ISO/IEC TR 10091:1995
(Main)Information technology — Technical aspects of 130 mm optical disk cartridge write-once recording format
Information technology — Technical aspects of 130 mm optical disk cartridge write-once recording format
Is a complement to ISO/IEC 9171-2 for the type A and B formats. Covers the figures that characterize each format, the relationship between these figures, and the technological background used to reach decisions concerning the formats; in addition, gives some examples of implementation.
Technologies de l'information — Aspects techniques relatifs au format d'enregistrement pour les cartouches de disque optique de diamètre 130 mm, non réinscriptible
General Information
Standards Content (Sample)
TECHNICAL
lSO/IEC
REPORT TR 10091
First edition
1995-02-01
Information technology - Technical
aspects of 130 mm optical disk cartridge
write-once recording format
Technologies de I’informa tion - Aspects techniques relatifs au format
d’enregistrement pour /es car-touches de disque optique de diametre
130 mm, non rkinscriptible
Reference number
lSO/IEC TR 10091 :I 995(E)
---------------------- Page: 1 ----------------------
ISO/IECTRlO091:1995(E)
Page
Contents
1
Section 1 - General
1
1 Scope
1
2 References
1
3 Recording area and control track
2
4 Physical control track format
2
4.1 General aspects
2
4.2 Phase Encoded Part (PEP)
5
4.3 Standard Formatted Part (SFP)
6
Section 2 - Type A format
6
5 ccs
6
6 Track Format
6
7 Sector Format
9
7.1 Sector Mark
10
7.2 VFO Areas
13
7.3 Address Mark
13
7.4 ID field
1s
7.5 Offset Detection Flag (ODF)
1s
7.6 Gap
16
7.7 Flag
16
7.8 ALPC
17
7.9 Sync
18
7.10 Data field
21
7.11 Resync
22
7.12 Buffer
22
7.13 Delete pattern (Optional)
23
8 Error detection and correction
24
9 Modulation method
0 ISO/IEC 1995
no part of this publication may be
All rights reserved. Unless otherwise specified,
reproduced or utilized in any form or by any means, electronic or mechanical, including
photocopying and microfilm, without permission in writing from the publisher.
ISODEC Copyright Office l Case postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
---------------------- Page: 2 ----------------------
ISOIIEC TR 10091:1995(E)
o ISO/IEC
26
Section 3 - Type B format
26
10 Sampled Servo
26
11 Prerecorded signal properties
26
11.1 Schematic diagram of the disk mastering system
27
11.2 Signal amplitude of the prerecorded signal
30
11.3 Tracking error signal
32
11.4 Wobble marks
33
11.5 Clock mark
36
12 Sector header
36
12.1 Sector header format
36
12.2 Functionality of each part in the sector header
37
12.3 Reliability of the header information
39
13 Error detection and correction
39
13.1 Error correction capability
42
13.2 Estimated chip size of the LSI for EDAC
42
13.3 Correction time
42
14 4115 Modulation and differential detection
42
14.1 Modulation coding
4s
14.2 Differential detection
so
14.3 Implementation
Annexes
57
A- Reliability with 3 Ids (for Type A format)
60
B - Comments on error distribution (for Type A format)
63
C- Read write operation table (for Type A format)
65
D - Comments on read characteristics (for Type A format)
. . .
111
---------------------- Page: 3 ----------------------
ISO/IEC TR 10091:1995(E) 0 ISO/IEC
Foreword
IS0 (the International Organization for Standardization) and IEC (the International
Electrotechnical Commission) form the specialized system for worldwide standardiz-
ation. National bodies that are members of IS0 or IEC participate in the development
of International Standards through technical committees established by the respective
organization to deal with particular fields of technical activity. IS0 and IEC technical
committees collaborate in fields of mutual interest. Other international organizations,
governmental and non-governmental, in liaison with IS0 and IEC, also take part in the
work.
In the field of information technology, IS0 and IEC have established a joint technical
committee, ISOLIEC JTC 1.
The main task of technical committees is to prepare International Standards, but in
exceptional circumstances a technical committee may propose the publication of a
Technical Report of one of the following types:
- type 1, when the required support cannot be obtained for the publication of an
International Standard, despite repeated efforts;
- type 2, when the subject is still under technical development or where for any
other reason there is the future but not immediate possibility of an agreement on
an International Standard;
- type 3, when a technical committee has collected data of a different kind from that
which is normally published as an International Standard (“state of the art”, for
example).
Technical Reports of types 1 and 2 are subject to review within three years of
publication, to decide whether they can be transformed into International Standards.
Technical Reports of type 3 do not necessarily have to be reviewed until the data they
provide are considered to be no longer valid or useful.
ISO/IEC TR 10091, which is a Technical Report of type 3, was prepared by Joint
Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 23,
Optical disk cartridges for inform&ion interchange.
iv
---------------------- Page: 4 ----------------------
TECHNICAL REPORT o ISO/IEC ISO/IEC TR 10091:1995(E)
Information technology - Technical aspects of 130 mm optical disk
cartridge write-once recording format
Section 1 - General
1
Scope
This Technical Report is a complement to ISO/IEC 917 l-2 for the Type A and B formats.
This Technical Report covers the figures that characterize each format,
the relationship between these figures, and the
technological background used to reach decisions concerning the formats; in addition it gives some examples of
implementation.
2 References
ISO/IEC 9171-1:1990, Information technology -130mm optical disk cartridge, write once, for information interchange -
Part 1: Unrecorded optical disk cartridge
ISO/IEC 9171-2: 1990, Information technology -130mm optical disk cartridge, write once, for information interchange -
Part 2: Recording format
3 Recording area and control track
The recording area and control tracks are divided as given in table 1. The dimensions are for reference only, they are nominal
positions (see ISO/IEC 9171-2 clause 4).
Table 1 - Formatted Zone
-Reflective Zone 27,00 mm to 29,00 mm
-Control Track PEP Zone 29,00 mm to 29,50 mm
-Transition Zone for SFP 29,50 mm to 29,52 mm
-Inner Control Track SFP Zone 29,52 mm to 29,70 mm
-Inner Manufacturer Zone 29,70 mm to 30,OO mm
-Guard Band
29,70 mm to 29,80 mm
-Manufacturer Test Zone
29,80 mm to 29,90 mm
-Guard Band 29,90 mm to 30,OO mm
-User Zone 30,OO mm to 60,OO mm
-Outer Manufacture Zone 60,OO mm to 60,15 mm
-Outer Control Track SFP Zone 60,15 mm to 60,50 mm (maximum)
-Lead-Out Zone 60,50 mm to 61,OO mm
The inner radius of the Formatted Zone shall be at least 27,0 mm to avoid interference with the Clamping Zone.
The format of the Reflective Zone is not specified but it shall have the same reflective recording layer as the rest of the
Recording Zone. Servo information (grooves or pits) is not required in the Reflective Zone.
1
---------------------- Page: 5 ----------------------
o ISO/IEC
ISO/IEC TR 10091:1995(E)
The width of the PEP Zone is determined by the requirements for the accuracy of the drive head positioning system. The width
of 0,5 mm for the PEP Zone is sufficient for stable operation of the drive actuator mechanism. Since grooves are not required
in the PEP Zone, the track pitch may be changed to make it easier to read out the PEP without using a tracking servo.
A Transition Zone for SFP is provided to enable the optical head to move from the PEP Zone to the SFP Zone, which requires
a period for changing the translation mode of the optical head at the transition point from the PEP Zone to the SFP Zone in the
mastering process. The Transition Zone for the SFP Zone can be an unrecorded area.
Considering the accuracy of control of the media mastering equipment, the starting position of the outer SFP is to be
determined relative to the starting position of the inner control track and the tolerance built-up over the mastered area.
Within the Manufacturer Test Zone, it is recommended to have the same header format as that of the User Zone.
There shall be no pre-recorded information on tracks between 60,50 mm and 61 ,OO mm.
4 Physical control track format
There are two recording methods for the control track information to be placed into three different areas (PEP Zone, Inner and
Outer SFP Zones). The first method shall be used for the PEP (Phase Encoded Part) and the second method for the SFP
(Standard Format Part).
The PEP is recorded at the innermost radius and is recorded independently of the format (A or B) chosen for the rest of the
disk. This common PEP recording method allows a drive that is set up for either format A or format B to read the PEP
information. The PEP is intended to be read without requiring that servo tracking be established by the drive.
The SFP Zones must be recorded in the same format as the rest of the disk, (either format A or format B). It contains
additional information plus a duplication of the information in the PEP, so there is no requirement that the PEP be read by
every drive.
41 . General aspects
The control track areas provide information about the media that may be used to optimize the read and write characteristics of
the drive.
The innermost recorded zone, PEP, is recorded using low frequency phase encoded modulation, which can be read
independently of the characteristics of the servo method of the drive.
To facilitate drive compatibility with various media types, there is a hierarchy of information supplied, beginning with the
cartridge. The cartridge identifier sensor holes supply information to read the PEP. The PEP supplies enough information to
read the SFP, and the SFP supplies information to optimize write and read operations on user data. A drive can then be
adjusted by using each source of information in turn leading to the ability to read and/or write user data with optimal
efficiency.
The number of sectors per track in the SFP area equals the number of sectors per track at track No. 0. The outer SFP area
begins at track No. N+96 where N is the track number of the last track of the User Zone, and continues until radius 60,5 mm.
42 . Phase Encoded Part (PEP)
The maximum power applied to the media to read the PEP Zone of the Control Track shall not exceed 0,50 mW.
The low density of the PEP allows a high tolerance for media defects and permits decoding the information with a
microprocessor instead of a dedicated circuit. The loss of cross-track signal is limited in the PEP area in order to allow off-
track reading. Three methods to reduce the loss of cross-track signal are given in figure 1.
Taking into consideration the various methods, the loss of cross-track signal is defined as the maximum amplitude of the read
signal from channel one from three successive marks on the media, divided by the minimum amplitude of the read signal from
one revolution of the media (ignoring any effects from defective areas on the media).
This cross track ratio shall not exceed 2,0.
2
---------------------- Page: 6 ----------------------
o ISO/IEC ISO/IEC TR 10091:1995(E)
C
A
0
0
0
0
0
radial track
t
legend:
A : small track pit pattern
B : wide pit pattern
C : wobble pit pattern
Figure 1 - Example of pit recording in PEP
The recording sequence throughout the International Standard shall be MSB (most significant bit) first and from byte 0 to byte
n.
The PEP Control Track information in bytes 0 to 9 and byte 18 is mandatory for optical disks in order to conform to the
International Standard.
The bit assignment of the PEP is summarized in table 2. In order to show correct bit assignment, the following example is
given:
In 405 modulation bit 2 in byte 0 must be a ONE.
The definition of the lowest value for the amplitude of Pre-formatted data in byte 4 is as follows;
The lowest value in the type A format will be obtained by the recorded data pattern (33). The lowest value in the type B
format is obtained by the pattern (CO). All signal levels should be measured at the Inner SFP Zone.
3
---------------------- Page: 7 ----------------------
o ISO/IEC
ISO/IEC TR 10091:1995(E)
Table 2 - PEP summary
PEP Sector Data field summary
l3yte
re-formatted data
15 NOT SPECIFIED (Ignored in interchange)
r
(Ignored in interchange)
16 NOT SPECIFIED
1
(Ignored in interchange)
17 NOT SPECIFIED
18 CRC, (Covers bytes O-17)
---------------------- Page: 8 ----------------------
o ISO/IEC
ISOIIEC TR 10091:1995(E)
Standard Formatted Part (SFP)
43 e
The type of mark used for the SFP is a phase pit, and the recording format is identical with that of the Users Data area. Only
the first 5 12 bytes in a sector are used for recording the SFP data. If a 1024 byte sector is used, the remaining 5 12 bytes are
recorded as (FF). All unused bytes in the SFP shall be recorded as (FF).
---------------------- Page: 9 ----------------------
o ISO/IEC
ISO/IEC TR 10091:1995(E)
Section 2 : Type A format
5 ccs
The continuous servo tracking format, also called the Continuous Composite Servo, (CCS) tracking format, is explained in
this section. The Type A format is based on a CCS tracking method (see ISOIIEC 917 1-2 clause 5).
6 Track Format
In the push-pull tracking and signal detection scheme, d.c. and low frequency component offsets caused by disk skew and non-
concentric tracking must be compensated for, including worst case end-of-life conditions. To resolve these problems, a low
frequency tracking offset correction scheme may be used. This correction scheme is not always necessary, but it is required in
case of large amounts of tilt, as may happen at the end-of-life of media.
7
Sector Format
The Sector Format consists of the following fields:
(1) Sector Mark
(2) VFOl, VF02, VF03
(3) Address Mark
(4) ID field
(5) Postamble
(6) Offset detection flag
(7) Gap
(8) Flag
(9) ALPC area
(10) Sync
(11) Data field
(12) Resync
(13) Buffer
A sector for 1 024 user bytes consists of 52 bytes for the preformatted header area, 14 bytes for flag, gap, ALPC and ODF
field, 1274 bytes for the data and other fields and 20 bytes for the buffer.
protect the
The Resync field is not a discrete field, but instead, a series of special byte patterns inserted into the Data Field to
data from loss due to defects and subseq uent loss of by ‘te framin g by the read channe 1.
Each ID field has a Variable Frequency Ocilator (VFO) pattern, an Address Mark (AM) pattern and Identifier (ID)
information. The sector layout is shown in table 3.
By applying three redundant ID fields, reliable ID detection can be achieved when defects are present. Experimental data used
to validate the use of three ID fields is included in the annexes (especially see annex A).
6
---------------------- Page: 10 ----------------------
5B
14 BYTES
3B
3B 5B 2B
18
GAP
FLAG GAP ALPC
SECT. NO
\
CONTROL +
ECWCRC
RESYNC
AM
II
5 12598 20B
12B
128 1 5
4
52 BYTES 1274 BYTES
I
PRE-FORMATTED AREA -’
1360 BYTE SECTOR
CONTINUOUS SERVO
1 K SECTOR FORMAT
---------------------- Page: 11 ----------------------
ISWIEC TR 10091:1995(E) o ISO/IEC
A
B
NOTE
A: 2 ID fields of 4 byte of Sync/AM
B: 3 ID fields of 1 byte of AM
Figure 2 - Comparison of robustness between two different header formats
8
---------------------- Page: 12 ----------------------
o ISO/IEC ISOIIEC TR 10091:1995(E)
71 . Sector Nlark
Functions
The purpose of the Sector Mark (SM) is to reliably provide a timing window to begin synchronization of the read channel. It is
distinguished from address data or user data by its unique channel bit pattern and can be detected without recourse to a PLL.
Characteristics of the Pattern
The pattern does not exist in data and can be detected by a simple timing comparison. The detection of the redundant 3 and 5
channel bit time long pits is reasonably robust to the effects of short burst defects.
Example of a Detecting Circuit
Figure 3 shows an example of an SM detecting circuit, and figure 4 shows its action. The signal from the media passes an
amplifier and is converted to a pulse width signal by a binarization circuit. A serial-to-parallel conversion circuit along with a
time comparison outputs each pulse value at a fixed level. These parallel output signals are compared by majority logic.
As can be seen in figure 4, at most one signal pattern at a time is detected as ONE at time 0. Therefore, identifying the
patterns to equal an SM requires more than two ONES. An SM can be detected even if two output signals are missed. Since the
minimum detection criteria is 3 out of 5 pulses, it is highly unlikely that a combination of defects would occur to give a false
detection, and it is also unlikely a defect would destroy 3 out of the 5 patterns to cause a missed detection
Signal
Result of
from
SM Detection
Disk
Majority
Amplifier Binarization Parallelization
Logic Circuit
Circuit Circuit
Figure 3 - SM detecting circuit
9
---------------------- Page: 13 ----------------------
ISO/IEC TR 10091:1995(E) o ISO/IEC
5T 3T 3T 7T 3T 3T 3T 3T 5T
Time
Sequence
Output of Parallelization
circuit
Result of SM Detection
t=o
Figure 4 - SM detecting action
72 b VFO Areas
Functions
VFO fields are not equal in length or pattern (figure 5) for several reasons. VFOl has the functions to both stabilize the AGC
(automatic gain control) and to stabilize the PLL (phase-locked loop) on the clock of the signal from the disk.
VF02 stabilizes the PLL. As the AGC is assumed to have been stabilized already, the length of VF02 is shorter than that of
VFOl.
VF03 stabilizes the AGC for the written data field and also stabilizes the PLL. For AGC stabilization it is assumed that a
Channel bit stream from 0 to 80 Channel bits in length is necessary depending upon the circuit or method used.
Characteristics of the pattern
It is the most dense Channel bit pattern which is suitable to perform the above mentioned functions. The field size when
entering the VFO area from a region of unknown or unpredictable signal is 192 Channel bits, while that for the VFO preceding
ID1 and ID2 is 136 Channel bits. Since there is no gap proceeding the second and third ID fields, it is assumed that enough
information remains in the preceding field to establish the AGC level of the PLL. This leaves 136 Channel bit times for the
PLL to establish phase-frequency lock on the data stream.
Two VFO patterns prior to ID1 and ID2 are needed in order to allow the last byte of CRC to achieve closure. The patterns are
“100100100.010010” and “000100100.010010”.
Notice that the VFO fields always end in the same Channel bit pattern just before the Address Mark. The choice of initial
pattern for VF02 depends on the content of the last byte of CRC in the preceding ID field. The use of these patterns avoids the
necessity of having a gap between the end of an ID field and the beginning of the next VFO field.
10
---------------------- Page: 14 ----------------------
ISO/IEC TR 10091:1995(E)
o ISO/IEC
Detecting Circuit
Typical AGC and PLL circuits can be used. No attempt is made here to define such circuits, as ample information already
exists. However, it is recommended to add a circuit similar to that in figure 6 to make the PLL more stable. Its purpose is to
detect the frequency difference between the master clock and the read clock. When the difference reaches a specified criterion
(3% to 4%), it reestablishes the read clock using the master clock, then resumes reading. Thus, if the PLL looses frequency
synchronization due to a large burst error, reliable PLL operation can still be expected again after the defective area has
passed.
Comment on the length of the VFO
Pull-in times for phase-locked loop (PLL) circuitry used in production model of optical disk drives have been measured as
follows;
Company A : about 4,5 ps (48 Channel bits),
Company B : about 9 ps (96 Channel bits) in the worst case.
Therefore the length of the VFO region should not be less than 96 Channel bits. A VFO region of 136 Channel bits should be
long enough for pull-in of the PLL. An experimental circuit was used for measuring the pull-in time similar to that shown in
figure 6. The circuit was modified from what would be used in a production drive by reducing the allowed time for acquisition
by 50%. This means that this PLL is less stable than the production version. The signals shown in figure 7 show that the pull-
in response was sufficiently stable. The upper trace shows the switching signal which moves between 10,5 MHz and 10 MHz.
The figure shows that the pull-in for the VFO was completed within 3 psec (32 Channel bits).
This demonstrates that it is possible to design a PLL circuit whose pull-in time is shorter than 136 Channel bits and is still
stable.
11
---------------------- Page: 15 ----------------------
ISOLIEC TR 10091:1995(E) o ISO/IEC
pre-formatted area
VFOI , 2
VF02
8 8
VF03
12
NOTE - There are data on readability of ID’s in the following case (ID) (see annex A)
VFO I ID0 I ID1 ; ID2 : ID3
. . . .
b
Figure 5 - VFO fields
disk read signal
Ic Phase
-
Comparate
10.5 MHz
.
. 4
I
.
l
b LPF l - VFO L
7
*
1
clock
10 MHz
Figure 6 - Block diagram
12
---------------------- Page: 16 ----------------------
o ISO/IEC
ISOiIEC TR 10091:1995(E)
10.5 MHz to IO MHz IO MHz to 10.5 MHz
control voltage
0.5 Vldiv
2.0 psec/div
switching signal
Figure 7 - Observed pull-in response of PLL
73 . Address Mark
Functions
The purpose of the Address Mark (AM) is to detect the head of each ID field.
Characteristics of the Pattern
With the redundancy provided by three ID fields, it was not necessary to continue with another Sync Mark in front of each ID
field as once proposed. The Address Mark is a special pattern,
not found in RLL (2,7) data, and is a run length violation for
RLL (2,7) encoding.
Example of Detection Circuit
An example of a detection scheme is shown in figure 8. Both AM and SM detection may use similar circuits.
74 .
ID field
Functions
The purpose of the ID field is to identify the track number and the sector number.
The ID field consists of 4 sub-parts; a track number, an ID number (to identify the field as ID-l, ID-2 or ID-3), a sector
number, and a CRC. A successful ID field detection is when all of the 4 sub-parts and the preceding AM (6 bytes total) are
detected correctly in one read pass.
Characteristics of the Pattern
Reliable reading of ID information and bit and byte timing are achieved by the 3 IDS. Since the AM has an irregular pattern
which does not exist in any other area, the ID can be detected using it independently even if the SM fails to be detected.
Accurate bit timing in the sector can be set by using the ID number and CRC OK signal (explained later). This is especially
helpful if the SM happens to be missed due to an unusual burst error.
Example of Detection Circuit
Figure 8 shows an example of an ID detecting circuit, and figure 9 shows its timing. The sector-timing counter starts when an
SM is detected and the count indicates the Channel bit position within the sector. The AM detector detects the AM by pattern
matching, using the signal from the disk in a shift register.
The CRC circuit starts when an AM is detected and gets as input the track number, the ID number, the sector number, and the
CRC bytes read from the disk. It generates a CRC OK signal if the data plus the CRC bytes result in a zero residual.
The timing counter is readjusted by using both the CRC OK signal and the ID number. If the SM has not been detected, the
sector timing counter can start by using the CRC OK signal and the ID number.
13
---------------------- Page: 17 ----------------------
ISO/IEC TR 10091:1995(E)
o ISO/IEC
At the detection of an SM the PLL has not yet locked and the detecting window is rather large. There may exist an error of 1
or 2 Channel bits, but the correct Channel bit timing can usually be obtained by the first CRC OK signal.
The ID information is recorded 3 times and read data recovery is possible if at least one of the 3 ID’s is detected. This means
the format can stand a burst error of 320 Channel bits in length. A disk which has manufacturing defects over 100 pm (192
Channel bits) can be easily detected and eliminated before shipping. For write operations, it is recommended that at least 2 ID
fields be detected properly. This should give sufficient margin for aging.
Residual Polynomial of CRC
The CRC calculation is done with the registers initially preset to all ONES. Refer to ISO/IEC 917 1 for the generating
polynomial.
SM DETECT
Blt CLOCK b Sector Timing Counter
READ DATA
w AM Detector
CRC START ID No.
Decoder
t
I t 1
CRC Circuit
t--’ ’
I
CRC OK I
TR No., SC No.
-
.
to other circuit
* ID Register
Figure 8 - ID detecting circuit
\ I
READ DATA
ID2 1
SM AM ID0 AM ID1 -AM
*
1
SM DETECT
AM DETECT
.
. .
f
CRC on
*
CRC OK *2 3
(1st ID) (2nd ID) (3rd ID )
*l Sector Timing Counter starts
*2 Readjust the Sector Timing Counter
“3 If an error is detected then CRC OK is suppressed
Figure 9 - ID detecting timing chart
14
---------------------- Page: 18 ----------------------
ISO/IEC TR 10091:1995(E)
o ISO/IEC
75 . Offset Detection Flag (ODF)
ODF Marks (also known as Mirror Marks, or Mirror Flags) are areas of the media with no grooves or recorded information
for the length of 16 Channel bits.
Some of the basic principles of track offset signal detection are shown in figure 10. ODF marks are independent of the
recording method and may be selectively used for offset correction according to the amount of disk skew, and the tracking
accuracy required.
In some cases, offset correction would be applied only to tracking for data recovery. In other cases, offset detection would be
used only for the detection of the allowable offset signal for write operation, thus providing protection from writing in the
wrong area. These ODF marks will not have any adverse effects on the continuous tracking signals even if they are not used
for offset correction. The short duration of the marks make their presence completely compatible with the classic CCS
Moreover, no additional area is required for the ODF area. The use of the marks is left to the drive
pregroove format.
designer’s choice.
MIRROR
LIGHT SPOT
FLAG
\
,.I., ,L-ml, *‘,,pvwPq.,~- ,-A*. ‘“my;:.1 “-,.*,‘:: ‘.y%y-pyr,r:yy, *cl,--. :“y - ‘u’yn*.-aq$j-, ,r* c”’ wc*eq ,p’ :”
AREA y:‘:
. . .: ,,IJL , ,).I. ,rL” . . ” ,1&.
.‘I,“__ I: ,‘,;,i,‘. I, ,4’ ‘: ,,,1:‘/;, ,. 6 .I’ ,,?
*.
,., ,;.,;,:,, I.’ ’ y,,p II 11. ‘., ., - c I’ , ’ .“.I ‘, r,“s *
‘,,, I. .ci I;,
:,;‘.! . II, :. I, ,) I+. , ,1’ y.
.‘I .,. :,‘,i’i :‘*.
/’ :;<‘,,yy ~., (1” $8 ‘L.,n I
(,,” ,,‘: .;., a,,!,.
‘b!j I,,‘, , . ’ ,, ; 1 I. ,j,“’ /”
8;;; ,* ,‘?I (( .;:I l/N1’/, ‘,,,/- ,,_, ::. ‘*: ’ “,‘,‘,dP ,.,, -/,I,
L.’ 1
.’ I , - , i IJ!,,.” ,’ .I
., ~,‘,,,~~~:b;,*:U,~‘“.“.P”,‘. &I.”
.i!L,! ,,,;L, &4;Virii&&.” uu Al, L4rl,. z:,lull;*. I&.~.*. .d .h,i: CL-: ,,iP ‘1 ,.,,‘r, : :; J I,x+*.,. l,*,t.h. a ,,,,. edi* I
,F’ ‘-I+‘, 2.” ‘yy,“p.” ;I, *I - ‘;‘:y”’ *‘:~“A~;~ lyvrr ,h, , ,.:~;::V,‘*nrz~,l’~r*~. v--s -- ‘yr”,y yeTy,reVT ‘y ‘,‘/ ,4*c, c-7: qy qyv.
my.’ ., /*. /./
1,; ‘, .: ‘f I*“;. ,.,:I, ,, ,,, ,! : ,‘v. ‘I : ‘L.
$y :‘j) j’ ’ I y!; ‘$ ‘:f q;;‘i:‘:“,;,, : y,i “$,‘) :‘:”
:* ‘,‘! ,‘1 11,
.., . ‘.:b:,:“,, ~,yb.:‘~,
‘,:, ;,I:, ::d~,:;;:;;j:,; .g, ‘,: ‘, *. +:: I 4.
/1 ‘&Q.{G,.,, ,,:pw$$f’,, I, . $ i,‘),,:
‘. .‘,: ’ , :
,$i.A I’
‘Lp’ , 11, 4: :,,j ,, 1.: ,;.:,; ,x ‘!:.I? ,: “‘!l”l’i;;,r~;“~~,~~.,‘,,.,~“.l 1,
#,,&t:,,,” ;;: ‘1; ” :*Lf”,, &;:.
>,!I’ ,I
!~, ,,&+: ,,Vdr,& ‘. ‘1. t 5, 4: :a
: :&,$&#: !n’&J!L , 11, ,, ,,,;; .:;;f;‘;,i;,.,
t/l,, I b-u. ?. I., D 41,. .hmtL.* r ‘&. .‘: ! *!u&L-r. a.,‘, *. “.:,t~‘h.
OFFSET +
SIGNAL
(A) Light Spot on Track Axis
+
I
(B) Light Spot off Track Axis to Left
YI iWlj:lj?$T P: '~,l"i~*II;!;~~~~"~~~:,'~ ' '.' .*I 1." *'.,"F: y-r , "ywl,f?FI,'y yyprivpiw r-?“‘? * ’ .4nny;: * “,‘;,,“? f!,W” I”(,‘% ‘,J .i:t”yJ44~y’: !,yy ;~~wpy;,“: ’
v$$y ;‘jq;“l~py$fy $yy?y$ IT’*: wy~~-w T’“! _
y ;., ,‘. :: ‘. ,
2;:' ,,,, ,p, , '0 , ,,,+:,* ,*'~,,:.;:I I?,’ ,q~,af,,‘G4-,. :.a _.,,l),s ,,.,, :,/a
, ,,,. ( ,, p&,";; ~~~~~e: 81~s *:I ,‘,!I;,,; ,$:,I;; ~1,~s x*,.$,t’It * ,t, I %“k,‘::Ad ll’s’t*b,,, r: ~, ; I , ,,* Y:, . . ,’ ‘,- “’ ,,.‘;I. I
,,Q?' "/,,I '8, Ir ,,1,, 4’ iv’. 11.1, I ai 1.’ ,
' :'I '::;G;:;:; <:,, ;;,;?$ ?,,. v;;i ,G,, $ 61, -1’ . 4,. ;:,,:1*,,::,p , II,‘:,:: , , ,“:1 ‘y$ ,.,< I;. ,.I ,,a !, II;;: ,
,,,;,& fit ,, y;, ::';r:~~~::ii~~.~~~ 11, -;, : T
* ,,'," ,‘. .*,“~~‘;‘“‘,.“.“;
+r; q4. ,,,(, ,,hJI- 'U :I 14. 1" ":Qp*;' ,I : ; ,;, ';:'; . I;,, ,.; I
*, j,,, ,I: :,; ;;&;; r;,j$,$; -,;:/II ’ : ” j ,:‘: a. , :& : . r:~y-+l’~~ ~;r;;~~!J!~,, ,:, 1;;; , ;,;t&j
.*,,*',l., ,,,e [',, ,:.>ia;F ,sfl; I* 1 I/ ,.‘:,,I::“:.‘: :‘:l,,I!:,” ,,.
I 1 1411!l :,.:' I,,Lj~&~~[& /,,,
/~~~;y,rl;,,,,,l',"~,.", .* ,. , , i~\'+WVl 1'1 L:I' q . " I',',' I',,' ', ,'$,I: ill
,"Y ,,, ,Qd ,&. $,j&&& :ld: I;%‘:::‘&.! &;: ‘L&. ~,.4,:)$- k A. :,: :
A", Irw4u1 .,z4"," .d%h'i ., * Lr. .tiwr. d'v?I,l:: . . ht., : A1 /. * :, 8Jm?b;;. 1.2 ': :, ~ . . .rrll.,,~wr,,.a.,,,,l~~‘I 1*,,‘,1 al’::‘,??.: “I ‘!:::;.:L , L :Jii9l\.l’.,
/
(C) Light Spot off Track Axis to Right
Figure 10 - Generation of track offset signal
76 .
Gap
A gap consists of an un-written area of 48 Channel bits on either side of the FLAG field to absorb the time fluctuation of flag
writing.
15
---------------------- Page: 19 ----------------------
o ISO/IEC
ISO/IEC TR 10091:1995(E)
77 . Flag
Functions
A flag allows a micro processor to make a fast decision as to the status of the sector, without having to read the entire sector
and to attempt an ECC correction. The flag is written after the data area write operation has been completed successfully. The
Flag field is required to be written in any media conforming to the International Standard.
Characteristics of the pattern
It is the shortest pattern with the most resistance to defects that allows the controller to distinguish wheth
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.