Electrical computers and digital data processing systems: input/ – Input/output data processing – Peripheral adapting
Reexamination Certificate
2000-10-10
2002-07-16
Gaffin, Jeffrey (Department: 2182)
Electrical computers and digital data processing systems: input/
Input/output data processing
Peripheral adapting
C369S013010, C369S059160, C369S085000
Reexamination Certificate
active
06421750
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to prestage processes necessary in state of the art production of glass masters for compact disk replication.
2. Description of the Prior Art
Currently, the useful information made available to CD manufacturers for the purpose of replication is furnished on a plurality of greatly differing music/data carriers, each having highly specific features, depending on the existing infrastructure of the client placing the order and the nature of the information concerned. In this respect the type of music/data carrier selected decisively influences both the time and depth needed for processing in the CD plant. At this time the following music/data carriers are of significance throughout the branch:
Music/data
read/write
other important
carrier
speed
features
Analog tapes
real time
digital conv. necessary
low speed
high processing expense
9-track tapes
real time
low storage capacity
low speed
high processing expense
U-matic tapes
real time
low speed
prone to error
low storage capacity
medium to high
processing expense
DAT tapes
real time
medium storage capacity
low speed
medium processing expense
Exabyte tapes
approx. 2-3
high speed
times
rel. high date security
real time
high storage capacity
low to medium expense
CD-WO/MO disks
approx. 2
high speed
times
rel. high date security
real time
high storage capacity
low processing expense
premastering
Premastering
Depending on the nature on the music/data carrier furnished, its mechanical/physical quality as well as the structure of the useful information, various steps in processing prior to mastering, i.e. premastering are required of the CD manufacturer specific to the music or data carrier involved. These processing steps may involve e.g. inspection on receival for faults in the carrier (e.g. poor tape quality), adding supplementary information (subcode data, producing a disk description protocol (DDP)), and, where necessary, correcting the useful information stored or the structure thereof as ordered by the client. These checking and processing tasks are usually done on PCs or workstations to which the necessary input/output units specific to the carrier concerned are connected (see
FIG. 5
on page 41).
For implementing these checking and processing tasks, and depending on the music/data carrier or necessary depth of processing involved, it is often necessary to make a partial or even complete transfer of the information to the hard disk(s) of the checking or processing system. To ensure a zero-error, bit-accurate transfer of the useful information on the hard disk concerned an error protocol may be included in the write-in. In addition the reading speed of the input units can be reduced to a value technically as low as possible, current values in this respect being one to maximally almost three times the real time relative to the play duration of a CD, depending on the nature on the music/data carrier concerned (see Table on page 1).
If premastering procedures were necessary or if the type of music/data carrier used failed to provide adequate performance values for subsequent steps in processing, the useful and control information is subsequently copied onto a music/data carrier which ensures a reading speed and data security as high as possible (see
FIG. 7
, page 43). Depending on the infrastructure and requirements on the CD plant exabyte tapes, CD/WO disks, MO disks or also U-matic tapes currently find application. (all of these being simply termed “transfer media” in the following). The transfer media produced in premastering contain in general all useful information existing later on the CD (main channel and subcode data) supplemented by control data (e.g. DDP) for later mastering. Useful and control information may also be held on separate music/data carriers (e.g. useful contents on exabyte tape, control information on floppy disk).
An error protocol may be included in the writing procedure comparable to the procedure in reading-in the useful information when the transfer is made to other music/data carriers.
Once premastering has been completed and the transfer media has successfully passed through all steps in checking and processing the useful information stored thereon needs to be transferred to an optical intermediate carrier (a light-sensitive glass disk, termed glass master in the following) with which in further steps in processing an electroplate replicate is implemented.
Mastering
Glass disks having special mechanical and optical properties serve as the intermediate carrier. In preparing for mastering the glass disks are cleaned and coated with a very thin, tight tolerance light-sensitive layer which is subsequent baked by the application of heat in corresponding devices. The methods and equipment used for this purpose are similar to those employed by the semiconductor industry. Due to the high demands on the cleanliness of the materials used, the tight tolerances on thickness of the light-sensitive coating and the necessary stability in processing, this procedure is highly time and hardware intensive.
The glass disks once finished in preparation are inserted in a laser-beam recorder (LBR) prior to commencement of the actual mastering process, an interface (LBR interface) as well as readers for the transfer media being connected to the laser-beam recorder. For this purpose use is made typically of CD, exabyte or U-matic drives in accordance with the transfer media as listed above (see
FIG. 1
, page 37 and
FIG. 3
, page 39). The task of the laser-beam recorder, its control hardware, the LBR interface and the connected readers is to convert the useful and control information held on the transfer media into a data stream required by the desired type of CD and to transfer the logic data structure needed for the corresponding type of CD to the light-sensitive coating on the glass disk.
For this purpose the laser beam impinging the rotating glass disk is modulated in an interplay of useful and control information with the aid of the LBR interface and the control hard/software of the laser-beam recorder. The result is a continuous sequence of light pulses the length and gaps of which are precisely defined as formed on the glass disk as a spiral chain of exposed and non-exposed positions. In this arrangement, converting the useful and control information into a continuous data stream and the speed in reading the transfer media need to be intimately adapted to each other. Since the laser-beam recorders employed need a continuous data stream as a mandatory requirement, keeping to an average minimum data rate for the readers and transfer media employed is necessary. By current state of the art standards it is the reading speed which dictates the speed at which the desired data stream can be written on the glass disk.
Due to the non-reversibility of this transfer action uncorrected reader errors, interruptions in the data stream to the laser-beam recorder or errors in transfer in the laser-beam recorder result in a glass master which is useless for further steps in processing. Once an error has been written onto the glass master, caused by non-correctable bit errors or by an interruption in the data stream, no correction is possible in the same working procedure. If such non-correctable errors have been detected, the procedure needs to be discontinued and the complete mastering process repeated.
Glass masters exposed with zero error are developed, provided with a thin metal coating and passed on to the subsequent electroplating.
The transfer media used for mastering are in general subsequently deposited in manually administered libraries in the CD plant in case subsequent mastering orders are required.
II) Disadvantages of Prior Art
Even when employing transfer media having a comparitively high read/write speed within the bandwidth of music/data carriers as usual in the branch (CDWO, MO disks, exabyte tapes) the data rates of approx. 3.5 Mbit/sec. currently achievable are low compared to the technical/physical possibilities of the laser-beam recorder
Günther Christian
Martens Wolfgang
Redder-Pohlmann Artur
Feiereisen Henry M.
Peyton Tammara
Sonopress Produktionsgesellschaft für Ton- und Informationsträge
LandOfFree
System and method for recording digital data on glass master... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method for recording digital data on glass master..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for recording digital data on glass master... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2868910