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Illllllllllllllllllllllllllllllllllllllllllllllllll 

© Publication number: 0 428 208 A2 



© EUROPEAN PATENT APPLICATION 

<£) Application number: 90202943.8 © Int. Cl.5 : G1 1 B 20/18, G1 1 B 7/00 



@ Date of filing: 07.11.90 



<§) Priority: 13.11.89 US 434794 


© 


Applicant: Laser Magnetic Storage 






International Company 


© Date of publication of application: 




4425 Arrows West Drive 


22.05.91 Bulletin 91/21 




Colorado Springs Colorado 80907(US) 


© Designated Contracting States: 


® 


Inventor: McFerrin, William Patrick 


DE ES FR GB IT NL 




c/o INT. OCTROOIBUREAU B.V., Prof. 






Holstlaan 6 






NL-5656 AA Eindhoven(NL) 






Inventor: Hines, Randal Curtis 






c/o INT. OCTROOIBUREAU B.V., Prof. 






Holstlaan 6 






NL-5656 AA Elndhoven(NL) 




© 


Representative: Groenendaal, Anton ius 






Wilhelmus Maria et ai 






Internationaal Octrooibureau B.V. Prof. 






Holstlaan 6 






NL-5656 AA EindhOven(NL) 



© Sector slip with address collision recovery for write once recording media. 



© A method and an apparatus for storing data on a 
high speed write-once recording media such that 
random writes and fast random accesses are possi- 
ble. Writes are verified by decoding reflections of 
write pulses from the recording media, and compar- 
ing the decoded data with intended data. The re- 
cording media is divided into a plurality of bands. 
When a write for a sector of a band is rejected 
during verification, sector slip occurs and an attempt 
is made to rewrite the data in a next sequential 
sector of the band. When more than a predeter- 
mined number of slips have occurred in a band or a 
data collision occurs, the data is written in a preal- 
iocated spares area of the recording media. 




Europaisches Patentamt 
European Patent Office 
Office europeen des brevets 



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SECTOR SLIP WITH ADDRESS COLLISION RECOVERY FOR WRITE ONCE RECORDING MEDIA. 



The present invention relates to an apparatus 
and a method for writing data onto recording me- 
dia, and more particularly, for writing data at high 
speeds onto a write-once recording media from 
which data will be read at high speeds. 

Over the last decade, there has been an ever- 
increasing demand for recording media having 
larger and larger amounts of storage capacity. One 
solution to this demand has been the so-called 
write-once recording media (WORM), such as op- 
tical discs. Data on an optical disc is stored in the 
form of a series of pits formed in the surface of the 
disc. WORMs are specially useful in applications 
where the data base is extremely large but rela- 
tively static, such as the Library of Congress book 
cataloging data or the U.S. Geological Survey's 
data of the topography of the United States, as 
WORMs can store in excess of two gigabytes of 
data on a single surface. 

In view of the amount of data being stored on 
such media, efficient media management is essen- 
tial. Media management systems for WORMs that 
have been introduced to data are relatively simple. 
The rotation rates of these WORMs during reading 
and writing is relatively slow, with the fastest of 
these WORMs being rotated at approximately eight 
revolutions per second (rps). Accordingly, devices 
that write data onto and read from such media 
function at relatively low data transfer rates and 
require media management techniques, need only 
be effective at these rates. However, computers are 
being introduced which process data at greater and 
greater rates. Persona! computers are now being 
developed that will process data at many times the 
one to two million instructions per second (MIPS) 
rates now available in top-of-the line personal com- 
puters, and it is expected that computers that pro- 
cess data at 100 MIPS may soon become com- 
mon. Storage media must be developed which can 
be read at sufficient speeds so as to satisfy the 
data transfer requirements of these faster comput- 
ers. 

When writing data onto WORMs, such as op- 
tical discs, at the relatively low speeds, it is ac- 
tually possible for the writing device to watch and 
read the pits being formed by a laser in the surface 
of the WORMs. This is known as direct read during 
write (DRDW). Accordingly, during a write opera- 
tion, a write controller can almost instantly deter- 
mine whether the data written was the same as the 
data intended to have been written. However, 
present writing devices cannot watch the pits being 
formed at the reading and writing speeds required 
for the new faster computers. This loss of a valu- 
able quality control tool is a major impedent of the 



development of higher speed WORMs. 

Random access to the WORMs during the 
write process is a desirable feature. Data can be 
written on WORMs at predetermined addresses of 
s the WORMs, which speeds up recall of data. Blank 
areas can be left to enable future updating of data. 
If the media management technique used for a 
WORM does not permit random access and 
changes to the database contained on the WORM 
10 are desired, the WORM must be replaced or sup- 
plemented. Supplementing a WORM requires a 
secondary storage media and some combination of 
additional software, additional hardware, and ma- 
chine instructions to provide access for a user to 
15 the secondary storage media. These options are 
expensive and/or time consuming. Clearly, a media 
management technique which permits random ac- 
cess is desirable, as it would permit future updating 
and greater latitude when performing the initial 
20 write on a WORM. Thus, a need exists for a media 
management system which allows random access 
during a write operation to a high-speed WORM. 

Any media management system must also take 
into account defects encountered during writing. 
25 Media defects may economically be determined 
only as the media is being written. Defects can be 
caused by gouges or other defects in the media 
surface itself, by dust which has accumulated on 
the media surface or which otherwise interferes 
30 with the laser beam during the write, or by vibra- 
tions during the write. Typically, less than 0.3 per- 
cent of addressable areas of a media surface will 
be declared defective. However, given the total 
number of addressable areas on a typical WORM, 
35 the number of defective areas will be large and 
poses a problem that must be addressed. 

Efficiency is another important criteria for me- 
dia management. The media management system 
must be designed so that an optimum average 
40 transfer rate performance is achieved, and a mini- 
mum spin up time is required for the WORM. In 
accessing data, the actual physical address is thou- 
sands of addresses away from its logical address 
as perceived by the host, an adequate system 
45 must be in place so that the data can be accessed 
quickly and efficiently. Otherwise, relatively large 
quantities of time are used to find the physical 
address. Additionally, given the demands for stor- 
age space outlined above, media utilization should 
so be as efficient as possible. 

One proposed method of media management 
is directed to dealing with media defects. When a 
defect is found in a first addressable area on the 
surface of the media during a write operation, a 
"slip" to a next addressable area of the media is 



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performed. That is, when a defect is found in a first 
addressable area of the media, such as a surface 
defect or an incorrect write, the controller attempts 
to write the date meant for the first addressable 
area in the next addressable area. This system of 
media management has the highest media utiliza- 
tion efficiency, since the only media cost is for 
replacements. However, such a system is effective 
when a sequential write is being performed, and 
would be difficult to implement when random ac- 
cess to all sectors is desired. Given that the sur- 
face of a media may contain over two million 
physical addresses, and given the typical defect 
rate of 0.3 percent, the "physical" address of data 
being written can be thousands of addresses away 
from its "logical" address (the address to which the 
data was directed). Such differences would se- 
verely effect the data recovery efficiency in a ran- 
dom access system, as finding the required data 
would take an inordinate amount of time. However, 
after a read is started, the read access efficiency 
for one area in the portion to be read is very high, 
as the data will be found in the next sequential area 
of the WORM if the first area is defective (if the 
next area is not defective). 

Another media management technique current- 
ly in use for the relatively slow WORMs preal- 
locates portions of a WORM for replacement of 
defective areas. The replacement portions may be 
distributed over the WORM so as to provide fast 
access. When a defect is detected, a predeter- 
mined method is imposed by which the replace- 
ment portions of the WORM are utilized. Since the 
allocation of replacements can have no specific 
relationship to the distribution of defects, then 
some written relocation table must be utilized so 
that this variation can be tracked for reading. The 
maintenance of this table carries some impact on 
the media utilization efficiency. The area available 
for this maintenance should be chosen to match 
the maximal number of anticipated defects. The 
physical reference to each preallocated replace- 
ment is divided into two disjoint sets: the defect 
replacement set and the relocation table space. 

Such a media management technique provides 
contiguous logical address space and random ac- 
cess to all sectors. However, media utilization can- 
not be 100%, since even if the area reserved for 
defects is equal to the area containing defects on a 
particular WORM, additional space is required on 
the WORM for mapping these replacements. Fur- 
ther, replacement access efficiency is low, as the 
defective (intended) area must be read, then the 
mapping area corresponding the defective area 
which indicates the location of the replacement 
area must be read, and finally the replacement 
area itself must be read. As these areas are not 
likely to be contiguous, several rotations of the 



WORM are likely to be necessary. 

To date, no media management technique for 
high speed WORMs has been introduced which 
permits random access during both reading and 

5 writing, has high replacement access efficiency, 
and high media utilization efficiency. 

Accordingly, it is an object of the present in- 
vention to provide a method which permits random 
access of a recording media during writing. 

10 It is a further object of the present invention to 

provide media management technique for high 
speed recording media which provides both high 
replacement access efficiency and high media utili- 
zation efficiency. 

75 Yet another object of the present invention is to 

provide a recording media which uses a media 
management technique which achieves optimum 
average transfer rate performance. 

Yet another object of the present invention is to 

20 provide a media management technique which pro- 
vides reduced spin-up time for a recording media. 

A further object of the present invention is to 
provide a media management technique for record- 
ing media which realizes host-initiated reallocation 

25 of space on the media. 

To achieve the foregoing objects and in accor- 
dance with the purpose of the invention, as em- 
bodied and broadly described herein, a method for 
writing data onto a recording media is provided 

30 which comprises the steps of: (1) determining 
whether a sector of the recording media to be 
written with data contains any previous write; (2) 
writing the data in a spares area and generating a 
map therefor when the sector contains any pre- 

35 vious write; (3) writing the data onto the sector and 
determining whether the sector contains an accept- 
able number of errors during the write when the 
sector contains no previous write; (4) repeating the 
method in a next sector for next data when the 

40 sector is determined to contain an acceptable num- 
ber of errors; and (5) slipping to a next sequential 
sector when the sector is determined not to contain 
an acceptable number of errors in the third step 
and repeating the method to attempt to write the 

45 data onto the next sequential sector. 

Preferably, the errors being counted include 
write errors and recording media defects. With 
respect to a further step, prior to the first step: (6) a 
first sector to be written is pre-qualified as blank 

so during a write transaction in which a plurality of 
data is to be written into respective sequential 
sectors. 

The first step may include the substeps of: 
determining whether the sector contains an indica- 
55 tion of a previous write; proceeding to the third 
step if no indication is found; reading the sector to 
determine if data has been written in the sector if 
the sector contains an indication of a previous 



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write; proceeding to the second step if data has 
been written in the sector; determining whether a 
logical overwrite is being attempted if the sector 
has not been written in; aborting the writing if it 
determined that a logical overwrite is being at- 
tempted; and proceeding to the third step if it is 
determined that a logical overwrite is not being 
attempted. 

Preferably, the recording media is divided into 
a predetermined number of bands, each of the 
bands having a predetermined number of sectors, 
and the method further comprises the step of: (7) 
quantifying the number of slips in the band to be 
written prior to the first step, wherein the fifth step 
further comprises proceeding to the second step of 
writing the data in the spares area when the num- 
ber of slips exceeds a predetermined number. The 
fifth step may further comprise counting the num- 
ber of consecutive slips and proceeding to the 
second step of writing data in the spares area 
when the number of consecutive slips equals a 
predetermined number. Alternatively, the fifth step 
may further comprise counting the number of con- 
secutive slips and aborting the write when the 
number of consecutive slips equals a predeter- 
mined number. 

The second step of writing the data in the 
spares area may comprise the substeps of: (1) 
obtaining an address of a next available sector in 
the spares area; (2) writing the data in the next 
available sector in the spares area and determining 
whether the next available sector contains an ac- 
ceptable number of errors; (3) when the next avail- 
able sector does not contain an acceptable number 
of errors, repeating the second substep for the data 
in a next sequential sector in the spares area; and 
(4) when the next available sector contains an 
acceptable number of errors, repeating the second 
substep for next data, if any, in the next sequential 
sector in the spares area. 

The method may further comprise the step of, 
prior to the third step: (8) writing an overwrite 
protection indicator into a portion of the sector for a 
first sector to be written in a writing transaction. 
Additionally, the method may further comprise the 
step of, when no data has been written in the 
spares area: (9) postqualifying a predetermined 
number of consecutive sectors following a last sec- 
tor written during a write transaction. 

An apparatus for carrying out the method com- 
prises: a device for determining whether a sector of 
the recording media to be written contains pre- 
viously written data; a device for writing data on the 
sector of the recording media and detecting de- 
fects in the sector and the data being written; and a 
device for moving the recording media relative to 
the writing and detecting device so that the writing 
and detecting device attempts to write the data into 



a next sector when the sector is detected as being 
defective, and attempts to write the data in a 
spares area of the recording media when the deter- 
mining device determines that the sector contains 

a previously written data. 

The apparatus may further comprise a device 
for generating a map entry and writing the map 
entry onto a predetermined sector of the recording 
media when the determining device determines 

w that the sector of the recording media to be written 
onto contains previously written data and the mov- 
ing device moves the recording media relative to 
the writing and detecting device so as to write the 
data in the spares area. 

15 The recording media can be divided into a 

predetermined number of bands, each of the bands 
containing a predetermined number of sectors. Fur- 
ther, the apparatus may further comprise means for 
counting the number of times the moving device 

20 has moved the recording media relative to the 
writing and detecting device for attempting to write 
the data into a next sector in a given band, and 
causing the moving device to move the recording 
media relative to the writing and detecting means 

25 so that the writing and detecting device attempts to 
write the data in the spares area when the count 
exceeds a predetermined number. 

Other objects and advantages of the present 
invention will be set forth in part in the description 

30 and drawings which follow, in which like reference 
numbers represent like parts throughout, and, in 
part, will be obvious from the description, or may 
be learned by practice of the invention. 

Fig. 1 is a schematic view of a recording media 

35 and reading/writing apparatus according to the 
present invention; 

Fig. 2A is a diagram of media certification dur- 
ing write for an unflawed area of the recording 
media; 

40 Fig. 2B is a diagram of media certification dur- 
ing write for a flawed area of the recording 
media; 

Fig. 3 schematically illustrates a first division of 
the surface of the recording media according to 
45 the present invention; 

Fig. 4 illustrates a second division of the surface 
of the recording media according to the present 
invention; 

Fig. 5 illustrates a third division of the surface of 
50 the recording media according to the present 
invention; 

Fig. 6 is a diagram illustrating the formatting of a 
72-segment portion of the recording media; 
Fig. 7 is a diagram illustrating the form in which 
55 data is stored in a sector of the recording me- 
dia; 

Fig. 8 is a diagram of the format of a controller 
record for a host area sector; 



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Fig. 9 is a diagram of the format of a controller 
record for a spares area sector used for collision 
recovery; 

Fig. 10 is a diagram of the format of a controller 
record for a spares area sector used for re- 
location; 

Fig. 11 is a diagram showing the format of a 

controller record for a map sector; 

Figures 12A-12B are flow charts of the primary 

processing steps of the present invention; 

Fig. 1 3 is a flow chart illustrating the steps to be 

followed when media defects and/or an improper 

write require a sector slip; and 

Fig. 14 is a flow chart illustrating the processing 

steps to be followed when a sector of data is to 

be written in a spares area. 
Reference will now be made in detail to the 
present preferred embodiment of the invention, ex- 
amples of which are illustrated in the accompany- 
ing drawings. 

Fig. 1 is a schematic drawing of a system for 
writing on a recording media with which the 
present invention can be carried out using the 
appropriate software. A write-once recording media 
(WORM) 10 for storing data, such as an optical 
disc, is rotatable by a motor 12. In high speed 
applications, the motor 12 will rotate the recording 
media 10 at relatively high speeds, such as 162/3 
revolutions per second (rps). A write controller 20 
controls a read/write assembly 14 for writing data 
onto and reading data from the recording media 
10. The read/write assembly 14 is movable relative 
to the center of the recording media 10 by a 
servomechanism (not shown). The motor 12 and 
the servomechanism operate in tandem to position 
the read/write assembly 14 over the required por- 
tion of the recording media 10 in cooperation with 
the write controller 2u by methods known in the art. 

The read/write assembly 14 includes a laser 16 
for generating a laser beam. The laser 16 performs 
several functions and operates at two different in- 
tensities. Typically, when the write-once recording 
media 10 is an optical disc, data is recorded on the 
WORM 10 as a series of pits. The pits are formed 
in the WORM 10 by a write pulse from the laser 
16, which is a laser pulse having a relatively high 
first intensity. When the laser 16 operates at a 
relatively low second intensity, pits will not form in 
the surface of the recording media 10, as the 
intensity of the laser beam at the second intensity 
is not strong enough to form pits. Rather, the 
second intensity is used for reading data from the 
WORM 10. The reflection of a laser beam from a 
pit in the recording media 10 has different char- 
acteristics than the reflection of a laser beam from 
a regular surface of the recording media 10. Optics 
18 of the read/write assembly 14 detect the re- 
flected laser light, which is decoded in data de- 



coder 22. The decoded data is then forwarded for 
use as required by the computer (not shown). 

At high rotation speeds, conventional media 
management techniques, such as direct read dur- 
5 ing write (DRDW) are not effective. As discussed 
above, due to the high channel rates (data through- 
out speeds) it is not presently feasible for the 
reading mechanism to directly observe each for- 
ming pit as the intensity of the laser beam drops 
70 from the write puise to the reading intensity. By 
reading the data from a WORM as it was being 
written and comparing the read data with the data 
intended to have been written, a simple and highly 
accurate writing system was possible. The present 
75 invention proposes to replace DRDW as follows. 

In order to assure a high accuracy writing 
system, a high speed data verification technique 
had to be provided. A technique known as data 
verification during write (DVDW), which is de- 
20 scribed in greater detail in copending U.S. Patent 
Application Serial No. 07/428,106, filed October 27, 
1989, entitled "Apparatus And Method For Verifica- 
tion Of Data Established On A Record Carrier Dur- 
ing Write" and assigned to the same assignee, is 
25 one such technique. While at the newly required 
speeds it is not possible to read the pits as they 
are being formed, it is possible to monitor the 
intensity of the laser beam being produced by the 
laser. To form a pit having desired characteristics 
30 in the surface of the recording media 10, a laser 
beam having a certain intensity is required over a 
known period of time. Accordingly, by monitoring 
the laser intensity, it is possible to detect the data 
the laser is writing. It follows that a write can be 
35 verified with a high degree of certainty by compar- 
ing data obtained while monitoring laser intensity to 
data intended to have been written. Accordingly, 
the optics 18 in the read/write assembly 14 also 
monitors each write pulse generated by the laser 
40 16. Assuming that a write pulse of sufficient 
strength forms a pit, the optics 1 8 detect whether a 
pulse of sufficient strength to form a pit is reflected 
from the surface of the recording media 10 during 
a write. By monitoring the laser intensity, the optics 
45 18 detects each byte of data, which it has sensed 
should have been written on the surface of the 
recording media 10, and transmits this sensed data 
to the write controller 20 via the data decoder 22. 
The write controller 22 stores data representative of 
so the data intended to have been written, which was 
previously sent to the read/write assembly 14 via a 
data encoder 26. The write controller 20 then car- 
ries out a byte-by-byte comparison of the detected 
byte and the intended byte. If a match is not found, 
55 an error signal will be generated. 

Another technique used by the present inven- 
tion takes advantage of the fact that the laser 1 6 is 
kept on at all times during the write operation in 



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order to prolong the life of the laser 16. The write 
controller 20 and the data encoder/laser control 
circuit 28 control the intensity of the laser 16 based 
on data to be recorded in the recording media 10. 
When a pit is to be formed in the recording media 
lu, the write controller 20 and the data encoder 28 
cause the laser 16 to produce a high intensity write 
pulse, which is directed at a desired location on the 
surface of the recording media 1 0 in order to burn 
a pit into the recording media 10 at the desired 
location. When the laser 16 has been maintained at 
the high intensity long enough to burn a pit having 
the proper configuration in the surface of the re- 
cording media 10, the data encoder/laser control 
circuit 28 ends the write pulse, and the laser 16 
returns to producing the read or low intensity sec- 
ond beam. The read intensity is maintained when- 
ever the laser 16 is not producing the high intensity 
beam. 

The present invention utilizes the above char- 
acteristic to perform media certification during write 
(MCDW) for uncovering defects in the recording 
media 10, which is described in greater detail in 
copending U.S. Patent Application Serial No. 
07/428,167, filed October 27, 1989, entitled 
"Apparatus And Method For Certification Of A 
Record Carrier During Write" and assigned to the 
same assignee. When the laser 16 is not being 
used to write, the optics 18 of the read/write as- 
sembly 14 monitor the surface of the recording 
media 10 for defects between write pulses. That is 
in every given area of the recording media 10, the 
optics 18 receive the reflection of the low intensity 
laser beam off of the recording media 10 between 
positions at which the laser is forming pits in the 
area. This received data is sent to the write 
controller/native device interface 20. If the surface 
of the recording media 10 between intended pit 
positions is blank and not otherwise disfigured, the 
reflections received by the optics 18 from these 
non-pit positions should have known normal char- 
acteristics. When the reflections from all of such 
position in the given area of the recording media 
10 have these normal characteristics, that area of 
the recording media 10 is considered certified. An 
area which is certified is illustrated in Fig. 2A. Fig. 
2A illustrates an area of the surface of the record- 
ing media 10 which consists of 15 positions. Of 
these 15 positions, it is intended that pits be 
formed at positions 2, 5, 9 and e. During the write 
in this area, high intensity write pulses from the 
laser 16 are used to form pits at positions 2, 5, 9 
and e. The reflection from the low intensity beam is 
read for the positions in the area between the 
intended pit positions. Since the pattern is blank at 
these positions (no pits and/or surface disfigura- 
tions), this area of the media is certified, and no 
MCDW signal is generated indicative of a defective 



area. 

In contrast, Fig. 2B illustrates an area in which 
an identical write is carried out, but during the write 
defects of some type are detected at positions 7 

5 and 8. Accordingly, the MCDW indicator goes high 
for these positions, and an MCDW signal indicative 
of a defect in that area of the surface of the 
recording media 10 is generated. 

The media management scheme of the present 

io invention will now be described beginning with a 
reference to Figures 3-14. 

In order to obtain the most efficient storage 
system, the recording media 10 is divided into a 
plurality of individually addressable regions, each 

15 region being subdivided at least twice more. Each 
addressable region and subdivision thereof con- 
sists of a contiguous continuous portion of the 
recording media 10. 

Bands are the highest order of these regions. 

20 Each band is individually addressable, and consists 
of a continuous surface portion of the recording 
media 10. As illustrated in Fig. 3, the recording 
media 10 is divided into a plurality of bands lb, 2b, 
(n)b, for a total of n bands. As illustrated in Fig. 

25 4, each band b is separated into a plurality of 
sectors Is, 2s, (x)s. A total of x sectors constitute 
each band. The lowest order division of the record- 
ing media 10 is the servo segment. As illustrated in 
Fig. 5, each sector s is divided into a plurality of 

30 servo segments Iss, 2ss, .... (y)ss, for a total of y 
servo segments (segments). 

The combination of the band number, sector 
number, and segment number designates a spe- 
cific portion of the surface of the recording media 

35 10. For illustrative purposes, it will be assumed that 
the surface of the recording media 10 is divided 
into 128 bands, each band being divided into 
16,448 sectors, each sector containing 72 seg- 
ments. In each segment, 18 bytes of data (16 

40 recordable bytes and 2 servo bytes) can be re- 
corded. 

As discussed above, both the "slip" technique 
and the preallocation technique of media manage- 
ment have certain advantages and disadvantages. 

45 Generally, these are the opposite for each tech- 
nique. The present inventors have found a way to 
combine these two techniques, so as to obtain a 
media management technique which provides ran- 
dom access to the WORM during both reading and 

so writing, high replacement access efficiency, and 
high media utilization efficiency. In doing so, the 
inventors had to overcome the very real possibility 
of data collisions that could result when random 
writes and slipping are both permitted. This tech- 

55 nique is discussed below. 

The sector is the smallest addressable portion 
of the media surface. Since 0.3% of the sectors on 
the surface of the recording media can be ex- 



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pected to be defective, a portion of the surface of 
the recording media 10 is dedicated for defective 
sectors and reallocations. Given that each band is 
divided into 16,448 sectors, and that 0.3% of the 
sectors for any given band are expected to be 
defective, in a band having typical defects, the 
average maximum slip between logical and phys- 
ical addresses in the band is 49 sectors. The last 
64 sectors in each band are reserved for realign- 
ment of any such slip in order to prevent the slip 
from propagating across the media surface and to 
maximize media utilization. If the sectors in the 
reserved realignment area do not exhaust the slip, 
data intended to be recorded in sectors within the 
band is forwarded to reserve sectors in a preal- 
located spares area of the recording media 10. 

The layout of a typical sector is illustrated in 
Fig. 6. The first segment of the sectors segment 0, 
is reserved for control purposes, in segment 0, 
bytes 0-6 are preformatted to indicate the sector 
address. Bytes 7-9 are left blank to allow drive 
electronics sufficient time to verify the sector ad- 
dress. Bytes 10-11 of segment 0 are reserved for a 
block write start flag. At the beginning of any write 
transaction, a block write start flag is written into 
these bytes of the first sector to be written. Before 
writing into each sector, these bytes of the respec- 
tive segment 0 are checked for the existence of the 
block write start flag, as will be explained later. 
Bytes 12 and 13 are reserved to give the drive 
electronics time to verify the block write start flag, 
while bytes 14 and 15 are reserved. Bytes 16 and 
17 hold servo data. The recordable fields for each 
sector are found in segments 1 through 71. Bytes 
16 and 17 of segments 1-71 are reserved for servo 
data, leaving bytes 0-15 (1136 total bytes) for re- 
cording data. 

The 1136 bytes of data to be recorded are 
protected by an interleaved Reed-Solomon code 
composed of five data code words, C1 , C2, C3, C4, 
C5, and one control code word, the controller 
record CR. Interleaving will normally be carried out 
in the write controller/native device interface 20. 
Data code words C1, C5 are physically inter- 
leaved across the 71 segments, and the controller 
record CR is physically interleaved with the five 
data code words. Interleaving of the code words 
and the controller record is performed by known 
interleaving techniques. The breakdown of the data 
contained in the five code words C1, C2, C3, C4, 
C5 and the controller record CR is illustrated in Fig. 
7. Each code word contains 222 bytes, including 
206 data bytes and 16 parity bytes, except for the 
code word C5, which contains 200 data bytes, 16 
parity bytes, one byte for compatibility with other 
disc devices, one byte reserved for future use, and 
four bytes which protect the code words C1, C2, 
C3, C4, C5. The controller record CR includes a 



total of 26 bytes, including 14 recordable control 
bytes and 12 parity bytes. Thus, a single sector 
can store 1,024 bytes of data from the database to 
be stored. 

5 The controller record CR takes on one of four 

different formats, depending on the location of the 
sector. Fig. 8 illustrates the controller record CR for 
a sector located in the data recording (host) area of 
a band of the recording media 10. Of particular 

10 importance are bytes 5-10. Bytes 5-7 contain the 
actual physical address of the sector in the record- 
ing media. Bytes 8-10 of a sector always contain 
the physical sector address of the sector of data 
(the logical sector) which was intended to have 

15 been written at that address. When sector slip has 
occurred somewhere earlier in the band, that is, 
when due to a defect in the surface of the record- 
ing media 10, the write controller will write a sector 
of data in a physical address different from the 

20 logical address to which it was intended. Thus in 
this situation, the logical address in bytes 8-10 will 
be different than the present physical address of 
the sector in bytes 5-7. Bytes 11-13 contain a 
physical address in the spares area where a next 

25 sector to be written will be written in case of an 
address collision or a host-initiated reallocation, 
both of which will be explained later. The next 
spares address is initially discovered when the 
recording media 10 is initialized at spin-up, and is 

30 updated dynamically as address collisions and 
reallocations occur. This provides high replacement 
access efficiency. 

Fig. 9 is a chart of a controller record CR for 
spares area sectors used for collision recovery. In 

35 this type of controller record, bytes 0 and 1 specify 
that the sector is in the spares area, and is used 
for address collision recovery, i.e. a sector is writ- 
ten here when a write is attempted in the host area 
which collides with an already written sector. Bytes 

40 5-10 serve the same purpose as bytes 5-10 in the 
controller record for host area sectors. Bytes 11-13 
store the next available address for a map entry. A 
map area is also reserved in the recording media 
10 for storing map entries. Maps are generated 

45 when an address collision occurs. The next map 
address available is discovered during spin-up 
when the recording media 10 is initialized. 

Fig. 10 is a chart of a controller record CR for 
spares area sectors used for relocation. In this 

so controller record, bytes 5-13 serve the same func- 
tion as bytes 5-13 in the controller record for 
spares area sectors used for collision recovery 
illustrated in Fig. 9. In this controller record, bytes 
2-4 contain the last physical address, if available, 

55 of the previous address of the logical sector before 
this location. 

Fig. 11 illustrates a controller record CR for 
map sectors. Bytes 0 and 1 identify the controller 



7 



13 



EP 0 428 208 A2 



14 



record as a map sector controller record, while 
bytes 2-4 identify the logical address of the sector 
in the map area. Logical map sector 0 is located at 
the highest address in a controller management 
area. Logical map sectors increase with decreasing 
physical sector addresses. Bytes 8-10 contain the 
physical address of the last full map group, if any. 
Byte 11 contains the number of map entries in this 
sector. The overall number of map indexes equals 
171 minus the number of map entries. Bytes 12 
and 13 store the number of map entries currently 
in the current map group. Each map group is 
limited to 7,309 entries. Map entries and map in- 
dexes are contained in code words of this sector. 
Each map entry contains the logical sector address 
and its physical sector address, while each map 
index contains a three byte field referring to the 
map index, which is a logical sector address, and 
another three byte field which refers to the physical 
sector address for the map sector. 

The normal operation of a write procedure ac- 
cording to the present invention is described below 
with reference to the flow charts of Figures 12A 
through 12B. In a system which permits random 
access to the surface of the recording media, a 
write procedure begins with a write transaction 
being requested. Each write transaction is a re- 
quest to write a certain number of sectors at pre- 
determined, normally sequential, physical address- 
es on the recording media 10. In step 100, the 
write controller determines whether a map of the 
requested sectors is already in existence. If so, the 
map is checked to see if the requested sectors 
have been allocated (step 101). If it is determined 
that the sectors have already been allocated, the 
write controller will attempt to write the data in a 
spares area, as will be described later. If no map 
exists of the requested sectors, or, if a map does 
exist but it is determined that the sectors are not 
allocated (step 101), the operation proceeds to step 
102, in which the accumulated slip in the band in 
which the requested sectors are located is quanti- 
fied. In step 1 03, it is determined whether the first 
sector requested by the write transaction is blank. 
If the sector is not blank, the operation follows the 
same procedure as when the mapped sectors are 
found to be allocated in step 101. This procedure 
will be discussed later. If the first sector is blank, 
the status of a predetermined number (i) of follow- 
ing sectors is determined in step 104. 

At this time, actual writing onto the surface of 
the recording media begins. In step 105, a block 
write start flag is written in the appropriate bytes of 
the first sector to be written during this write trans- 
action. This prevents this sector from being over- 
written in the future by slippage from sectors hav- 
ing lower addresses, etc. The write controller then 
causes the data for the first sector to be written in 



the first sector, uses the media certification during 
write (MCDW) technique described above to detect 
defects in each code word for this sector, and 
monitors the reflection from the surface of the 

5 media during the write to determine whether the 
correct data was written. In step 106, the write 
controller determines whether the write was good 
or not. Usually, this is performed by comparing the 
total number of defects found by MCDW in each 

to code word in the sector plus the number of error 
signals generated indicative of incorrect data hav- 
ing been written with a threshold number of accept- 
able errors n. In the preferred embodiment, if more 
than two such errors occur for any code word in a 

75 sector, then the sector is rejected as faulty and a 
slip occurs, as will be described later. If the write is 
accepted, the operation then proceeds to step 107. 

In step 107, the write controller checks whether 
the transaction has been completed. If the transac- 

20 tion has been completed, the write controller post 
qualifies the next n sectors (step 108) and awaits 
the next write transaction request (step 109). The 
status of the next n sectors is checked on the 
same rotation of the recording media by the motor 

25 following the write in the last sector of the write 
transaction. Thus, the status of these sectors will 
already be known for future use, rendering 
prequalification unnecessary. If the transaction has 
not been completed, then the write controller pre- 

30 pares to write the next sector of data to be written. 
This next data is normally intended to be written in 
the next sequential sector (step 110). 

In preparation for writing the next data to be 
written, the next sequential sector is first checked 

35 for a block write start flag indicative of the begin- 
ning of a previously written transaction and a po- 
tential data overwrite (step 111). The write control- 
ler checks bytes 10 and 11 of segment 0 of the 
sector to be written, and uses the time provided by 

40 the blank bytes 12 and 13 of segment 0 the verify 
the contents of bytes 1 0 and 11 so as to not lose a 
rotation while checking on the existence of the flag. 
If evidence of a potential overwrite (the block write 
start flag) is found, then the write controller deter- 

45 mines whether there would actually be data colli- 
sion by reading the sector in question. This quali- 
fication of the sector costs one rotation of the 
recording media (step 112). Reading of the sector 
in question should determine whether or not data 

so has previously been written there. If data has been 
written in that sector, the data intended for that 
sector will be written in the spares area, in accor- 
dance with a procedure which will be discussed 
below. 

55 If it is determined in step 112 that no data has 

been written in the sector in question, the write 
controller attempts to determine if the host is at- 
tempting a logical overwrite (step 113). A logical 



8 



15 



EP 0 428 208 A2 



16 



overwrite has occurred when two sectors have the 
same logical address. If this is the case, the write 
transaction is aborted and the host is informed of 
the error (step 114). If it is determined in steps 112 
and 113 that there is no data collision and that the 
host is not attempting a logical overwrite, then it is 
likely that the overwrite (block write start flag) de- 
tected in step 111 was caused by a defect. In this 
case, and in the case where no overwrite is de- 
tected in step 111, the next data to be written is 
written in this sector. Simultaneously, the recording 
media in this sector is checked for defects by 
MCDW and the intensity of the laser reflection 
monitored for data verification (step 115). If no 
more than the threshold number of such errors 
exist in any code word written in the sector, then 
the media is considered acceptable and the data 
verified for the sector, and the write is treated as 
correct (step 116). The operation described in 
steps 107 through 116 is then repeated for the 
remainder of the write transaction. However, if it is 
determined in step 113 that the write was not 
successful, or if it is determined in step 113 that 
the write for any subsequent sector in the write 
transaction was not successful, then a sector slip 
will be performed, as described below. 

The flow chart of Fig. 13 illustrates the pro- 
cessing steps to be taken should a sector slip be 
required. In step 117 the accumulated slip in the 
band, as quantified in step 102, is checked to see 
if it is greater than the maximum expected number 
of slips m for the band, or, more precisely, the 
maximum expected number of slips less one (m- 
1), as the quantified accumulated slip has yet to 
have been incremented for this slip. As described 
above, the maximum expected number of slips 
across an entire band in the preferred embodiment 
is 49. If too many slips have occurred in the band, 
the data will be written in the spares area. This 
type of reallocation is discussed below. If the accu- 
mulated slip is less than the maximum expected 
number of slips, it is determined in step 118 wheth- 
er a predetermined number of consecutive slips 
have occurred. In the preferred embodiment only 
seven consecutive slips are allowed. After this 
many slips, there is most likely a problem in the 
recording media or the controlling hardware. In the 
preferred embodiment, for a host area sector, an 
attempt will be made to write the data in the spares 
area after seven slips, which will be described later. 
Alternatively, the write transaction can be imme- 
diately aborted after seven consecutive slips and 
an alarm given. 

Should the number of consecutive slips be less 
than the maximum number allowed, the next se- 
quential sector in the band is checked for overwrite 
protection in the form of a block write start flag 
(steps 119 and 120). The same protocol is used in 



steps 121 through 123 for checking an overwrite 
indication as was used above in steps 112 through 
114. Once again, should there be no data collision 
in the sector and if it is determined that the host is 

5 not attempting a logical overwrite, or it is deter- 
mined in step 120 that no overwrite indicator is 
present in the sector, the write controller writes the 
data that was intended for the previous sector in 
this new sector. Like the write described in step 

io 115, the media is concurrently checked for defects 
and the reflection of the laser beam monitored for 
data verification purposes (step 124). If it is found 
in step 125 that there are fewer than the predeter- 
mined threshold number of media and data errors 

75 in all code words of the sector, then the write is 
considered acceptable, and the operation returns to 
step 107 for the next sector to be written in the 
write transaction, if any (step 120). If there are 
more than the threshold number of errors in any 

20 code word another slip will be attempted. The 
accumulated slip count and the consecutive slip 
count are first incremented by one (step 1 26), and 
then steps 117-125 are repeated for the next slip 
attempt. 

25 As mentioned briefly above, should any one of 

a number of events occur during the normal opera- 
tion illustrated in Figs. 12A-12B or the sector slip 
operation illustrated in Fig. 13, an attempt is made 
to write the remaining data in a write transaction in 

30 the spares area of the recording media. These 
events include a determination in step 101 that the 
sectors for the write transaction have already been 
allocated, a determination in step 103 that the first 
sector for a write transaction is not blank, a deter- 

35 mination in step 112 or step 121 that a data colli- 
sion would occur in a sector to be written, a deter- 
mination in step 117 that, following a slip, the 
accumulated slip in the band is greater than a 
predetermined maximum expected number of slips, 

40 and a determination in step 118, following a slip, 
that more than a predetermined number of con- 
secutive slips have occurred. As discussed above, 
the address of the next available sector in the 
spares area is maintained in bytes 11-13 of control- 

45 ler records for host area sectors. As this data is 
initially discovered at spin-up and updated dynam- 
ically as address collisions and reallocations occur, 
when one of the above events happens, the ad- 
dress of the next available spares area is readily 

so accessible. 

The flow chart of Fig. 14 illustrates the pro- 
cessing steps for writing sectors of data in the 
spares area. In step 130, the write controller goes 
to the next available spares area address after the 

55 occurrence of one of the above events. In step 131, 
the data to have been written in the host area 
sector is written in the first available sector in the 
spares area, and just as with any other write, the 



9 



17 



EP 0 428 208 A2 



18 



media is monitored for defects and the reflection of 
the laser beam is monitored for data verification. 
Should it be determined that the number of media 
and data errors for any code word in the sector is 
greater than the acceptable number in step 132, 
then a slip is attempted in the spares area. Since 
the write is sequential in the spares area, no data 
collisions should be possible. Further, the total 
number of slips does not matter in the spares area. 
Accordingly, slipping is simpler in the spares area 
compared to the slipping performed in the host 
area (steps 117-126). However, the number of con- 
secutive slips is still monitored. Should the number 
of consecutive slips be found to have reached a 
predetermined number in step 133, then there is a 
likelihood that there is a problem with either the 
recording media or the writing equipment. The 
write transaction is then aborted and the host in- 
formed of the error (step 140). In contrast, should 
the number of consecutive slips be fewer than the 
threshold number, the data is written in the next 
sector while the media is certified and the data 
verified through monitoring of the reflection of the 
laser beam (steps 134-130). The operation then 
returns to step 132. 

When a Write is accepted in step 132, it is 
determined whether the transaction is complete 
(step 136). If it is not complete, the next data to be 
written from the write transaction is written in the 
next sector, and the sector is checked for media 
defects and the data is verified through monitoring 
of the reflection of the write pulses (steps 138 and 
139). The operation then returns to step 132, in 
which it is determined if another slip is necessary 
due to the written data and/or the media being 
judged to be unacceptable. If this is the case, a slip 
is performed in accordance with the above de- 
scribed procedures. If not, it is determined whether 
the write transaction has been completed (step 
136). When the write transaction is finally com- 
pleted, a map entry is generated and the next write 
transaction is awaited (step 1 37). 

While one embodiment of the present invention 
has been discussed, it would be appreciated by 
those skilled in the art that various modifications 
and variations are possible without departing from 
the spirit and scope of the invention. 



Claims 

1. A method for writing data onto a recording 
media, comprising the steps of: 

(a) determining whether a sector of the record- 
ing media to be written with data contains any 
previous write; 

(b) writing the data in a spares area and gen- 
erating a map therefore when the sector con- 



tains any previous write; 

(c) writing the data onto the sector and deter- 
mining whether the sector contains an accept- 
able number of errors during the write when the 

5 sector contains no previous write; 

(d) repeating said method in a next sector for 
next data when the sector is determined to 
contain an acceptable number of errors in said 
step (c); and 

70 (e) slipping to a next sequential sector when the 
sector is determined not to contain an accept- 
able number of errors in said step (c) and re- 
peating said method to attempt to write the data 
onto the next sequential sector. 
15 2. A method for writing data according to Claim 1 , 
wherein the errors include write errors and record- 
ing media defects. 

3. A method for writing data according to Claim 1, 
further comprising the step of: 

20 (f) prior to said step (a), pre-qualifying a first 
sector to be written in as blank during a write 
transaction in which a plurality of data is to be 
written into respective sequential sectors. 

4. A method for writing data according to Claim 1, 
25 wherein said step (a) comprises the substeps of: 

(1) determining whether the sector contains an 
indication of a previous write; 

(2) proceeding to said step (c) if no indication is 
found; 

30 (3) reading the sector to determine if data has 
been written in the sector if the sector contains 
an indication of a previous write; 
(4) proceeding to said step (b) if data has been 
written in the sector; 

35 (5) determining whether a logical overwrite is 
being attempted if the sector has not been writ- 
ten; 

(6) aborting the writing if it is determined that a 
logical overwrite is being attempted; and 
40 (7) proceeding to said step (c) if it is determined 
that a logical overwrite is not being attempted. 

5. A method for writing data onto a recording 
media according to Claim 1, wherein the recording 
media is divided into a predetermined number of 

45 bands, each of the bands having a predetermined 
number of sectors, said method further comprising 
the step of: 

(g) prior to said step (a), quantifying the number 
of slips in the band to be written in, wherein said 
50 step (e) further comprises proceeding to said 
• step (b) when the number of slips exceeds a 
predetermined number. 

6. A method for writing data onto a recording 
media according to Claim 5, wherein said step (e) 

55 further comprises counting the number of consecu- 
tive slips and proceeding to said step (b) when the 
number of consecutive slips equals a predeter- 
mined number. 



10 



19 



EP 0 428 208 A2 



20 



7. A method for writing data onto a recording 
media according to Claim 5, wherein said step (e) 
further comprises counting the number of consecu- 
tive slips and aborting the write when the number 
of consecutive slips equals a predetermined num- 
ber. 

8. A method according to Claim 1, wherein said 
step (b) comprises the substeps of: 

(1) obtaining an address of a next available 
sector in the spares area; 

(2) writing the data in the next available sector in 
the spares area and determining whether the 
next available sector contains an acceptable 
number of errors; 

(3) when the next available sector does not 
contain an acceptable number of errors, repeat- 
ing said substep (2) for the data in a next 
sequential sector in the spares area; and 

(4) when the next available sector contains an 
acceptable number of errors, repeating said 
substep (2) for next data, if any, in the next 
sequential sector in the spares area. 

9. A method according to Claim 1 , further compris- 
ing the step of: 

(h) prior to said step (c), writing an overwrite 
protection indicator into a portion of the sector 
for a first sector to be written during a writing 
transaction. 

10. A method according to Claim 1, further com- 
prising the step of: 

(i) when no data has been written in the spares 
area, post-qualifying a predetermined number of 
consecutive sectors following a last sector writ- 
ten during a write transaction. 

11. An apparatus for writing data onto a recording 
media, comprising: 

means for determining whether a sector of the 
recording media to be written on contains pre- 
viously written data; 

means for writing data on the sector of the record- 
ing media and detecting defects in the sector and 
the data being written; and 

means for moving the recording media relative to 
said writing and detecting means, so that said 
writing and detecting means attempts to write the 
data in a next sector when the sector or written 
data is detected to be defective, and attempts to 
write the data in a spares area of the recording 
media when said determining means determines 
that the sector contains previously written data. 

12. An apparatus for writing data onto a recording 
media according to Claim 1 1 , further comprising: 
means for generating a map entry and writing the 
map entry onto a predetermined area of the re- 
cording media when said determining means deter- 
mines that the sector of the recording media to be 
written onto contains previously written data and 
said moving means moves the recording media 



relative to said writing and detecting means so as 
to write the data in the spares area. 

13, An apparatus for writing data onto a recording 
media according to Claim 11, wherein the record- 

5 ing media is divided into a predetermined number 
of bands, each of the bands containing a predeter- 
mined number of sectors, said apparatus further 
comprising: 

means for counting the number of times said mov- 
io ing means has moved the recording media relative 
to said writing and detecting means due to a defect 
for a given band and causing said moving means 
to move the recording media relative to said writing 
and detecting means so that said writing and de- 
rs tecting means attempts to write the data in the 
spares area when the count exceeds a predeter- 
mined number. 

14. A media management method for controlling an 
attempt to write data onto a sector of a recording 

20 media, comprising the steps of: 

a) writing the data onto a preallocated reserve 
sector when the sector contains a previous 
write; 

b) writing the data onto the sector and monitor- 
25 ing sector errors during the write when the sec- 
tor contains no previous write; 

c) repeating said step (b) for the data in a next 
sequential sector when the sector errors are 
unacceptable; and 

30 d) repeating said method for next data in a 
following sequential sector from the completed 
write. 



35 



40 



45 



50 



55 



11 



EP 0 428 208 A2 




12 



EP 0 428 208 A2 



PATTERN: _ 0 _ _ 0 0 _ 0 

POSITION: 1 23456789abcdef 



WRITE SIGNAL: 



MCDW SAMPLING: m mm mmm mmmm m 



MCDW INDICATOR: 
MCDW SIGNAL: 



PATTERN: 


_ 0 


O.xxO 0 _ 


POSITION: 


1 2 


3456789abcdef 


WRITE SIGNAL: 




inn n_ 


MCDW SAMPLING: 


m 


mm mmm mmmm m 


MCDW INDICATOR: 
MCDW SIGNAL: 




. I I 


J 


L 



13 



EP 0 428 208 A2 



10 



1b 


2b 


3b 


4b 


5b 


6b 


} I 


(n-2)b 


(n-l)b 


(n)b| 



3*icj/. 3 



SECTOR 



D 

(I 



1s 


2s 


3s 


4s 


5s 


6s 


J / 


(x-2)s 


(x-Ds 


(x)s 




J 



Y 

BAND 

3*1^. 4 



SERVO 
SEGMENT 



a : 



s 

r 1 



1ss 


2ss 


3ss 


* / 


(y-2)ss 


(y-1)ss 


(y)ss 





y 

SECTOR 

3 Up. 5 



14 



EP 0 428 208 A2 



SEGMENT: 


BYTE: 


DATA: 


FUNCTION: 


0 


0 * 

1 * 

2 * 

3 * 

4 * 

5 * 

6 * 
7-9 

10-11 
12-13 
14-15 
16-17 


M1F 

00-Oxff 
00-Oxff 
00-Oxff 
Oxff-00 
Oxff-00 
Oxff-00 

0x4949 


SECTOR MARK 
SECTOR ADDRESS 
TRACK ADDRESS MSB 
TRACK ADDRESS LSB v 
! (TRACK ADDRESS LSB) 
! (TRACK ADDRESS MSB) 
! (SECTOR ADDRESS) 
GAP (HEADER VERIFICATION) 
BLOCK WRITE START FIELD 
GAP (BWS VERIFICATION) 
RESERVED 
SERVO BYTES 


1-71 


0-15 
16-17 


xxxx 


RECORDABLE FIELD 
SERVO BYTES 



CODEWORD: 


MESSAGE: 


ECC BYTES: 


CODEWORD: 


[d] 


206 


DATA BYTES 


16 


PARITY 


BYTES 


CODEWORD: 


[c2] 


206 


DATA BYTES 


16 


PARITY 


BYTES 


CODEWORD: 


[c3] , 


206 


DATA BYTES 


16 


PARITY 


BYTES 


CODEWORD: 


[c4] 


206 


DATA BYTES 


16 


PARITY 


BYTES 


CODEWORD: 


[c5] 


200 


DATA BYTES 










1 


BYTE LD1200 












1 


BYTE RESERVED 












4 


BYTES CRC 


16 


PARITY 


BYTES 


CODEWORD: 


[cr] 


14 


CONTROL BYTES 


12 


PARITY 


BYTES 



3*hCjj. 7 



15 



EP 0 428 208 A2 



BYTE: 


FIELD: 


DESCRIPTION: 


0-1 
2 

3-4 

5- 7 

6- 10 
11-13 


ess 

vol 
nrs 

Isa 
ipa 
nsa 


EXTENT STATUS CF SECTOR: 

3000= FIRST SECTOR OF WRITE 
0x4000= INTERMEDIATE SECTOR OF WRITE 
0x2000= LAST SECTOR OF WRITE 

LD1200 COMPATABILITY 

NUMBER OF SECTORS REMAINING FOR 
THIS WRITE TRANSACTION 

LOGICAL SECTOR ADDRESS 

INTENDED PHYSICAL ADDRESS 

NEXT SPARES ADDRESS AVAILABLE 




^u^. 8 


BYTE: 


FIELD: 


DESCRIPTION: 


0-1 
2-4 

5-7 

8-10 

11-13 


crt 
nrs 

Isa 
ipa 
nma 


CONTROLLER RECORD TYPE = 0x0100 
NUMBER OF SECTORS REMAING TO WRITE 

FOR THIS REQUEST 
LOGICAL SECTOR ADDRESS 
INTENDED PHYSICAL ADDRESS 
NEXT MAP ADDRESS AVAILABLE 




3u^. 9 


BYTE: 


FIELD: 


DESCRIPTION: 


0-1 

2-4 

5-7 
8-10 
11-13 


crt 
Ipa 

Isa 
ipa 
nma 


CONTROLLER RECORD TYPE = 0x0200 
LAST PHYSICAL ADDRESS OF RELOCATED, 

SECTOR, Oxffffff IF NONE 
LOGICAL SECTOR ADDRESS 
I INTENDED PHYSICAL ADDRESS 
NEXT MAP ADDRESS AVAILABLE 



3*Ui/. 1 0 



16 



EP 0 428 208 A2 



BYTE: 


FIELD: 


DESCRIPTION: 


0-1 
2-4 
5-7 
8-10 

11 

12-13 


crt 
Ima 
ipa 
lum 

nre 
nrg 


CONTROLLER RECORD TYPE = 0x0400 
LOGICAL ADDRESS IN MAP SPACE 
INTENDED PHYSICAL ADDRESS 
PHYSICAL ADDRESS OF LAST FULL MAP GROUP 
(Oxffffff IF THERE IS NONE) 
NUMBER OF MAP ENTRIES IN THIS SECTOR 
NUMBER OF MAP ENTRIES IN MAP GROUP 



17 



EP 0 428 208 A2 



WRITE TRANSACTION 
REQUESTED 



•101 



•100 



SECTORS 
ALLOCATED?. 



EXISTING 
"MAP OF REQUESTED^ 
SECTORS? 



N 


Tn 




QUANTIFY THE 
ACCUMULATED 
SUP IN BAND 










^fIrST SECTOR^OL,, 




DETERMINE 
STATUS OF 
NEXT i 
SECTORS 




* 


/ 


WRITE BWS FLAG 
IN FIRST SECTOR. 
WRITE FIRST DATA j 
IN FIRST SECTOR. 
CHECK FOR DEFECTS/ 
INCORRECT WRITE 



•102 



104 



105 



■106 



OF DEFECTS/ 
INCORRECT WRITE 
JN ANY CODE-. 
.WORD >n?> 



18 



EP 0 428 208 A2 




19 



EP 0 428 208 A2 




GO TO NEXT 
SECTOR 




20 



EP 0 428 208 A2 




GO TO NEXT 
AVAILABLE SECTOR 
IN SPARES AREA; 
GENERATE MAP 
ENTRY 



130 



■14-0 



C 



ABORT TRANSACTION 
INFORM HOST OF 
ERROR 

133 



I 



WRITE DATA IN 
FIRST AVAILABLE 
SECTOR: CHECK FOR 
SECTOR DEFECTS/ 
IN CORRECT WRITE 



#.OF 
'CONSECUTIVE' 
SLIPS IN SPARES 
AREA >7? 



132 

? OF- * 
DEFECTS/ 

Incorrect writes 
in any code- 
WORD >n£, 



•131 



134 



GO TO 
NEXT 
SECTOR 



135 



WRITE NEXT DATA 
IN NEXT SECTOR; 
CHECK FOR SECTOR 
DEFECTS/INCORRECT 
WRITE 



T 



138 



TRANS- 
ACTION 
COMPLETE' 




137 



END; AWAIT 
NEXT TRANSACTION 



139 



WRITE NEXT DATA 
IN NEXT SECTOR; 
CHECK FOR SECTOR 
DEFECTS/INCORRECT 

WRITE 



I 



21