JPH04326420A - Magnetic tape storage and its control system - Google Patents

Abstract

PURPOSE:To attain the control of other devices connected indirectly by a computer with a local interface different from the interface for connection to a computer for a magnetic tape storage serving as an external storage. CONSTITUTION:A magnetic tape storage is provided with a self-diagnositic function of an external bus and a slave device control function. Thus the command received from a host computer 20 is converted into a local command and the device connected to a local bus is controlled by the protocol of a local interface 19. The devices connected indirectly via the local bus can be operated by a computer. Furthermore the computer can work independently of the copy process in such operations as the tape copying, etc., that require a long time for execution.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a magnetic tape storage device that digitally stores data on magnetic tape as an external storage device for a host computer, and a magnetic tape storage device control system using a plurality of such magnetic tape storage devices. In particular, digital VTR and D
The present invention relates to a magnetic tape storage device using an AT (digital audio tape recorder) or the like and its control system.

0002

[Prior Art] The external storage device of a host computer is
They are broadly divided into disk devices, which provide relatively high-speed access to data, and tape devices, which have a larger storage capacity than disk devices, and are used in fields that take advantage of their respective characteristics. By the way, recently, digital VTRs and DATs, which digitally record digital data such as videos and music on magnetic tape, have been introduced.
Magnetic tape storage devices such as Because positioning using absolute addresses is possible, applications as external storage devices for computers have been considered, and development is progressing.

These magnetic tape storage devices for computers require a connection means with the computer, high data input/output speeds, and high data reliability. and magnetic tape storage for music. In other words, computer data is different from video and music data in that there is no correlation between the preceding and following data, so in addition to the error correction means used for video and music, error correction using Reed-Solomon codes (C3 error correction) is used. Efforts have been made to prevent data loss due to burst errors during playback and improve the reliability of playback data.

Fields of use of these magnetic tape storage devices include use as a backup device for hard disks, storage and distribution of large-capacity data such as medical image data, weather data, and CAD data, and as a FAX reception and recording device. Uses are listed. Now, when focusing on the distribution of large amounts of data, a dubbing device is needed that can duplicate magnetic tapes on which data is recorded in a short period of time. For example, as described in Japanese Patent Application Laid-Open No. 1-205762, a copy of a magnetic tape on which music data is recorded is
The copy source tape device outputs the digital data converted by the signal processing circuit to the copy output terminal, and the copy destination tape device records the data received from the input terminal on the magnetic tape via the signal processing circuit. A method called digital copying is used, but in order to copy magnetic tape as computer data, it is necessary to copy data after C3 error correction as described above in order to avoid data loss due to burst errors. is desirable.

[0005] In distributing large amounts of data as described above, by connecting a plurality of magnetic tape storage devices, one copy source magnetic tape storage device can be transferred from one copy source magnetic tape storage device to multiple copy destination magnetic tape storage devices. A system that can perform copying at the same time is expected. By the way, when a magnetic tape storage device is connected to a host computer and used as a data input/output device, high-speed one-to-one data transfer is required, so for example, SCSI (Small Computer System Interface) It is common to use standard interfaces such as Therefore, when copying magnetic tape using an interface for connecting to a computer, the interface bus is used to transfer copy data during the period required to copy the magnetic tape, so the interface bus is not connected to the bus. There is a problem in that it becomes impossible to operate other devices. on the other hand,
When transferring data from a storage device connected to a computer to another storage device, connecting each storage device directly eliminates the need for computer intervention. It becomes possible to operate other devices in the computer, and during this time it can also be assigned to the internal processing of the computer. Therefore, it is effective for a magnetic tape storage device that can be used by connecting to a computer and has a copy function to multiple drives to have a different external interface (hereinafter referred to as a local interface) in addition to the interface for connecting to the computer. It is.

[0006]

[Problem to be solved by the invention] In the case of a magnetic tape storage device that is not a dedicated dubbing machine but can be used as an external storage device for a computer and also has a dubbing function, it is not a dedicated dubbing machine. Magnetic tape storage devices can be operated by operating commands sent from a computer. However, a magnetic tape storage device that is not connected to a computer but is connected to a magnetic tape storage device (hereinafter referred to as a master device) connected to a computer by an interface bus for copying (hereinafter referred to as a local bus) (hereinafter referred to as a slave device) cannot be operated by an operation command from a computer. Normally, a computer recognizes the various devices connected to it, gives each device an identification symbol such as a number, and by specifying that symbol determines which device the command sent by the computer is directed to. be able to. However, since slave devices are not directly connected to the computer, they are not recognized by the computer and cannot be selected or operated by the host computer.

[0007] The present invention has been made in view of the above points.
Its purpose is to enable slave devices that are indirectly connected to a computer via a local bus to be controlled by operating commands from the computer.

[0008]

[Means for Solving the Problem] A master device connected to a computer can check the number of slave devices connected to itself via a local bus, and also allows the master device to operate the slave devices. An interface control circuit is provided. This interface control circuit has the function of investigating its own connection state and determining whether it is in a slave state or a master state, and when it is a master device, it identifies it to the slave device. By giving a symbol, a slave device connected to a master device can be specified from a computer. The slave device is treated as a child device of the master device, and from the computer,
The slave device is configured to be selected based on the identification symbol of the master device and the identification symbol of the slave device assigned by the master device.

[0009]

[Operation] Each magnetic tape storage device checks the connection status of its own external bus, determines whether it is a master device or a slave device, and if it is connected to a computer, the master device It is determined that If the device is the master device, the device checks the number of connected slave devices and gives each slave device an identification symbol. Selection of a slave device from the computer is performed based on the identification code of the connected master device and the identification code of the slave device assigned by the master device. The master device that receives the command from the computer determines whether the received command is directed to itself or to a slave device that it manages, and if the command is directed to itself, performs processing according to the command, Send the status back to the computer. In addition, if the received command is for a slave device that it manages, it converts it into a command defined by the local interface (hereinafter referred to as a local command) so that the received command can be processed, and sends it to the local Send to the slave device specified by the bus's transmission protocol. The slave device that receives local commands from the master device performs processing corresponding to each command and returns the execution results to the master device, and the master device sends the notified execution results to the computer. It becomes possible to control slave devices that are indirectly connected to the local bus.

0010

Embodiment As an embodiment of the present invention, a case will be described in which a DAT recorder developed as an external storage device for a computer to which DAT is applied is used. The DAT recorder used in this embodiment uses a rotary head that is mounted on the circumference of a cylinder and rotates together with the cylinder like a VTR, and records data obliquely to the running direction of the magnetic tape. Further, the DAT recorder uses an azimuth recording method, in which adjacent tracks are recorded with different azimuth angles, and two heads of + (plus) azimuth and - (minus) azimuth alternately trace the tracks. Each head reads the ATF (auto track finding) area of a track recorded at an azimuth that matches its own azimuth, applies servo, and reads the PCM area and subcode area. Also, when recording, use a head that is slightly wider than the track width, so that when recording the next track, the previously recorded track and new track are slightly overlapped. As a result, the previously recorded track is controlled to have the track width specified by the standard. This DAT recorder has 64 tracks as one group, and performs recording and reproduction on a tape in units of two groups. Gap tracks on which no data is written are provided before and after the above groups, and even if rewriting is performed in group units, it will only destroy the gap tracks of the adjacent group and will not affect the data area. This tape format makes it possible to partially rewrite the magnetic tape.

FIG. 1 shows a system configuration diagram of the DAT recorder of this embodiment. In the figure, 1 is a cylinder to which a rotary head is attached, 2 is a cylinder motor that rotates this cylinder, 3 is a capstan motor that runs the tape in a constant manner, 4 is a reel motor that performs fast forwarding/rewinding, and 5 is each of these motors. A servo circuit that controls the motors 2 to 4; a recording/reproducing circuit 6 that records/reproduces signals using a rotating head;
7 is a signal processing circuit that processes signals according to the DAT format, 8 is a subcode control circuit that also processes signals according to the DAT format, and 9 is a drive control circuit that instructs the operation mode and controls the drive of the mechanism. , 10 is a mechanical drive circuit that receives this signal and drives the mechanism, 11 is a loading motor that is controlled by the mechanical drive circuit 10 and used for loading the tape, and 12 is an error correction code according to the DAT format. 13 is a layered ECC (error checking and correcting) provided to strengthen error correction for use in computers;
The circuit 14 is for data storage and layered ECC encoding/
A memory for decoding, 15 a memory control circuit that controls reading data from and storing data in the memory 14, 16 a system control circuit that controls the entire DAT recorder, and 17 a host computer. 18 is a SCSI circuit which is an interface for connection with a host computer;
9 is a local interface which is an interface for connecting with other DAT recorders; 20 is a SCSI circuit 1
This is a host computer connected to the DAT recorder via 8.

Next, the basic operation of the DAT recorder will be explained. <Loading operation> When a detection circuit (not shown) detects that a tape cartridge is set in the device (DAT recorder), the system control circuit 16 drives the loading motor 11 to pull out the tape from the tape cartridge and into the cylinder 1. Wrap it around. When the tape is loaded, the system control circuit 16 sends a signal to the drive control circuit 9 to perform rewind, and the drive control circuit 9 sets the servo circuit 5 to rewind mode. The servo circuit 5 instructs the reel motor 4 to rewind, and rewinding of the tape is started. When the tape is rewound and the drive control circuit 9 detects that the tape has been rewound to the transparent part, it sets the servo circuit 5 to a stop mode and sends a message to the system control circuit 16 indicating that the tape has been rewound. Let me know. Next, the system control circuit 16 instructs the drive control circuit 9 to search for an area where tape information is recorded. As a result, the drive control circuit 9 sets the servo circuit 5 to high-speed search mode and drives the reel motor 4 and cylinder motor 2. At this time, by controlling the cylinder motor 2 by the servo circuit 5 so that the tape running speed is intermittently the same as that during recording/reproduction, data can be reproduced intermittently at high speed. The data thus intermittently reproduced is extracted by the signal processing circuit 7, the data is inspected by the subcode control circuit 8 and the drive control circuit 9, and the contents of the subcode data and PCM-ID are read. Search for the beginning position of the area where tape information is recorded. When the head position of the desired recording area is detected, the drive control circuit 9 temporarily puts the servo circuit 5 into the stop mode, rewinds the overrun tape a little in the rewind mode, reads out the tape information in the playback mode, and After reading the tape information, positioning is performed at the beginning of the data area.

<Reproduction operation> In response to a data reproduction request,
The drive control circuit 9 puts the servo circuit 5 into play mode,
The signal processing circuit 7 is put into reproduction mode. The servo circuit 5 is
8.1 which controls the reel motor 4 and is defined by the magnetic tape.
The servo circuit 5 controls the number of rotations of the cylinder 1 so that the tape is driven at a constant speed of 5 mm/sec and the cylinder 1 is rotated at a constant speed of 2000 rpm. This cylinder 1
The ATF signal recorded on the tape is read by two rotating heads mounted on the top facing each other at 180 degrees, and the signal processing circuit 7 inputs the servo signal to the servo circuit 5 via the recording/reproducing circuit 6. , As a result, the servo circuit 5 becomes
To control the rotation speed of a cylinder 1 and to enable correct tracing of a track. Further, the signal processing circuit 7 performs recording/
The signal of the subcode area received from the reproduction circuit 6 is output to the subcode control circuit 8, and the subcode control circuit 8 which received this signal reproduces the subcode from this signal, detects the parity error, and The result is sent to the drive control circuit 9. Furthermore, the data read by both heads is transferred by the signal processing circuit 7 to the encoding/decoding circuit 12, where it performs error detection and correction according to the DAT format, and requests the memory control circuit 15 to transfer the data. . The memory control circuit 15 once transfers this data to the layered ECC circuit 13, and after the layered ECC circuit 13 performs error correction according to an error correction algorithm, the data is transferred to the memory 14 and stored. Then, the system control circuit 16 transfers the decoded data stored in the memory 14 to the host computer 20 and other DAT recorders via the interface control circuit 17 as necessary.

<Recording operation> In response to a data recording request,
The system control circuit 16 instructs the memory control circuit 15 to transfer data to the memory 14. The memory control circuit 15 that receives the data transfer request via the interface control circuit 17 receives the data and stores it in the memory 14. The system control circuit 16 instructs the memory control circuit 15 to transfer data to the layered ECC circuit 13, and encoding is performed according to the layered ECC format. This data is transferred to the encoding/decoding circuit 12, where it is encoded based on the DAT standard, and then transferred to the signal processing circuit 7. Then, the signal processing circuit 7 receives the subcode data from the subcode control circuit 8, switches the mode to recording mode, and records the data on the magnetic tape via the recording/reproducing circuit 6.

Next, the interface specifications of the DAT recorder of this embodiment will be explained. The DAT recorder used in this example has two interfaces with different specifications, one for connection with the host computer 20 and the other for connection with other DAT recorders (local interface 19). Yes, switching between these two interfaces is done by the interface control circuit 1.
7. As described above, the standard interface SCSI (SCSI circuit 18) is used as the interface for connecting the host computer 20. The local interface 19 also enables data transfer from one master device to multiple slave devices connected to it, enables one-to-many copying, and executes copying. While there,
It is provided for the purpose of opening an interface with the host computer 20 and allowing the host computer 20 to access other devices. This local interface 19 transfers data without handshaking (except for the CMND bit), and in addition to 8-bit parallel data, it can transfer 1-bit data called CMND at a time, and the transfer rate is approximately 1.5 Megabytes/second. Since handshaking is not used, a 512-byte FIFO (first-in-first-out) buffer memory is provided on the receiving side, and the CMND bit is also buffered in addition to data. However, since DMA (direct memory access) does not transfer CMND data to memory, CMND data is not transferred to memory.
A register is provided that indicates whether data of ND=1 has been read. Note that data transfer can be performed by either DMA or program I/O. There are a command transfer process and an information transfer process as processing processes of the local interface 19, and the CMND signal is used to distinguish between these two processes. The CMND bit is set to 1 in the first byte of command transfer, and the CMND bit is cleared to 0 when the first byte is received. The start and end of command transfer is determined by setting the CMND bit to 1 again when transferring the last byte of the command.

<Arbitration> Arbitration of the local bus (local interface 19) will be explained with reference to the timing chart of FIG. After confirming that the local bus connected to itself is not in use, when the self drive (self DAT recorder) issues a request to use the local bus (LBRQ: local bus request), the local bus BRQO (bus request output) is asserted. BRQO is connected to the signal line BRQI (bus request input) of the drive with the higher ID (identifier), and the higher drive can know that a local bus request has been issued from the lower drive. If the host drive does not issue a bus request at this time, use of the bus is permitted and the BG
TI (bus ground input) is asserted. When a device has the right to use the bus, the right to use the bus will not be transferred even if a lower drive requests to use the bus. However, if the own drive negates LBRQ and withdraws the bus use request, the BGTO (bus ground output) signal is asserted, and the right to use the bus can be transferred to the lower drive that has issued the bus request. Again, when the self-drive asserts LBRQ, BGTO is immediately negated and the right to use the bus can be recovered. The lower drive can recognize that it has lost the right to use the bus by negating the BGTI connected to the BGTO of the upper drive. If the host drive issues a bus usage request while the host drive has the right to use the bus, the BGTI of the host drive is negated and the bus usage right is transferred to the host drive. Furthermore, if a bus use request is canceled when no other drive has issued a bus use request, BRQO and BGTI are also negated, resulting in a bus free state. Note that FIG. 3 shows a logic circuit diagram of this bus arbiter.

Next, a method for selecting a DAT recorder will be explained. As shown in Figure 4, there are two host computers, and each host computer has multiple D
An example will be explained in which AT recorders are connected by SCSI and a plurality of DAT recorders are connected to the local interfaces of these DAT recorders. In the diagram, the DAT recorder is simply D
It is simply written as AT. 2 host computers #0
and #1, and DAT recorders #0 to #3 are connected by a SCSI bus, and host computers #0 and #1 can access any of the DAT recorders #0 to #3. Host computer #0 and #1
When both request access, arbitration occurs, and the host computer with the higher priority gets the right to use the bus. The host computer that has acquired the right to use the bus specifies which DAT recorder it will access. In response to the access request from the host computer, the selected DAT recorder prepares to receive the command, and when the preparation is completed, requests the host computer to transfer the command. Upon receiving the command, the DAT recorder analyzes the received command, performs command processing such as data recording and reproduction, tape operation, etc., and returns the execution results to the host computer as a status byte. After that, it sends a 1-byte message to the host computer informing it that the series of processing has been completed.

In the system of FIG. 4, DAT recorders #0 to #3 can be recognized from host computers #0 and #1, and identification symbols corresponding to each device are assigned. Here, DAT recorders #0 to #
3 is assigned as 0 to 3, respectively. Each DA
The T recorder checks the connection status of its own external interface and checks the DAT connected to the host computer.
The recorder is a DA connected to its own local bus.
Check the number of T recorders. In this embodiment, the confirmation method uses a method in which an ID that can be set using a dip switch provided in each DAT recorder is sequentially incremented from 0, the ID is sent out, and the number of devices is confirmed based on the response. In this way DAT recorder #
1 and #2 have 5 DAT recorders each.
AT recorder #3 can know that two DAT recorders are connected, and DAT recorders #1 to #
3 allocates an identification symbol to the DAT recorder connected to itself (slave DAT recorder serving as a slave device). That is, from the perspective of DAT recorder #1, D
AT recorders #2, #4 to #7 are assigned to slave units 1 to 5. Furthermore, from the perspective of DAT recorder #2, DAT recorders #1, #4 to #7 are assigned to slave units 1 to 5, and from the perspective of DAT recorder #3, DAT recorders #8 and #9 are assigned to slave units 1 to 2. Here, slave unit 0 represents the controller (master DAT recorder serving as a master device) itself. Therefore, for example, if the host computer
5, use slave unit 3 of DAT recorder #1.
Alternatively, by selecting slave unit 3 of DAT recorder #2, DAT recorder #5 can be indirectly selected. Then, the DAT recorder that receives commands from the host computer manages the slave device as a controller. One controller is always selected, and two or more controllers cannot act as controllers at the same time.

Now, by host computer #0,
When DAT recorder #1 is selected as a controller (master device), DAT recorder #1 sends a command to all DAT recorders connected to the local bus to become slave devices. A device designated as a slave device enables only the local interface of a device connected to the SCSI bus, such as DAT recorder #2, and disconnects the SCSI bus. By this process, collisions in command reception can be avoided even in devices such as DAT recorder #2 that may receive commands from both the SCSI bus and the local bus. Specifically, when operating a DAT recorder using SCSI commands, the device to be the controller is selected as the target ID. In the case of FIG. 4, DAT recorders #1 to #3 are selected, and for example, host computer #0 acquires the right to use the SCSI bus and the DAT recorders #1 to #3 are selected.
When T recorder #1 is selected, DAT recorder #1 is
Receive a CSI command. According to the SCSI standard, bits 0 to 2 of the second byte of a command can be used to specify a logical unit number. When a command is sent with the logical unit number set to 0, DAT recorder #1 performs processing according to the received command using the SCS.
Execute according to the sequence of I. Also, if 1 to 5 is specified as the logical unit number, DAT
Recorder #1 analyzes the received command, converts it into a local command, and sends it as a local command to the designated slave device using a protocol that meets the specifications of the local interface. The slave device that receives the local command performs processing according to the local command, and returns the execution result to DAT recorder #1 via the local bus. The above method allows the slave device to be selected from the host computer and controlled via the local interface.

Let us take as an example the case where the system shown in FIG. 4 is used to copy the contents of a magnetic tape set in DAT recorder #1 to a magnetic tape set in another device using a local interface. Explain the to-many copy operation.

[0021] The copy source device and the copy destination device are specified from the host computer using vendor-unique and supported SCSI commands for the DAT recorder. In this case, for example, specify DAT recorder #1 as the copy source device, and
Recorders #2, #4 to #7 can be designated as copy destination devices. At this time, a DAT recorder that has not been designated as a copy destination device ignores commands and data received via the local bus. For example, if DAT recorders #4 to #7, excluding DAT recorder #2, are designated as copy destination devices, DAT recorder #2 can be operated by the host computer using SCSI. The DAT recorder that receives the slave request local command inspects the magnetic tape set in each device to check whether it is an unrecorded tape. If the set tape is an unrecorded tape, the tape is rewound and positioned at the BOT (bottom of tape). Further, as a result of the inspection, for tapes on which data has already been recorded, positioning is performed on the BOT in the same way as for unrecorded tapes, but a message is sent to the copy source apparatus to inform the effect. Upon receiving the message, the copy source device sends a status requesting the host computer to confirm the tape set in the copy destination device that received the error response. After confirming the status received from the copy source device, the host computer sends a SCSI command to start copying when executing copying. DAT recorder #1, which received the copy start command, rewinds the tape set in its own device, then notifies the copy destination device that it will start copying, and transfers the data sequentially read from the beginning of the tape to the local bus. Send. The copy destination device receives data from the local bus and records it on tape. During recording, even if a write error occurs, the device does not retry and ends with an error. After sending the copy start command, the host computer is disconnected and can access DAT recorders not related to copying. The host computer can send commands to DAT recorder #1 using SCSI, and can obtain information such as the progress status of copying and the completion of copying.
You can also cancel copying. Furthermore, in this system, it is possible to copy data between slave devices that are not connected to a computer; for example, the copy source device can be DAT recorder #5, and the copy destination device can be DAT recorder #7. In that case, DAT recorder #1 (or DAT recorder #2) becomes the controller and controls by sending commands received from the host computer to DAT recorders #5 and #7 and receiving the status returned from each. .

FIG. 5 shows the data flow when tape copying is performed using the system of this embodiment. In the system of this embodiment, as shown in Fig. 1, the data after error correction by layered ECC is sent to the local bus, and in the data flow diagram of Fig. 5, the local bus is connected to the position (1). Become. The digital data reproduced by the recording/reproducing system and signal processing circuit of the copy source DAT recorder A is subjected to error correction by the encoding/decoding circuit, and the data after error correction by layered ECC is sent to the local bus. , used as data for copying. However, even if a local bus is provided in the same way as digital copying of audio, the error correction ability will be reduced, but copying in units of frames will be possible. In this case, the local bus will be connected at position (2) in the data flow diagram.

[0023] In the above-mentioned embodiment, an example was taken where the device was provided with two external buses with different specifications and a plurality of devices were connected via a local bus, but in the case of a device with two built-in drives. It is possible to operate both drives in a similar manner.

[0024]

As described above, according to the present invention, it is possible to operate a device that is not directly connected to a host computer via a local interface. In addition, by using a local interface with different specifications from the interface used to connect to the host computer, the host computer can control the bus even during processing that occupies the bus for a long time, such as copying magnetic tape. Internal processing and access to other devices can be performed independently of copy processing. Furthermore, with regard to devices connected by a local bus, the host computer could not recognize the existence of the device and could not be operated by the host computer. By providing the host computer with the ability to operate other devices using a local interface, and having the device recognize and manage the devices connected to the local bus, the host computer can control the devices indirectly connected via the local bus. Operation becomes possible. Furthermore, if two or more devices are connected to a host computer and those devices are connected via a local bus, the device that receives commands from the host computer becomes the controller, and is used to manage other devices. No malfunctions occur.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of a magnetic tape storage device according to an embodiment of the present invention.

FIG. 2 is a signal timing diagram showing a local interface bus arbitration method used in an embodiment of the present invention.

FIG. 3 is a logic diagram of a bus arbiter for implementing the arbitration shown in FIG. 2;

FIG. 4 is an explanatory diagram showing the operating environment of the magnetic tape storage device control system according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram showing the flow of data when a magnetic tape is copied using the magnetic tape storage device according to the embodiment of the present invention.

[Explanation of symbols]

1 Cylinder 2 Cylinder motor 3 Capstan motor 4 Reel motor 5 Servo circuit 6 Recording/playback circuit 7 Signal processing circuit 8 Subcode control circuit 9 Drive control circuit 10 Mechanical drive circuit 11 Loading motor 12 Encoding/decoding circuit 13 Layered ECC circuit 14 Memory 15 Memory control circuit 16 System control circuit 17 Interface control circuit 18 SCSI circuit 19 Local interface circuit 20 Host computer

Claims (5)

[Claims] 1. A magnetic tape storage device that operates as a computer storage device according to instructions from the computer and records/reproduces digital data on a magnetic tape, having two or more external connection interfaces,
Record/record data using respective interfaces
Equipped with a function to perform playback, a function to convert data received from the first interface and output it to the second interface, and a function to output the data received from the second interface to the first interface. A magnetic tape storage device characterized by: 2. One or more magnetic tape storage devices according to claim 1 are connected to one or more control devices by the first interface, and any of the magnetic tape storage devices are connected to the first interface. A magnetic tape storage device connected through a second interface and receiving a tape duplication instruction from the control device through the first interface selects a magnetic tape storage device connected through the second interface according to the instruction from the control device. A magnetic tape storage device control system characterized in that data transfer is performed independently of the first interface and tape copy operation is performed. 3. One or more magnetic tape storage devices according to claim 1 are connected to one or more control devices by the first interface, and one or more magnetic tape storage devices are connected to the control device by the first interface. The single or plurality of magnetic tape storage devices according to claim 1 are connected to any magnetic tape storage device according to claim 1 through only the second interface, and the magnetic tape storage device that receives tape duplication instructions from the control device through the first interface is The tape storage device is directed to the second
1. A magnetic tape storage device control system, characterized in that a magnetic tape storage device connected by a first interface is selected, data is transferred independently of the first interface, and a tape copy operation is performed. 4. The magnetic tape storage device according to claim 3, wherein the magnetic tape storage device receives a tape duplication instruction from the control device through the first interface, and a tape to be a duplication source is set in accordance with the instruction from the control device. A magnetic tape storage device and a magnetic tape storage device in which a duplication destination tape is set are selected, a tape duplication command is sent to the duplication source and duplication destination magnetic tape storage devices through the second interface, and the second interface 1. A magnetic tape storage device control system characterized in that a tape copy operation is performed by data transfer by . 5. According to claims 2 to 4, if an interrupt request is received from the first interface while data transfer is being performed using the second interface, the second interface The data transfer by the interface is temporarily interrupted, the data transfer is performed with the control device by the first interface, and after the data transfer by the first interface is finished, the data transfer by the second interface is resumed. A magnetic tape storage device control system characterized by: