Abstract: A tape cartridge library that is equipped with a cleaning device is described. The tape cartridge library essentially includes a plurality of tape cartridges each possessing recording tape media. A plurality of tape drives that read and write data to and from each of the tape cartridges. A tape cleaning drive incapable of transferring data to and from the recording tape media which is independent of the tape drives, the tape cleaning drive disposed entirely within the tape cartridge library. The tape cleaning drive automatically receives one of the tape cartridges and cleans its respective recording tape medium when a predetermined reason for cleaning the tape cartridge is justified.

Abstract: SMR disk drives with hybrid E-regions that include a nonvolatile solid state memory E-region in addition to the magnetic media E-regions on disk are described. The memory E-region can be used in operations that will be referred as destaging and/or restaging to sequentialize sets of exception records to reduce the time and energy spent in executing seeks in the disk E-region. The ratio of the size of the solid state memory E-region to the total E-region capacity on the disks can be optimized for selected applications according to the invention using tradeoffs between performance and cost. For example, an embodiment with a memory E-region size that is 10% of the total disk E-region capacity achieves substantial performance enhancement over a disk-only E-region implementation and also results in smaller costs than would be required in a NAND-only memory E-region.

Abstract: SMR disk drives with hybrid E-regions that include a nonvolatile solid state memory E-region in addition to the magnetic media E-regions on disk are described. The memory E-region can be used in operations that will be referred as destaging and/or restaging to sequentialize sets of exception records to reduce the time and energy spent in executing seeks in the disk E-region. The ratio of the size of the solid state memory E-region to the total E-region capacity on the disks can be optimized for selected applications according to the invention using tradeoffs between performance and cost. For example, an embodiment with a memory E-region size that is 10% of the total disk E-region capacity achieves substantial performance enhancement over a disk-only E-region implementation and also results in smaller costs than would be required in a NAND-only memory E-region.

Abstract: A hybrid disk drive transfers a data stream to or from a host at an increased data transfer rate by time-multiplexing the data-carrying capacity of the system bus connecting the host and the disk drive. A portion of the data stream is stored on a non-volatile solid state memory device in the disk drive and a portion is written to a magnetic storage disk. The portion of the data stream written to the storage disk may be written on data tracks that are separated by empty data tracks corresponding to the data stored in the non-volatile solid state memory device.

Abstract: A data archiving apparatus includes an autoloader for automated transfer of data tape cartridges between at least one tape drive and storage locations of at least one cartridge storage magazine. One or more hard disks is mounted within the autoloader apparatus. The hard disk is connected for data transfer between the hard disk and the tape drive so that data caching can be accomplished during the data archiving process. Interface controls for both the tape drive and the one or more hard disks is provided within the housing of the data archiving apparatus to permit simultaneous operation of the hard disk and the tape drive and for data transfer there between. The hard disks may be exchanged by a user to increase data storage capacity.

Abstract: A method of transferring data of one or more rotatable data storage devices includes but is not limited to rotating the at least one rotatable data storage device; transferring the data between a plurality of stationary data transfer heads and the one or more rotatable data storage devices; and using one or more computer programs to determine which of the plurality of stationary data transfer heads are to be used to transfer a first portion of the data between the plurality of stationary data transfer heads and the one or more rotatable data storage devices and the direction in which the first portion of the data is to be transferred. In addition to the foregoing, other method aspects are described in the claims, drawings, and text forming a part of the present application. Other methods and apparatuses are also disclosed.

Abstract: A duplication device is provided. When content is duplicated by recording, in a recording medium of a recording destination, the same content as content recorded in a recording medium of a duplication source, even if a reading speed is slower than a writing speed, the duplication device can reduce a duplication time as much as possible. The duplication device 100 reads a reading portion of content from an optical disc D in which content is recorded, and in parallel to this reading, downloads a transmission portion which includes a portion of content other than the reading portion, from a distribution server 200, and records the read reading portion and the downloaded transmission portion in the hard disc 106 at a speed faster than a speed of reading the reading portion.

Abstract: Systems and methods for retrieving data stored on a peripheral storage device such as a magnetic tape drive or disk drive include string searching using the peripheral storage device resources without transferring data to the requesting host computer and transferring only data blocks with matching data to the associated host computer to conserve host resources and data channel and/or network bandwidth.

Abstract: According to one embodiment, a magnetic disk medium is pre-formatted on both the surfaces by magnetic transfer. Sectors with the same sector number on the front surface and the rear surface of the magnetic disk medium are arranged at positions shifted by a predetermined angle associated in advance with determination target information.

Abstract: A magnetic transfer device and method are provided. A magnetic field generating structure comprises a pair of permanent magnets connected to a return yoke. Respective magnetic poles of the magnets, of a different polarity from one another, oppose each other with a conjoined body disposed therebetween. The magnetic field generating structure is moved from a position at an outer periphery of the conjoined body, to a position at an inner periphery of the conjoined body, and then moved from the position at the inner periphery across the conjoined body toward the outer periphery, to a position outside of the conjoined body. The return yoke is positioned at a radially more outward position, toward the outer periphery, than are the permanent magnets. The movement of the magnetic field generating structure is carried out while maintaining a constant distance from the rotating conjoined body.

Abstract: An information processing apparatus includes a communication unit configured to receive, from a reproduction device that reproduces content recorded on a loaded recording medium, content forming information regarding the structure of the content; a degree-of-similarity calculation unit configured to compare the content forming information received by the communication unit with content forming information registered in advance for each package of an information recording medium in a predetermined database and calculate a degree of similarity between the content forming information received by the communication unit and the content forming information registered in advance in the database; and a package determination unit configured to determine the package of the information recording medium loaded into the reproduction device by using the degree of similarity calculated by the degree-of-similarity calculation unit.

Abstract: According to one embodiment, a stamper has three-dimensional patterns in a dummy region. The three-dimensional patterns have a repeatable run out of 1 nm or less between the 15th and 40th orders when the rotational frequency is the first order as a reference.

Abstract: Included are embodiments for providing communications data. At least one embodiment of a method receiving data associated with a communications session, the communications session including a first communications stream and a second communications stream, wherein the first communications stream and the second communications stream are received in a receiving order and recording at least a portion of the communications session. Some embodiments include receiving a request to provide, from the recording, at least a portion of the first communications stream in a visual format and providing at least a portion of the first communications stream in the visual format.

Abstract: A magnetic transfer method includes a conjoined body formation step of stacking a transfer master storing transfer information on a transfer receiving body. Air between contact surfaces of the transfer master and transfer receiving body is pushed out in the direction of a non-pressurized area by pressurizing the stacked transfer master and transfer receiving body, to form the conjoined body. The method further includes a transfer step of, by bringing a magnetic field generating module close to the conjoined body, and applying a magnetic field, carrying out a magnetic transfer of the transfer information from the transfer master to the transfer receiving body. A surface roughness of smooth portions of the transfer master in which no transfer information is formed, and the surface roughness of the transfer receiving body, is 1 nm or less.

Abstract: To limit the time capable of reproducing a plurality of contents as a whole recorded on a recording medium. Provided herein are a recording medium on which a plurality of contents and reproduction-enabled time which is a period of time for allowing a user to freely reproduce the plurality of contents as a whole are recorded, a reproduction device having an acquisition unit which acquires the reproduction-enabled time and a reproduction inhibit unit which inhibits the reproduction of each of the contents when the accumulated reproduction time of the plurality of contents as a whole exceeds the acquired reproduction-enabled time during the reproduction of each of the contents.

Abstract: According to one embodiment, a magnetic recording medium on which servo data is recorded by magnetic transfer recording, the medium includes a data recording area in which data is recorded on a plurality of data tracks extending in form of concentric circles, and a servo area comprising the servo data corresponding to the data tracks. The servo data includes a plurality of burst patterns for tracking detection, which are arranged in a circumferential direction of the data tracks, and the burst patterns comprise a number of recording crests which differs depending on a radial position on the magnetic recording medium.

Abstract: The servo master includes a membrane having a first surface and a second surface; a plurality of stamp areas which are disposed on the first surface, each of the plurality of stamp areas including a magnetic layer patterned with servo patterns to be magnetically transferred to a magnetic recording medium; and a pressing members which are disposed on the second surface, each of the plurality of pressing members being operable to apply pressure to a corresponding stamp area of the plurality of stamp areas.

Abstract: Provided are a computer program product, system, and method for managing write operations to an extent of tracks migrated between storage device. An operation is processed to migrate an extent of tracks from the second storage to the first storage. A determination is made as to whether an extent object exists for the extent to migrate. The extent object exists if the extent was previously migrated from the first storage to the second storage at a previous time. The extent object includes for each track a write indicator indicating whether the track was updated in the second storage since the previous time when the extent was previously migrated to the second storage. In response to determining that the extent object exists, a determination is made of the tracks in the extent having the write indicator indicating that the track was updated in the second storage since the previous time. The data for the determined tracks is copied from the second storage to free locations in the first storage.

Abstract: A master disk for magnetic transfer of a reference servo signal in a spiral mode, having a pattern including a plurality of dots groups, which are disposed at different radial positions of the master disk with a first pitch, and correspond to the reference servo signal in the spiral mode. Each of the plurality of dot groups includes a plurality of dots, successively disposed with a second pitch along a circumferential direction of the master disk at a same one of the radial positions. Each of the plurality of dots is of a ferromagnetic material, and has four sides, two opposing sides thereof extending in the circumferential direction, and the other two opposing sides thereof extending in a radial direction of the master disk.

Abstract: A method is presented of erasing, in a document data processing device, a stored information pattern on a rewritable data carrier that is accessible by a data processing facility of the document data processing device. The document data processing device includes primary processes for processing document data, wherein data may be stored on the data carrier, and secondary processes for erasing stored data, through overwriting a selected storage area of the carrier by a shredding pattern. According to the method, the primary and secondary processes are run asynchronously, e.g., the secondary processes are run in background, in order not to hinder the primary processes. In a particular embodiment, an initial shredding run is made directly after a file is no longer used, and additional shredding runs are made in background.

Abstract: The content copying system pertaining to the present invention is a content copying system in which multiple devices (11-14) cooperate to copy content to a removable recording medium (31). The first device (11) comprises a writing unit for writing first management data which includes content identifiers (hash1˜hash4) to the removable recording medium (31). A second device (12) storing content pieces (ep2, ep4) copies content pieces (ep2, ep4) corresponding to the content identifiers (hash2, hash4) included in the first management data to the removable recording medium (31). Another second device (13) which has a content piece (ep3) stored thereon copies, to the removable recording medium (31), the content piece (ep3) corresponding to the content identifier (hash 3) written to the removable recording medium (31).

Abstract: A hard disk controller includes a track counter which counts the number of times each of a plurality of tracks included in each of a plurality of disks is accessed and a processing unit which compares each of a plurality of count values obtained by the counting performed by the track counter with an access reference value, and backs up data recorded on at least one of the plurality of tracks. The at least one track has a count value equal to or greater than the access reference value from among the plurality of count values.

Abstract: A recording device including: a recorder recording data onto a recording medium on which tracks as units of audio data are grouped and managed by management information; and a controller generating an image file in which image data associated with one of each track recorded on the recording medium and each group managed by the management information is collected, and recording the image file onto the recording medium by the recording means.

Abstract: In a virtual disk library device access of data stored in a tape can be conducted at a high speed with a high-speed archiving process from a disk to the tape in units of LUs maintained. The efficiency of update of the data stored in the tape can be improved. In this system, when the data stored in the tape is to be accessed with a high-speed archiving process in units of LUs from the disk to the tape maintained, a disk staging process is performed in the unit of a page that is smaller than the unit of an LU, and accordingly, high-speed access can be implemented. In addition, when an update process for the data (LU) stored in the tape is performed, the host can be responded by only staging an update target page of the LU, and a prior disk staging process is performed for the remaining pages of the LU in the background. Accordingly, when the data is re-stored in the tape, immediately storing the data in the tape can be performed without performing a staging process.

Abstract: A method for making a master disk to be used for nanoimprinting patterned-media magnetic recording disks uses sidewall lithography. In one implementation, the master disk substrate has a first pattern of concentric rings formed on it by sidewall lithography, followed by a second pattern of generally radially-directed pairs of parallel lines, also formed by sidewall lithography, with the pairs of parallel lines intersecting the rings. An etching process is then performed, using the upper pattern as an etch mask, to remove unprotected portions of the underlying concentric rings. This leaves a pattern of pillars on the substrate, which then serve as an etch mask for an etching process that etches unprotected portions of the master disk substrate. The resulting master disk then has pillars of substrate material arranged in a pattern of concentric rings and generally radially-directed pairs of parallel lines.

Abstract: Provided is a tape recorder that has a tape including at least one partition and that controls access to the tape. The tape recorder includes: means for identifying a position of data on the tape; means for sequentially reading necessary data areas in the data; means for sequentially copying the necessary data areas to the beginning of an empty area on the tape; means for creating a continuous front empty area formed of unnecessary data areas and copy source areas of the necessary data areas on the tape; and means for moving a beginning of the partition (BOP) to a position immediately after the front empty area and for updating the position information on the beginning of the partition.

Abstract: A master disk for magnetic transfer of a reference servo signal in a spiral mode, having a pattern including a plurality of dots groups, which are disposed at different radial positions of the master disk with a first pitch, and correspond to the reference servo signal in the spiral mode. Each of the plurality of dot groups includes a plurality of dots, successively disposed with a second pitch along a circumferential direction of the master disk at a same one of the radial positions. Each of the plurality of dots is of a ferromagnetic material, and has four sides, two opposing sides thereof extending in the circumferential direction, and the other two opposing sides thereof extending in a radial direction of the master disk.

Abstract: A data storage device includes: a recording medium that has two or more system data recording areas where system data are recorded on a multiple basis, and a user data recording area where user data is recorded; a head that writes and reads data into and from the recording medium; and a system data update control section that causes the head to update the system data on the recording medium. The system data update control section causes the head to record new system data on a multiple basis in another sub-record area that is alternately selected at each update to the new system data over the two or more system data recording areas when each the two or more system data recording areas is divided into two sub-record areas, and read the new system data from the another sub-record area to confirm that the new system data is recorded correctly.

Abstract: A plurality of digital hard disc drives (201 and 209) are provided (101) that are intended to each receive precisely identical digital cinematic content. One of these digital hard disc drives is identified (102) as a primary source module (202) and a determination (103) then made regarding which of a single pass and a dual pass write process to use to write the digital cinematic content from the primary source module to each remaining one of the plurality of digital hard disc drives. This selected write process is then used (104) to write the digital cinematic content to each remaining one of the plurality of digital hard disc drives.

Abstract: A method for maintaining paired data between tape cartridges and linking the paired data to through medium auxiliary memory devices is presented. One method includes providing a first tape cartridge possessing a first medium auxiliary memory device and a first tape medium and a second tape cartridge possessing a second medium auxiliary memory device and a second tape medium. Data maintained on the first tape medium can be copied to the second tape medium. A first record can be stored on the first medium auxiliary memory device indicating that data on the first tape medium was copied to the second tape medium. Likewise, a second record can be stored on the second medium auxiliary memory device indicating that data on the second tape medium originated from the first tape medium.

Abstract: A method for recovering data from a failed tape cartridge is presented. The reliability of a tape cartridge is assessed via the number of read errors encountered. If the number or read errors is excessive, the tape cartridge is deemed unreliable and the tape cartridge is restricted from storing anymore data. A search is performed to look for duplicate data and if found a copy of the duplicate data is stored to a replacement tape cartridge. The replacement tape cartridge assumes all identity of the original failed tape cartridge.

Abstract: A method and system for manipulating a spin state of each disk in a drive array is disclosed. In one embodiment, a method includes monitoring input/output (I/O) requests to each disk drive in a disk array and identifying any disk drive as an inactive disk drive based on a number of I/O requests directed to said any disk drive for a given time interval. The method further includes moving data from the inactive disk drive to an active disk drive having a free disk space to store the data and updating metadata associated with the data using a log-structured file system for the disk array. Further, the method includes manipulating a spin state of the inactive disk drive by spinning down the inactive disk drive to conserve power. Furthermore, the method includes redirecting subsequent I/O requests for the inactive disk drive to the active disk drive by accessing the metadata of the log-structured file system.

Abstract: A master-disk producing device produces a master disk with master-disk identification information added. A disk producing device produces a first disk with the master-disk identification information added, using the master disk with the master-disk identification information added. A first disk device obtains, after the first disk with the master-disk identification information added is mounted, first correction information from a correction-information storing device based on the master-disk identification information of the first disk.

Abstract: A method and system for fabricating a magnetic recording device are described. The method and system include providing a mask layer on the magnetic recording device and imprinting a pattern in the mask layer to form a mask. The method and system also include transferring the pattern from the mask to the magnetic recording device. In another aspect, the method and system include providing a malleable mask layer on the magnetic recording device. In this aspect, the method and system also include depressing an imprint mask into the mask layer and curing the mask layer while the imprint mask is depressed into the mask layer to provide a mask having a pattern. The pattern may correspond to a read sensor and/or a perpendicular magnetic recording pole. The method and system also include transferring the pattern from the mask to the magnetic recording device.

Abstract: On a magnetic recording medium, M sets of burst patterns are formed along a direction of rotation of a substrate in each burst pattern region. Each burst pattern is formed so as to include two types of burst signal units that have an equal length along a radial direction of the substrate. In a predetermined range, (2M) centers in the radial direction of the burst patterns are present at intervals of (1/N) times the track pitch in the radial direction. The predetermined range has a length along the radial direction of (2M/N) times the track pitch. M or N is a natural number of 2 or higher. The two types of burst signal units are formed of non-recording regions and end regions of the burst signal units overlap in the radial direction in at least one part region of the substrate.

Abstract: Aiming to suitably balance, when backing up data to a magnetic tape, search time and writing/reading performance depending on the purpose of the backup, provided is a disk array apparatus including a disk device having hard disks, a magnetic tape device including a magnetic tape to which data to be backed up is written, and a control unit performing writing and reading processings of data between the disk device and the magnetic tape device. The control unit includes an FM (file mark) interval managing unit which receives a purpose of use when backing up the data on the magnetic tape, and from FM intervals which is held in association with the purpose of use thus received and which indicates an interval of recording FMs on the magnetic tape, acquires an FM interval corresponding to the purpose of use thus received, and transmits the acquired FM interval to the control unit.

Abstract: Method and apparatus for logging of data within a data storage system, such as a tape drive library. The tape drive library includes a central storage (memory) providing storage space assigned to each tape drive in the tape drive library and allowing each tape drive to directly store data there, that is to log data files. The logging of the data files is at the instigation of each tape drive and not via polling, so as to perform logging synchronous with tape drive events. In one version, the tape drives are coupled to the central storage via an Ethernet network and the log files conform to a standard file protocol, such as a network file system.

Abstract: An information recording device according to the present invention includes an HDD 5, a DVD 6 and a VCR 7. During transferring and recording information from DVD 6 onto VCR 7, a transfer control circuit 20 short-circuits between an input node and an output node. Accordingly, an image signal line L1 or L2 is electrically connected to an image signal line L3 through a switch SW and transfer control circuit 20. Namely, information is transmitted to the VCR without providing a direct information transmission path from DVD 6 to VCR 7. The configuration according to the present invention enables bidirectionally transferring information among HDD 5, DVD 6 and VCR 7 with a single switch, thereby enabling dubbing with a simple configuration.

Abstract: A method for processing an analog video signal that represents a work for which rights information is asserted. The signal includes a rights assertion mark (RAM) in the video portion of the signal within the visible picture such that capture of the picture will include the mark. The signal also includes copy control information (CCI) bits in the vertical blanking interval of the signal for representing copying and redistribution rules. If the RAM is present and the CCI bits are present, then the copying and redistribution rules represented by the CCI bits are applied. If the RAM is present but the CCI bits are not, then the most restrictive copying and redistribution rules that can be represented by the CCI bits are applied.

Abstract: A method of the present invention duplicates data of a source medium to target media. The source medium is stored ground data and effective data, wherein the ground data are repeated to fill up the source medium and the effective data overwrite some of the ground data. Next, reading data of the source medium and comparing the data to the ground data. If the data are not as same as the ground data, then copy the data to the at least one target medium. If the data are as same as the ground data, then read the next t data of the source medium and repeating the comparing step.

Abstract: A holder unit for use in a transfer apparatus that causes a surface of a transfer master and a surface of a slave medium to be in direct contact with each other and transfers information on the transfer master surface to the slave medium surface. The holder unit includes a pair of gripping members, movable toward and away from each other, for holding the transfer master. The transfer master is stuck firmly on either or both of the pair of gripping members through or without an elastic member.

Abstract: In a virtual disk library device access of data stored in a tape can be conducted at a high speed with a high-speed archiving process from a disk to the tape in units of LUs maintained. The efficiency of update of the data stored in the tape can be improved. In this system, when the data stored in the tape is to be accessed with a high-speed archiving process in units of LUs from the disk to the tape maintained, a disk staging process is performed in the unit of a page that is smaller than the unit of an LU, and accordingly, high-speed access can be implemented. In addition, when an update process for the data (LU) stored in the tape is performed, the host can be responded by only staging an update target page of the LU, and a prior disk staging process is performed for the remaining pages of the LU in the background. Accordingly, when the data is re-stored in the tape, immediately storing the data in the tape can be performed without performing a staging process.

Abstract: The present invention is a method for implementing a storage system. The storage system may include a disk array having a disk drive pair which includes a solid-state disk drive and a hard disk drive. The method may include the step of copying a data subset of a data set from the hard disk drive to a spare solid-state disk drive during a solid-state disk drive rebuild process. The data subset includes a first amount of data and the data set includes a second amount of data, where the first amount of data is less than the second amount of data. The method may further include the step of receiving a read request from a host server requesting the data subset. The method further includes the step of directing the read command to the spare solid-state disk drive. The method may further include the step of, prior to completion of copying of the data set from the hard disk drive to the spare solid-state disk drive, reading the data subset from the spare solid-state disk drive based upon the read command.

Abstract: A method and an apparatus for copying data of a disc drive are provided. The method includes: determining whether the first disc drive has a predetermined jumper pin connection by identifying which of a plurality of jumper pins in a jumper block of the first disc drive are connected, the jumper block being used to determine an operation mode of the first disc drive; transmitting a copy command from the first disc drive to the second disc drive if the first disc drive has the predetermined jumper pin connection; and copying data recorded in the first disc drive to the second disc drive in response to the copy command. Accordingly, it is possible to copy data recorded in a first hard disc drive (HDD) to a second HDD without the aid of an additional host.

Abstract: Disclosed is a low power consumption storage array. Read and write cycles are separated so that a multiple disk array can be spun down during periods when there are no write requests. Cooling fans are operated with a pulse-width modulated signal in response to cooling demand to further reduce energy consumption.

Abstract: A data storage device includes: a recording medium that has two or more system data recording areas where system data are recorded on a multiple basis, and a user data recording area where user data is recorded; a head that writes and reads data into and from the recording medium; and a system data update control section that causes the head to update the system data on the recording medium. The system data update control section causes the head to record new system data on a multiple basis in another sub-record area that is alternately selected at each update to the new system data over the two or more system data recording areas when each the two or more system data recording areas is divided into two sub-record areas, and read the new system data from the another sub-record area to confirm that the new system data is recorded correctly.

Abstract: A playback unit (3) reproduces contents which are recorded on a video cassette tape (2), and a recording unit (6) records the contents on another video cassette tape (7) and, simultaneously, an erasing unit (5) erases the contents from the video cassette tape (2). Thereby, the copy-inhibited contents recorded on the video cassette tape (2) can be transferred to the other video cassette tape (7) without copying the contents.

Abstract: According to one embodiment, a magnetic recording media includes a substrate having recording tracks and separating regions separating the recording tracks, the separating regions having patterns of protrusions and recesses formed therein, and a recording film deposited on the substrate, in which a difference in height between a top of the recording track and a top of the separating region is 2 nm or more and 7 nm or less, and a difference in height between the top of the recording track and a bottom of the separating region is 10 nm or more.

Abstract: A contact magnetic transfer (CMT) master template has a flexible plastic film with a planarized top or upper surface containing magnetic islands separated from one another by nonmagnetic regions. The flexible plastic film is secured at its perimeter to a silicon annulus that provides rigid support at the perimeter of the film. The plastic film is preferably polyimide that has recesses filled with the magnetic material that form the pattern of magnetic islands. The upper surfaces of the islands and the upper surfaces of the nonmagnetic regions form a continuous planar surface. The nonmagnetic regions are formed of chemical-mechanical-polishing (CMP) stop layer material that remains after a CMP process has planarized the upper surface of the plastic film.

Abstract: A magnetic transfer apparatus and method includes air supply for supplying air into a space above a peripheral portion of a double-sided slave disc beyond a second master disc in an air-tight chamber formed when a first disc holder holding a first master disc and the slave disc in contact and a second disc holder holding the second master disc are brought into contact with each other so as to hold and sandwich the slave disc between the first and second master discs, the air supply being controlled to take place at least either during formation of the air-tight chamber or during opening the air-tight chamber.