JPH01122073A - Control system for magnetic disk device - Google Patents

Abstract

PURPOSE:To reduce the number of times by retrial and to improve a processing effect by storing previously trail history at every record of a magnetic disk device and referring to the trial history at the beginning of a read operation and performing the read operation by an abbreviated procedure when the retrial is performed. CONSTITUTION:The addresses 11 at every cylinder, every head and every record are stored previously as storage contents 12 in the storage circuit of the magnetic disk device. By considering the contents of the storage contents 12 as the trail history, the storage contents 12 are specified by one address 11. Besides, the storage contents 12 are classified into normal finish by reread (a), normality by reread after offset seek (b), normal finish by ECC correction (c), abnormal finish (d) and number of times of retrial (e). Then, at the beginning of the read operation, the storage contents are referred to, and when the retrial is performed, the read operation is performed by the abbreviated procedure so that the number of times of the retrial is reduced and the processing effect is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control method for a magnetic disk device, and particularly to a control method for a magnetic disk device when reading data from the magnetic disk device.

[Conventional technology]

Conventionally, when reading an arbitrary record from a magnetic disk device, the procedure is as shown in FIG. That is, data is read from the target record (reference numeral 51), and it is determined whether the read operation has been completed normally or not (reference numeral 52). If the read operation has not been completed normally, the data is read again and the offset command is used. The re-reading operation after the offset seek and the correction operation using the ECC are retried (reference numeral 53), and if they do not end normally, the above-mentioned operation is repeated a prescribed number of times (reference numerals 54 and 55); Note that if the operation is not normal, the process ends (reference numeral 56), and if the operation is normal during the above-mentioned operation, it ends normally (reference numerals 57 and 58).

[Problem that the invention seeks to solve]

The conventional control method for magnetic disk devices as described above is
When attempting to read data again from a record for which a data read operation was previously performed and completed normally after a retry, there is no history of past retries, so the procedure shown in Figure 3 is repeated. The read operation must be performed using the same procedure. Therefore, since the read operation is performed from the first step, there is a drawback that the number of retries increases.

[Means for solving problems]

The magnetic disk device control method of the present invention stores a trial history of data reading operations from the magnetic disk device in a storage circuit for each cylinder, each head, and each record, and when performing the data reading operation again. , the reading operation is performed by a shortened procedure with reference to the trial history stored in the storage circuit.

That is, the magnetic disk device control method of the present invention stores a trial history of data reading operations from all records of the magnetic disk device in a storage circuit for each record of each head of each cylinder. When reading data from the magnetic disk device by referring to the trial history stored in the circuit, if it is found from the contents that a retry is being performed, the read operation is performed using a shortened procedure. The method includes updating the trial history of the memory circuit.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a flowchart showing one embodiment of the present invention, and FIG.
The figure is an explanatory diagram showing the contents of the trial history stored in the memory circuit in the embodiment of FIG. 1.

As shown in FIG. 2, the storage circuit has an address 11 for each record for each head for each cylinder of the magnetic disk device.
In the area of the memory circuit specified by one address 11, the memory contents 12 of trial H and FM include normal completion by rereading (a) and normal completion by rereading after offset seek. (b), normal termination due to FCC correction (C), abnormal termination (d), and number of retries (e) are stored.

As shown in the flowchart in Figure 1, this control method:
First, the address of the cylinder, head, and record of the magnetic disk device from which data is to be read is specified, and the trial history stored therein is read from the area of the storage circuit corresponding to the address (reference numeral 1). If it is found from the content of the trial history that no retry has been performed (reference numerals 2 and 3), a normal read operation is performed (reference numeral 4).
If it ends normally (reference numeral 5), the trial history is updated and it ends normally (reference numerals 11 and 10), and if it does not end normally, proceed to retry (reference numeral 6).Retry from the contents of the trial history. If it is found that the process has been performed (reference numeral 2), perform the read operation when the process ends normally by retrying (reference numeral 6), and update the trial history when it ends normally (reference numeral 7). Reference number 1
2 and 10). If the process does not end normally, proceed to reference numeral 6) for retrying. Successful completion on retry (reference number 7)
) or retry a predetermined number of times (8), update the history (10), and end the process.

〔Effect of the invention〕

As explained above, the magnetic disk device control method of the present invention stores a trial history for each record, refers to the trial history at the beginning of a read operation, and if a retry is performed, By performing a read operation using a shortened procedure, the number of retries can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing one embodiment of the present invention, and FIG.
1 is an explanatory diagram showing the contents of the trial history stored in the embodiment of FIG. 1, and FIG. 3 is a flowchart showing an example of a conventional control method for a magnetic disk device. 11... Address, 12... Memory contents.

Claims (1)

[Claims] A trial history of data reading operations from all records of the magnetic disk device is stored in a storage circuit for each record of each head of each cylinder, and the trial history stored in the storage circuit is referred to. When performing a data read operation from the magnetic disk device, if it is found from the contents that a retry is being performed, the read operation is performed using a shortened procedure to update the trial history of the storage circuit. A control method for a magnetic disk device characterized by: