JP2001297541A - Magnetic tape device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the destruction of important data by a medium defect by detecting the medium having a possibility of the medium defect and instructing the exchange of the medium. SOLUTION: This device has a drive control circuit 1 which performs I/O control to a drive 2, a timer 3 which measures the execution time of the write operation of the drive 2, a retry time storage circuit 4 which stores the retry time assigned from a host, a write operation time storage circuit 5 which stores the execution time of the measured write operation, a retry time comparison circuit 6 which compares the retry time and the write operation time, a number- of-retry times holding circuit 8 which holds the number of retry times from the retry time assigned from the host and the result obtained from the retry time comparison circuit 6, a numberof-retry times storage circuit 7 which stores the number of retry times assigned from the host and a number-of-retry times comparison circuit 9 which compares the number of retry times obtained from the number-of-retry times holding circuit 8 and the number of retry times assigned from the host.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape device, and more particularly to a magnetic tape device having a function of preventing data destruction due to a medium defect.

[0002]

2. Description of the Related Art Conventionally, a defect in a magnetic tape medium (hereinafter, referred to as a medium) in a magnetic tape device is detected only when an error occurs, and important data is destroyed by the occurrence of the error. was there.

One of the countermeasures is, for example, based on the number of retries (hereinafter referred to as “retry”) performed for a data error that has occurred when writing or reading data to or from a certain medium and the running distance. A technique is disclosed in which a retry rate for a traveling distance per book is calculated, an average value of retry rates of a plurality of media is calculated, and when the average value exceeds a preset threshold, the medium is cleaned. (Japanese Patent No. 298
0040).

[0004]

However, the above-described technique is a preferable method as a general preventive maintenance for reducing data errors caused by adhesion of dust and dirt, etc. In order to prevent this from happening, it is necessary to take more detailed measures.

The present invention has a function of counting the number of successful writes by retry, and by requesting a medium exchange for a medium having a large number of successful writes by retry, prevents data destruction due to a medium failure at retry over. It is an object of the present invention to provide a magnetic tape device having a function of preventing data destruction due to a medium defect.

[0006]

According to the present invention, a drive for writing / reading a medium, a drive control circuit for performing I / O control on the drive, and an execution time of a write operation of the drive are measured. A timer, a retry time storage circuit that stores a retry time specified from a higher order, a write operation time storage circuit that stores a write operation execution time measured by the timer, and a retry time obtained from the retry time storage circuit. A retry time comparison circuit that compares the write operation time obtained from the write operation time storage circuit; and a retry time specified from a higher order via the drive control circuit and the number of retries from the result obtained from the retry time comparison circuit. Retry count holding circuit to hold, and retry count table to store the retry count specified from the top A circuit, characterized in that it comprises a number of retries comparator circuit for comparing the number of retries specified from the host to obtain a retry count obtained from the retry count holding circuit from the retry count storage circuit.

The retry count holding circuit is characterized in that when the execution time of the write operation is longer than the retry time specified from the top, "+1" is added to the held retry count. When the number of retries held by the number of retries holding circuit is larger than the number of retries specified by the host, the retry number comparison circuit sends a request to the drive control circuit to replace the medium mounted on the drive. It is characterized by performing.

Subsequently, the present invention provides a method for writing /
Read drive and I / O to this drive
A drive control circuit that performs control, a timer that measures an execution time of a read operation of the drive, a retry time storage circuit that stores a retry time specified from a higher order,
A read operation time storage circuit for storing an execution time of the read operation measured by the timer; and a retry time comparison for comparing a retry time obtained from the retry time storage circuit with a read operation time obtained from the read operation time storage circuit. A retry count holding circuit for holding a retry count specified from a higher order via the drive control circuit and a result obtained from the retry time comparison circuit, and a retry for storing a retry count specified from a higher order. A retry count storage circuit, and a retry count comparison circuit that compares the retry count obtained from the retry count holding circuit with the retry count specified from the higher order obtained from the retry count storage circuit.

The retry count holding circuit is characterized in that when the execution time of the read operation is longer than the retry time specified from the top, "+1" is added to the held retry count. When the number of retries held by the number of retries holding circuit is larger than the number of retries specified by the host, the retry number comparison circuit sends a request to the drive control circuit to replace the medium mounted on the drive. It is characterized by performing.

[0010]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. Referring to FIG. 1, the magnetic tape device of the present invention writes / writes data on a loaded medium.
A drive 2 for reading (write / read), a drive control circuit 1 for performing I / O (input / output) control on the drive 2, a timer 3 for measuring the execution time of the write operation of the drive 2, A retry time storage circuit 4 for storing a designated retry time; a write operation time storage circuit 5 for storing the execution time of a write operation measured by the timer 3;
Retry time obtained from and write operation time storage circuit 5
A retry time comparing circuit 6 for comparing the write operation time obtained from the retry time, and a retry for holding the number of retries from the retry time specified from the higher order via the drive control circuit 1 and the result obtained from the retry time comparing circuit 6. A number-of-times holding circuit 8, a number-of-retries storage circuit 7 for storing the number of retries (retry) specified from the top, a number of retries obtained from the number-of-retries holding circuit 8, and a number It is configured to include a retry number comparison circuit 9 for comparing the specified retry number.

Here, the drive control circuit 1 controls the I / O of the drive 2 from the upper level, and specifies the retry time and the number of retries in the write operation for determining a medium failure from the upper level.

For example, when the case where the internal retry processing of the drive in the write operation takes 5 minutes or more occurs three or more times, if the medium is determined to be defective, the retry time is 5 minutes from the higher order and the retry time is 5 minutes. Specify 3 times. The retry time specified from the higher order is stored in the retry time storage circuit 4, and the number of retries specified from the higher order is stored in the retry number storage circuit 7.

When a write I / O to the drive 2 is issued from the host, the drive control circuit 1
The write operation is instructed to the drive 2 and the timer 3 is started, and the completion of the write operation in the drive 2 is waited. Then, upon receiving the write operation completion from the drive 2, the drive control circuit 1 stops the timer 3.

When the timer 3 receives the timer stop request from the drive control circuit 1, the timer 3 stores the execution time of the write operation of the drive 2 in the write operation time storage circuit 5. The write operation time storage circuit 5 stores the stored drive 2
The execution time of the write operation is notified to the retry time comparison circuit 6.

Upon receiving the execution time of the write operation from the write operation time storage circuit 5, the retry time comparison circuit 6
The retry time is compared with a higher retry time stored in the retry time storage circuit 4. As a result, if the execution time of the write operation is longer than the retry time, the retry time comparison circuit 6 notifies the retry count holding circuit 8 that the retry time of the write operation is over.

When the retry count holding circuit 8 receives from the retry time comparison circuit 6 a notification indicating that the retry time of the write operation has exceeded, the held retry count is incremented by "+1".
And requests the retry number comparison circuit 9 to compare the number of retries. When the retry count comparison circuit 9 receives the retry count comparison request from the retry count holding circuit 8, the retry count holding circuit 8 stores the retry count specified by the higher order stored in the retry count storage circuit 7. The number of retries is compared with the number of retries.

As a result, when the number of retries counted internally is larger than the number of retries specified from the higher order, the retry number comparison circuit 9 sets the drive control circuit 1
Is notified of the retry count over. Then, the drive control circuit 1 that has received the notification of the retry count over from the retry count comparison circuit 9 requests the medium exchange to the host.

Next, the processing operation of the magnetic tape device of the present invention thus configured will be described in detail. FIG.
5 is a flowchart showing a flow of a processing operation of the magnetic tape device of the present invention.

Referring to FIG. 2, first, a retry time storage circuit 4 and a retry number storage circuit 7 are previously stored in the retry time storage circuit 4 and the retry number storage circuit 7 as criteria for judging a medium defect specified from a higher order.
The retry time and the number of retries are stored. Here, the command for the drive control circuit 1 is sent from the host to the drive 2 to eject the medium (demount).
(S1), the drive control circuit instructs the retry count holding circuit to reset the held retry count.

The number of retries held when the medium is ejected from the drive is reset (S2), and the number of retries held is set to "0" at the time of the next medium loading, so that the medium is loaded into the drive after the medium is loaded. It is possible to count the number of retries over the retry time that has occurred before ejection, and monitor the retry time over for each medium.

Next, when the command to the drive control circuit 1 from the host is a write operation (S3), the drive control circuit 1 activates the timer 3 before executing the write operation to the drive 2 (S4), and writes to the drive. The operation is performed (S5). When the write operation in the drive 2 is completed, the drive control circuit 1 stops the timer 3 (S6). When the drive control circuit 1 stops the timer, the timer 3 notifies the write operation time storage circuit 5 of the time from start to stop. The write operation time measured by the timer 3 is compared with the retry time specified by the higher order in the retry time comparison circuit 6 (S7). As a result, when the write operation time exceeds the retry time (S8), the retry time comparison circuit 6
It instructs the retry count holding circuit 8 to count the number of retries. When the retry count holding circuit 8 is instructed to count the number of retries from the retry time comparison circuit 6, the retry count holding circuit 8 adds "+1" to the held retry count, and notifies the retry count comparison circuit 9 of this (S9). .

Upon receiving the notification of the number of retries from the retry number holding circuit 8, the retry number comparison circuit 9 stores the number of retries specified from the top stored in the retry number storage circuit 7 and the number of retries counted internally. Compare with As a result, if the number of retries counted internally is larger than the number of retries specified from the top (S10), the retry number comparison circuit 9 notifies the drive control circuit that the number of retries has been exceeded.

When the drive control circuit 1 is notified of the retry count over by the retry count comparison circuit 9, the drive control circuit 1 determines that the medium currently in use may be defective and replaces the medium (to another medium). Is performed (S11), and the medium is exchanged with the drive 2.

Next, another embodiment of the present invention will be described. The above-described embodiment measures the execution time of the write operation for the drive and compares the retry time with the retry time to detect a medium defect when the drive retry frequently occurs at the time of writing.
In this embodiment, the drive control circuit starts a timer when a read (read) system operation for the drive is started,
Stop the timer when the read operation for the drive is completed.

That is, the execution time during the read operation is measured. As a result, it is possible to detect a medium defect even when the drive frequently retries when reading the medium.

[0026]

As described above, according to the magnetic tape device of the present invention, the retry time and the number of retries for judging a medium defect are designated from the upper level, and the execution time of the write operation (or read operation) for the drive is specified. By measuring and comparing the retry time and the number of retries, a medium that succeeds in a write operation (or a read operation) due to drive retry, that is, a medium with a possibility of a medium failure is detected and notified. It is possible.

Further, by detecting a medium having a possibility of a medium failure and instructing the medium to be replaced (or copied to a new medium), it is possible to prevent destruction of important data due to the medium failure. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of a processing operation of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 drive control circuit 2 drive 3 timer 4 retry time storage circuit 5 write operation time storage circuit 6 retry time comparison circuit 7 retry count storage circuit 8 retry count holding circuit 9 retry count comparison circuit

Claims (6)

[Claims] 1. A drive for writing / reading (write / read) to / from a magnetic tape medium, a drive control circuit for performing I / O (input / output) control on the drive, and measuring an execution time of a write operation of the drive. Timer, a retry time storage circuit for storing a retry time specified from a higher order, a write operation time storage circuit for storing a write operation execution time measured by the timer, and a retry time obtained from the retry time storage circuit. And a retry time comparison circuit for comparing the write operation time obtained from the write operation time storage circuit with the retry time specified from the higher order via the drive control circuit and the number of retries from the result obtained from the retry time comparison circuit. The number of retries that holds the number of retries And a retry count comparing circuit for comparing the number of retries obtained from the retry count holding circuit with the number of retries specified from the higher order obtained from the retry count storing circuit. Magnetic tape device. 2. The retry count holding circuit according to claim 1, wherein when the execution time of the write operation is longer than a retry time specified from a higher level, the retry count holding circuit adds “+1” to the held retry count. The magnetic tape device according to claim 1. 3. A magnetic tape mounted on a drive for a drive control circuit when a retry count held by the retry count holding circuit is larger than a retry count specified from a higher order. 2. The magnetic tape device according to claim 1, wherein a request for replacing the medium is made. 4. A drive for writing / reading to / from a magnetic tape medium, a drive control circuit for performing I / O control on the drive, a timer for measuring an execution time of a read operation of the drive, and a timer designated from the host. A retry time storage circuit for storing a retry time; a read operation time storage circuit for storing a read operation execution time measured by the timer; a retry time obtained from the retry time storage circuit; A retry time comparison circuit that compares the read operation time with the read operation time, a retry number holding circuit that holds the number of retries from the retry time specified from the higher order via the drive control circuit and the result obtained from the retry time comparison circuit, A retry count storage circuit for storing a retry count specified from a higher order; A magnetic tape device comprising: a retry number comparison circuit that compares the number of retries obtained from the number-of-times holding circuit with the number of retries specified from the higher order obtained from the retry number storage circuit. 5. The retry count holding circuit adds "+1" to the held retry count when the execution time of the read operation is longer than the retry time specified from the top. The magnetic tape device according to claim 1. 6. A retry count comparison circuit, wherein when a retry count held by the retry count holding circuit is larger than a retry count specified from a higher order, a magnetic tape mounted on a drive with respect to a drive control circuit. 5. The magnetic tape device according to claim 4, wherein a request for replacing the medium is made.