more important role. Currently, the DVD-ROM has approached a quad-speed. According to the development of CD-ROM, a DVD-ROM with a much higher speed is foreseeable. In addition to the operation speed, the performance of a DVD-ROM includes the capability of data accessing. That is, when the disk contains scratches or other defects, the DVD-ROM can still access the data of the disk precisely.
A brief description for accessing data of a DVD is introduced as follows.
In a DVD, an original data of 2048 bytes are stored in a data sector.
FIG. 1
displays the format for storing data in each of the data sector. From
FIG. 1
, each data sector comprises twelve rows of data. ID
102
having a length of 4 bytes is a number sequentially increasing according to the order of the data sectors. The identification error detection code (IEDC)
104
having a length of 2 bytes is used as data protection of ID
102
. The copyright management information (CPR_MAI)
106
with a length of 6 bytes is used to store the data related to copyright. The main data with a total length of 2048 bytes is shown in
FIG. 1
as well. After the scramble operation of ID
102
, the main data are stored in the main data segment
108
to
130
in sequence.
In addition to store data of 160 bytes in the main data segment
108
, and to store data of 168 bytes in the main data segment
116
, each of the rest of the main data segments from
110
to
128
stores data of 172 bytes. A sum of these data stored in the main data segments
108
to
130
is 2048 bytes (D
0
-D
2047
).
In the last row of
FIG. 1
, that is, the row comprises the data segment
130
, there is an error detection code (EDC)
132
with a length of 4 bytes. This error detection code
118
is obtained according to the data of 2060 bytes stored in the ID
102
, the IDEC
104
, the CPR_MAI
106
and the main data segments
108
to
130
. Therefore, the total length of a data sector is 2064 bytes.
To protect the data stored in a data sector, in a DVD, 16 data sectors, that is, 192 rows of data are treated as a unit encoded into an ECC block according to Reed Solomon Product Code (RSPC). As shown in
FIG. 2A
, data of 192 rows times 172 bytes, that is, data b
0,0
to b
191,171
are assembled according to the sequence of the data in the data sector. Referring to
FIG. 2B
, each of the 172 data columns is encoded by RS(
208
,
192
,
17
) according to RSPC, so that an outer-code parity (PO) data with a length of 16 bytes is added to each column as the 16 column of PO data b
192, 0
to b
207, 171
.
After generating the PO data, the whole sector of data is shown as FIG.
2
C. The whole sector comprises
208
rows of data, and each row of data is encoded by RS(
182
,
172
,
11
) to add inner-code parity (PI) data with a length 10 bytes in each column that is, the data b
0, 172
to b
0, 181
to the data b
207, 172
to b
207, 181
. The added PI data comprises data of 208 rows times 10 bytes. The ECC block is thus assembled.
FIG. 2D
shows the data storage configuration in a DVD disk. As shown in the figure, in the end of each data sector, a segment of PO data is added, while the PI data are added right after each row of the data sector. For example, after each of the twelve rows of the 0
th
data sector
210
, a 10 byte PI data is added. After the
0
th
data sector
210
and before the first data sector
220
, a PO
0
data
215
is added. It is similar to the first sector
220
, the second sector
230
until the 15
th
sector
240
. A PO
1
data
225
, a PO
2
data
235
, . . . , and a PO
15
data
245
are respectively added between the data sectors
220
,
230
, . . . and,
240
.
FIG. 3A
shows a structure for accessing data of a DVD, and
FIG. 3B
shows a flow chart for accessing data of the DVD. In
FIG. 3A
, an analog signal read from the disk
310
by the reading head
311
is converted into a digital EFM data
313
by an analog signal processor
312
. Being demodulated by the EFMPLUS demodulator
314
, the EFM data
313
becomes the row data
315
in a unit of bytes. According to the ID of the row data
315
, the row data interface
316
stores the required sector data to the memory
321
under the control of the memory controller
320
. While the data stored into the memory
321
by the row data interface
316
can be assembled as an ECC block, the RSPC decoder
317
accesses the data stored in the memory
321
via the memory controller
320
to decode of PI data and PO data, so as to correct the error data.
Each time when the RSPC decoder
317
finishes decoding PI data and PO data in an ECC block, the error detection code processor
318
accesses the data stored in the memory
321
via the memory controller
321
. The error detection code in each sector of the 16 data sectors in the ECC block is calculated. If all the error detection codes are correct, the host interface
319
descrambles and send the main data to the host
322
. If any of the
16
error detection codes is incorrect, there are two ways to process. One is to repeat decoding the PI and PO data by the RSPC decoder
317
once, followed by re-calculating the new error detection codes by the EDC processor
318
until all the error detection codes are correct. The other way is to access the ECC block by re-read the disk
310
by the reading head
311
. Through the same flow, the error detection codes are re-calculated until all the error detection codes are correct.
According to the above description, the accessing times for memory
321
can be obtained from the flow chart of FIG.
3
B. In step S
330
, after performing the EFMPLUS demodulation, the required sequential steps comprise: writing data into the memory
321
by the row data interface
316
in step S
331
; decoding PI data and PO data using RSPC decoder
317
and performing correction in steps S
332
and S
333
; calculating the error detection codes in step S
334
; and sending the data to the host
322
in step S
335
. Thus, the steps to access the memory
321
comprise writing the memory
321
in step
331
; reading the memory
321
in steps S
332
, S
333
, S
334
and S
335
; and correcting the memory in steps S
332
and S
333
.
Therefore, a calculation for the flow of the data can be presented as:
Each time when reading in an ECC block, a total amount of (192+16)×(172+10)=38038 bytes is to be written into the memory (as shown in FIG.
2
C).
In step S
332
, while decoding the PI data, an amount of (192+16)×(172+10)=38038 bytes are to be read.
In step S
333
, while decoding the PO data, an amount of (192+16)×172=35776 bytes are to be read.
In step S
334
, while calculating the error detection codes, 16 data sectors are to be read. Each data sector is of 2064 bytes, so that the total amount is 16×2064=33024 bytes.
When sending the data to the host
322
in step S
335
, the required amount of the data is 16×2048=32768 bytes.
In step S
332
and S
333
, as the accessed memory for correction of the PI data and PO data is negligible, therefore, the amount is not calculated.
According to the above calculation, when the host obtains the data of 16×2048 (that is, 32768) bytes, at least 177624 bytes of the memory are accessed. By the definition of DVD specifications a single speed for data transferring of a DVD is 1.385 Mbytes/sec. That is, for a single speed, the data accessing amount for the memory is 1.385×177624/32768=7.
J.C. Patents
Mediatek Inc.
Ton David
Torres Joseph D.
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