JP2001209501A - Magnetic recording / reproducing device and information processing device - Google Patents

Abstract

(57) Abstract: The present invention relates to a magnetic recording / reproducing apparatus and an information processing apparatus, and is applied to, for example, a case where data is backed up by a computer, and is used for backing up the same contents to a plurality of magnetic tapes. And the time required for backup can be shortened. According to the present invention, a plurality of recording / playback units (8, 9) execute download processing simultaneously and in parallel, and simultaneously play back data in parallel and selectively upload.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus and an information processing apparatus, and can be applied, for example, when backing up data by a computer.
According to the present invention, a plurality of recording / reproducing units execute download processing simultaneously and in parallel, and simultaneously reproduce data in parallel and selectively upload the data to back up the same contents to a plurality of magnetic tapes. The operation in such a case is simplified, and the time required for backup can be reduced.

[0002]

2. Description of the Related Art Conventionally, in an information processing system for processing various kinds of information by a computer, various backup systems are used to prevent loss of valuable data.

That is, in this type of information processing system, an uninterruptible power supply is provided, so that even when a commercial power supply is interrupted, a hard disk drive crash or the like can be effectively avoided and data being processed is lost. It has been made so that there is no. In the hard disk device, a so-called mirror configuration including a plurality of hard disks is adopted, so that even if an abnormality occurs in any one of the hard disk devices, valuable data can be restored.

Further, in this type of information processing system, in addition to backup of data in operation, for example, data or the like recorded in a hard disk drive is periodically downloaded to a tape streamer, and thereby valuable data may be lost. Everything is done so that there is no such thing.

[0005] When data is backed up by a tape streamer as described above, for example, in a bank, a backup by the tape streamer is executed almost every day during the night when work is completed. Furthermore, since data at such banks is required to be as thorough as possible, the same content is downloaded to two magnetic tapes and these magnetic tapes are stored in different storage locations. For example, even if one of the storage locations is damaged by an earthquake or the like, backup can be performed using the magnetic tape of the remaining storage location.

[0006]

However, as described above, 2
When the same content is recorded on one magnetic tape and backed up, the same operation is repeated twice, which makes the operation of the conventional system complicated and the time required for the download time longer. Was.

[0007] Even if two magnetic tapes having the same contents are created as described above, in the event that data recorded on the magnetic tape is uploaded and backed up, only one of the magnetic tapes is used. The remaining one magnetic tape is wasted. In the tape streamer, to the extent that there is no practical problem,
Although the error rate is configured to be extremely low, it cannot be asserted that no error occurs in the data output to the host device.

The present invention has been made in view of the above points, and simplifies the operation for backing up the same contents on a plurality of magnetic tapes, and further reduces the time required for the backup. A reproduction device and an information processing device are proposed.

[0009]

According to a first aspect of the present invention, there is provided a magnetic recording / reproducing apparatus, comprising:
And the operation of the second recording / reproducing unit is controlled so that the data output from the host device is recorded in the first and second recording / reproducing units simultaneously and in parallel, and the data is simultaneously recorded in the first and second recording / reproducing units. The data is reproduced in parallel and selectively output to the host device.

According to a fourth aspect of the present invention, the present invention is applied to an information processing apparatus, wherein data is recorded on a magnetic tape by the first and second recording / reproducing units simultaneously and in parallel, and the first and second recording are performed. The reproducing unit reproduces the data simultaneously and in parallel and selectively processes the data.

According to the first aspect of the present invention, the operation of the first and second recording / reproducing units is controlled in accordance with the command output from the host device, and the data output from the host device is converted into the first and second data. The recording / reproducing unit simultaneously records data in parallel.
And by simultaneously reproducing data in the second recording / reproducing unit in parallel and selectively outputting the data to the host device, data can be recorded from the host device in parallel by at least two recording / reproducing units. Also, the recorded data can be reproduced and output to the host device, thereby simplifying the operation for backing up the same contents to a plurality of magnetic tapes, and further reducing the time required for the backup. .

According to the fourth aspect of the present invention, the data is recorded on the magnetic tape by the first and second recording / reproducing units simultaneously and in parallel, and is recorded by the first and second recording / reproducing units simultaneously and in parallel. By reproducing and selectively processing the data, the data can be recorded from the host device simultaneously and in parallel by at least two recording and reproducing units, and the recorded data can be reproduced and processed. Thus, the operation for backing up the same contents to a plurality of magnetic tapes can be simplified, and the time required for the backup can be reduced.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(1) Configuration of Embodiment FIG. 1 is a block diagram showing an information processing system according to an embodiment of the present invention. The information processing system 1 is installed in, for example, a bank or the like, and performs various kinds of tallying operations and the like on a host device 2
And the backup device 3 backs up the data relating to these tasks and the data resulting from the processing.

That is, the host device 2 uses the hard disk devices 4 and 5 having a mirror configuration to execute processing related to various tasks by the arithmetic processing unit 6. Further, during the night when various processes are completed, various data recorded on the hard disk devices 4 and 5 are sent to the backup device 3 via the interface (IF) 7, and the data in the hard disk devices 4 and 5 are downloaded. Conversely, when a serious abnormality occurs in the host device 2 and the data recorded in the hard disk devices 4 and 5 becomes difficult to recover, the data recorded in the backup device 3 is uploaded via the interface 7. Then, the uploaded data is processed to restore the contents of the hard disk devices 4 and 5.

In these backup processes, the arithmetic processing unit 6 sends commands for instructing data download, upload, etc. to the backup device 3 via the interface 7, and further sends the data to be downloaded. Further, the arithmetic processing unit 6 receives the status transmitted from the backup device 3 via the interface 7, and analyzes the status. The arithmetic processing unit 6 outputs a command, if necessary, based on the analysis result.
It retransmits the data and sends out various inquiries.

The interface 7 is, for example, a SCSI
(Small Computer System Interface).

The backup device 3 switches the operation in response to the command output from the host device 2 in this manner, and simultaneously downloads the data output from the host device 2 for download by the tape streamers 8 and 9. The data is recorded, and the data is simultaneously reproduced in parallel by the tape streamers 8 and 9 and selectively transmitted to the host device 2.

That is, in the backup device 3, the tape streamers 8 and 9 are backup devices that can be directly connected to the host device 2 by the SCSI interface to back up data in the host device 2. In response to the input command, the tape streamers 8 and 9 return the status, for example, busy or ready, to the host device to switch the operation, record the sequentially input data on the magnetic tape helically, and record the data on the magnetic tape. Play and output the data.

At this time, the tape streamers 8 and 9 divide the sequentially input data into predetermined block units, add an error correction code in a product code format, and record with interleaving between tracks and interleaving between words. In addition, when the read-after-write process is executed and the data cannot be correctly recorded, the host device is notified. Further, the tape streamers 8 and 9 execute a retry process according to an instruction from the host device based on the notification. On the other hand, during playback, the tape streamers 8 and 9
Performs error correction processing using an error correction code added at the time of recording and outputs data. When an error that is difficult to correct further occurs, the tape streamers 8 and 9 notify the host device and execute a retry process according to an instruction from the host device.

If the tape streamers 8, 9 are not yet ready for the processing corresponding to the command, a busy status is sent out, whereas the preparation for the processing corresponding to the command is completed. Is executed, the status of Ready is sent. On the other hand, if an error occurs in the reproduced data, if an error is detected during read-after-write, or if an error such as a failure occurs, the status of the check condition (Check Condition) is returned and the host device is returned. Request Sens from
For e), report the status such as failure.

Thus, in this embodiment,
The tape streamers 8 and 9 are connected to the duplexing unit 10 by a SCSI interface, switch the operation according to a command sent from the duplexing unit 10, record the data sent from the duplexing unit 10 on a magnetic tape,
The data reproduced from the magnetic tape is sent to the duplex unit 10. Along with this series of processing, a corresponding status or the like is sent to the duplexing unit 10.

The duplexer 10 has an interface (I
F), is connected to the host device 2 by a SCSI interface via the interface 12, and is connected to the host device 2 via an interface (IF) 13 of a different system from the interface 12.
It is connected to the tape streamers 8 and 9 by the CSI interface. With these interfaces, the duplication unit 10 allows commands output from the host device 2,
The data is output to the tape streamers 8 and 9, and the status and data according to this command are sent to the host device 2. As a result, the duplexing unit 10 is connected to the tape streamer 8.
The download data is recorded simultaneously and in parallel at 9 and 9.
The tape streamers 8 and 9 reproduce the uploaded data simultaneously and in parallel, and selectively output the reproduced data to the host device 2. Thus, in the information processing system 1, the same contents can be downloaded to two magnetic tapes by a simple operation and in a short time.

In this process, the duplexing unit 10 temporarily stores the command, status, and data in the memory 14,
These commands, statuses, and data are transmitted under the control of the central processing unit (CPU) 15, thereby simplifying the control by the host device 2 and improving the reliability of the data to be uploaded.

FIGS. 2 and 3 show this central processing unit 1.
9 is a flowchart showing a processing procedure in the fifth embodiment. The backup device 3 executes this processing procedure when the backup by two tape streamers 8 and 9 is instructed by the operator's instruction in the host device 2, and the backup by only one tape streamer is instructed. In such a case, data is simply input / output between the tape streamer and the host device.

In this processing procedure, when a command is input from the host device 2, the central processing unit 15 proceeds from step SP1 to step SP2 and receives this command. In the case of downloading, the central processing unit 15 receives data to be downloaded following this command.

Subsequently, the central processing unit 15 proceeds to step SP3, and sends the received command and data to each of the tape streamers 8 and 9. As a result, in the information processing system 1, the command, as if the backup was performed by one tape streamer as viewed from the host device 2,
The data is transmitted and can be backed up by two magnetic tapes.

Subsequently, the central processing unit 15 proceeds to step SP4, and receives from the tape streamers 8, 9 the status for the command thus sent out. Here, at step SP3, the tape streamer 8,
If the command sent to 9 is a command for instructing upload and the tape streamers 8 and 9 are ready for upload, the central processing unit 15 reproduces the status following the status in step SP4. The received data will be received.

Subsequently, the central processing unit 15 proceeds to step SP5, where it determines whether the status and data received from the tape streamers 8 and 9 match. If the two tape streamers 8 and 9 are not yet ready for processing, a busy status is returned. In this case, the central processing unit 1
5 can obtain a positive result. When the preparation is completed by the tape streamers 8 and 9, the status of the ready is returned, so that a positive result can be obtained also in this case. When the status of the ready is returned as described above and the command sent to the tape streamers 8 and 9 is a command for instructing upload, the data normally received after the status also matches. You can get a positive result. Further, although very rarely, the status of the check condition is obtained even when both the tape streamers 8 and 9 have an abnormality, so that the central processing unit 15 can obtain a positive result also in this case.

When a positive result is obtained in step SP5, the central processing unit 15 proceeds to step SP6, where the status and data sent from the tape streamer 8 or 9 are sent to the host device 2. Then, the process proceeds to step SP7 to end the processing procedure.

Thus, in the information processing system 1, for example, when a busy status is sent to the host device 2, commands and data can be retransmitted from the host device 2 and the subsequent processing can be executed. When the status of the ready is returned, the data of the hard disk devices 4 and 5 can be sequentially downloaded and backed up at the time of recording, and the desired data can be downloaded from the tape streamer 8 or 9 at the time of reproduction. Can be uploaded.

On the other hand, if only one of the tape streamers 8 or 9 is busy, ready, or check condition, or if any bit of the reproduced data is different, the central processing unit 15 When a negative result is obtained in step SP5, the process moves from step SP5 to step SP8.

Here, the central processing unit 15 determines whether one of the tape streamers 8, 9 is busy. If a positive result is obtained here, the central processing unit 15 proceeds to step SP9, and retransmits the command and the data to the tape streamer that has transmitted this busy. In the following step SP10, status and data are received from the tape streamer, and the process returns to step SP5. Accordingly, if the status of one of the tape streamers 8 and 9 is different due to the busy status of one of the tape streamers, the central processing unit 15 repeats step S until the tape streamer is ready for processing and executes a command.
The processing procedure of P5-SP8-SP9-SP10-SP5 is repeated.

On the other hand, if a negative result is obtained in step SP8, the central processing unit 15 proceeds to step SP11 (FIG. 3). Here, the central processing unit 15
Determines whether the status returned from one of the tape streamers is a check command or not, and determines whether the tape streamers 8 and 9
It is determined whether or not the state is different.

If an affirmative result is obtained here, the central processing unit 15 proceeds to step SP12, where the abnormality of the tape streamer that has returned the check command is due to a failure, and the command is a reproduction command indicating upload. It is determined whether or not. Central processing unit 1
In this case, the tape streamer 5 sends a request sense command to the corresponding tape streamer, and determines from the response from the tape streamer whether the abnormality of the tape streamer that returned the check command is due to a failure. .

If a positive result is obtained here, the central processing unit 15 proceeds from step SP12 to step SP13.
And sends the status and data received from the normal tape streamer to the host device 2, and then returns to step SP7. As a result, in the information processing system 1, even if one of the tape streamers fails, the upload process can be executed by the data reproduced from the remaining normal tape streamer, and the abnormality of the host device 2 can be promptly corrected accordingly. It can be repaired.

On the other hand, if a negative result is obtained in step SP12, the abnormality of one of the tape streamers is due to a failure, and the command is a recording command instructing upload, or the one of the tape streamers is The abnormality is caused by a bit error, and the command is a reproduction command instructing download. Of these cases, for example, bit errors due to read-after-write and bit errors during playback can be repaired by retry, but if, for example, an error in the tape streamer is caused by a failure, it is necessary to start maintenance immediately. Become.

When a negative result is obtained in step SP12, the central processing unit 15 proceeds to step SP1.
Then, the process proceeds to step SP7, where the status of the check condition indicating the abnormality is transmitted to the host device 2, and then the process proceeds to step SP7 to end the processing procedure.

Thus, in this information processing system 1,
By issuing a request sense command from the host device 2 as necessary and inquiring about the status, for example, backup by one tape streamer, etc.
Necessary countermeasures have been implemented.

Thus, the central processing unit 15
When the status of the check condition is returned from the tape streamer 8 or 9 and the status of the check condition is transmitted to the host device 2 in step SP14, when the request sense command is input from the host device 2, the check condition is output. This command is selectively sent to the tape streamer that returns the status of. Further, the response by this command is transmitted to the host device 2.
To return. Further, the central processing unit 15 executes a retry process by sending a command input from the host device 2 to the tape streamers 8 and 9 in response to the response.

In a tape streamer, although data can be reproduced with extremely high reliability, it cannot be guaranteed that no bit error will occur, and a bit error will occur with a very small probability.
In this case, the tape streamers 8 and 9 cannot detect an error during reproduction, and the reproduced data is input to the duplex unit 10 as normal. In this case, the central processing unit 15 obtains a negative result in step SP5 by comparing the reproduced data, moves from step SP8 to step SP11, and further obtains a negative result in step SP11.

When a negative result is obtained in step SP11 in this way, the central processing unit 15 proceeds to step S11.
The process proceeds to P16, where the status of the check condition is returned to the host device 2, and the transmission of the reproduced data is stopped. Then, the process proceeds to step SP7 to end the processing procedure.

When a negative result is obtained in step SP15 and the status of the check condition is returned to the host device 2, the central processing unit 15 receives a request sense command from the host device 2, The “error due to data difference” is notified to the host device 2. Thereby, in the information processing system 1, when the backup is performed simultaneously and in parallel by the two tape streamers 8, 9, the two tape streamers 8, 9
By effectively utilizing the data backed up in step 9, the reliability can be remarkably improved as compared with the related art.

(2) Operation of the Embodiment In the above configuration, in the information processing system 1 (FIG. 1), various types of tallying processing are executed in the arithmetic processing unit 6 of the host device 2, and data and processing to be performed for this processing are performed. The resulting data is recorded on the hard disk drives 4 and 5 having a mirror configuration. Thereby, for example, the hard disk drive 4 or 5
In the event of a crash, for example, the hard disk device 4 or 5 can be replaced to recover valuable data from the data recorded on the other hard disk device.

Further, in the information processing system 1, data recorded on the hard disk devices 4 and 5 is sequentially sent to the backup device 3 and backed up during the night when the business is completed, thereby making it difficult for the host device 2 to recover the data. Even in the event that the data has been restored, the data can be restored using the backed up data.

In the backup processing, if the backup by one tape streamer 8 or 9 is selected by the operator, the information processing system 1
The tape streamer selected by the operator and the host device 2 communicate with each other via the duplex unit 10 via commands, status,
Data can be transmitted and received, so that data recorded on the hard disk drives 4 and 5 can be downloaded to a magnetic tape in the same manner as in a normal tape streamer backup.

On the other hand, if the backup by two tape streamers 8 and 9 is selected by the operator, the information processing system 1
5 are sequentially sent to the backup device 3, and the tape streamers 8 and 9 record the data simultaneously and in parallel. As a result, in the information processing system 1, the same contents can be recorded on two magnetic tapes in one backup, so that the operation by the operator can be simplified accordingly, and the time required for the backup can be reduced. It is possible to do.

In this process, in the information processing system 1, when a download command is sent from the host device 2, this command is sent from the duplexing unit 10 to the tape streamers 8, 9, and the status of the response by this command is duplicated. Returned to unit 10. Information processing system 1
Then, the tape streamers 8 and 9 are
From the status, both ready, busy,
In the case of a check condition, these statuses are returned to the host device 2.

When one of the tape streamers is busy, the command is resent from the duplexer 10 to this tape streamer. When both are ready, the status is returned to the host device 2. If one tape streamer is abnormal due to a check condition, the abnormality is notified to the host device 2. When a request sense command is input from the host device 2 due to the check condition, the duplex unit 10 sends a request sense command to the tape streamer that has returned the check condition, and The returned data is sent to the host device 2. Thereby, in the information processing system 1, the host device 2
The abnormality of the backup device 3 is specifically grasped by the
Corresponding processing such as maintenance can be executed as needed.

Further, the data to be downloaded following this command is sent to the tape streamers 8 and 9 by the duplication unit 10 and
The status of the response due to the transmission of this data is
Returned to 0. Here this status is ready,
In the case of a busy or check condition, these statuses are returned to the host device 2. On the other hand, when one of the tape streamers is busy, the command is resent from the duplexing unit 10 to this tape streamer. The status is returned to the host device 2.

When one of the tape streamers is abnormal due to a check condition, the abnormality is notified to the host device 2. When a request sense command is input from the host device 2 according to the check condition,
The duplexing unit 10 sends a request sense command to the tape streamer that has returned the check condition. Further, data returned in response to the request sense command is sent to the host device 2, whereby in the information processing system 1, the abnormality of the backup device 3 is specifically grasped by the host device 2, and maintenance and the like are performed as necessary. Can be executed. In this case, in this case, read-after-write processing is executed by the tape streamers 8 and 9,
Since an error may be detected by this processing, the information processing system 1 records data of the host device 2 on a magnetic tape by repeating retry as necessary, and furthermore, identifies a location where the error occurs at this time. The data of the avoidance host device 2 can be recorded. Also, at the discretion of the operator, it is also possible to download with only one tape streamer.

In this way, the host device 2
Is output from the duplexer 10 to the two tape streamers 8 and 9, and the duplexer 10 determines the status sent from the two tape streamers 8 and 9 and returns the status to the host device 2. As a result, regarding the data download, desired data can be downloaded in the host device 2 in the same manner as when downloading with one tape streamer, thereby simplifying the processing in the host device 2. Can be.

On the other hand, when an abnormality occurs in the host device 2 and it is difficult to recover the data only by the host device 2, the data recorded in the backup device 3 is uploaded to the host device 2 in the information processing system 1. This restores valuable data.

At this time, when an upload is instructed by one tape streamer 8 or 9 by the operator, in the information processing system 1, the tape streamer selected by the operator and the host device 2 are commanded via the duplex unit 10 via the duplex unit 10. The status and the data are transmitted and received, whereby the data recorded on the magnetic tape is reproduced by one tape streamer 8 or 9 and uploaded to the host device 2 in the same manner as the normal tape streamer upload.

On the other hand, when the upload by two tape streamers 8 and 9 is selected by the operator, in the information processing system 1, the tape streamers 8 and 9 are used.
Thus, the data recorded on the magnetic tape is reproduced, and the data is selectively uploaded to the host device 2.

In this processing, in the information processing system 1, when an upload command is sent from the host device 2, this command is sent from the duplexer 10 to the tape streamers 8, 9 in the same manner as at the time of download. The status of the response is determined by the duplexing unit 10, and if both are ready, busy, or check condition, these statuses are returned to the host device 2.
If either one of the tape streamers is busy, the command is resent from the duplexer 10 to this tape streamer, and when both become ready, this status is returned to the host device 2.

As a result, in the case of a ready, data is reproduced simultaneously and in parallel by the tape streamers 8 and 9, and this data is selectively sent to the host device 2 and uploaded. The host device 2 can resend the command as needed to obtain a ready status, and similarly, the data reproduced by the tape streamers 8 and 9 can be uploaded to the host device 2.

On the other hand, in the case of a check condition, the status can be confirmed from the host device 2 and necessary processing can be executed to cope with the case of uploading by one tape streamer.

When data is uploaded in this manner, in the information processing system 1, the reproduced data is compared in the duplexing unit 10, and if a difference is found in the bits, the data is uploaded to the host device 2. Aborted. This makes it possible to stop uploading bit-error data in extremely rare cases, such as when a bit error occurs in the reproduced data even if no error is detected in the reproduced data depending on the error correction processing. it can. As a result, in the information processing system 1, the reliability of data can be remarkably improved as compared with the related art by effectively utilizing the two recording and reproducing systems.

In this case, in the information processing system 1, the status of the check check condition indicating an abnormality is returned to the host device 2, and it is determined that a bit difference has occurred due to a request sense command from the host device 2. 2 and the host device 2 instructs a retry by this notification,
It is possible to reproduce correct data.

On the other hand, unlike at the time of recording, if one tape streamer is abnormal due to the check condition, in the information processing system 1, a request sense command is sent from the duplexer 10 to the corresponding tape streamer. From this response, it is determined whether or not the abnormality of the tape streamer is due to a failure. Here, if the abnormality is caused by a failure, it is considered that it takes time to repair the failure. In this case, the information processing system 1 operates in the same manner as when the upload by one tape streamer is selected by the operator. The magnetic tape is reproduced by the remaining one normal tape streamer, and the data from this tape streamer is transferred to the host device 2.
Will be uploaded to. Thereby, the information processing system 1
In the above, data can be uploaded even when one tape streamer breaks down by effectively utilizing the recording / reproducing system of the two systems, and the system can be recovered earlier by that much.

(3) Effects of the Embodiment According to the above configuration, two tape streamers execute download processing simultaneously and in parallel, and the two tape streamers simultaneously reproduce data in parallel. By selectively uploading, the operation of backing up the same contents to a plurality of magnetic tapes can be simplified, and the time required for the backup can be reduced.

The host device 2 sends the command sent from the host device to the two tape streamers and sends the status to the host device based on the status determination result.
The backup can be performed by a simple process as if the backup was performed by a tape streamer, and the processing in the host device can be simplified accordingly.

The data output from the two tape streamers is compared, and the output of the data to the host device is stopped based on the comparison result. As a result, desired data can be backed up with much higher reliability.

(4) Other Embodiments In the above-described embodiment, a case has been described in which the host device and the backup device are connected by the SCSI interface, and the duplexer and the tape streamer are connected. The invention is not limited to this, and various interfaces can be widely applied as needed.

In the above-described embodiment, the case has been described in which the host and the tape streamer form an interface by separate systems. However, the present invention is not limited to this, and a practically sufficient data transfer rate is secured. If the host device can reliably identify the external device from other external devices, a common interface may be used.

Further, in the above embodiment, the case where the backup device is constituted by two tape streamers has been described. However, the present invention is not limited to this, and the case where the backup device is constituted by three or more tape streamers. Can also be widely applied.

[0068]

As described above, according to the present invention, a plurality of recording / reproducing units execute download processing simultaneously and in parallel, and simultaneously reproduce and selectively upload data by simultaneously reproducing data. Operation when backing up the same contents to multiple magnetic tapes is simplified,
Further, the time required for backup can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an information processing system according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a processing procedure of a central processing unit of the information processing system of FIG. 1;

FIG. 3 is a flowchart showing a processing procedure subsequent to FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Information processing system, 2 ... Host device, 3 ... Backup device, 4, 5 ... Hard disk device, 8,
9 Tape streamer 10 Duplex

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B065 BA07 CA11 CC08 EA35 5D044 AB02 BC01 CC01 DE63 DE72 DE94 HL02 5D066 BA02 BA07 BA08 5D101 AC11 JA02 JA15

Claims (5)

[Claims] 1. A magnetic recording / reproducing apparatus for inputting / outputting desired data to / from a host device in accordance with a command output from a host device, wherein the data is recorded on a magnetic tape, respectively. First and second recording / reproducing units for reproducing the data recorded on the host device; controlling the operations of the first and second recording / reproducing units in accordance with the command; A control unit that records data in the first and second recording and reproducing units simultaneously and in parallel, reproduces data in the first and second recording and reproducing units in parallel and selectively outputs the data to the host device; A magnetic recording / reproducing apparatus comprising: 2. The control section controls operations of the first and second recording and reproducing sections by transmitting a command transmitted from the host apparatus to the first and second recording and reproducing sections. The first and second recording / reproducing units transmit a status in response to a command from the control unit, and the control unit determines the status output from the first and second recording / reproducing units 2. The magnetic recording / reproducing apparatus according to claim 1, wherein a status is transmitted to the host device. 3. The control unit according to claim 2, wherein the control unit compares data output from the first and second recording / reproducing units, and stops outputting data to the host device based on a result of the comparison. 3. The magnetic recording / reproducing apparatus according to claim 2, wherein: 4. An information processing apparatus for processing desired data, wherein said data is recorded on a magnetic tape by a first and second recording / reproducing unit simultaneously and in parallel, respectively, and said first and second recordings are performed. An information processing apparatus wherein a reproducing unit reproduces data in parallel and selectively processes the data. 5. The data output from the first and second recording / reproducing units are compared, and data reproduced by the first and second recording / reproducing units is selected based on the comparison result. The information processing apparatus according to claim 1.