JPH0283864A - Magnetic disk processor - Google Patents

Abstract

PURPOSE:To improve reliability by considering that a searching action becomes normal only when first reading data and re-reading data are made coincident with each other when a reading error occurs, when the data reading error of a counting part is detected and a searching action is re-tried. CONSTITUTION:When the positioning to an aimed counting part is completed, data is read and stored to a data storing circuit 22 and a reading error detecting correcting circuit 23 checks whether or not the reading error occurs. When the error occurs, it is investigated whether or not this can be corrected, and if possible, correction is executed, the corrected data and the expected data are compared, and when they are coincident, the re-positioning is executed for the aimed counting part and the re-reading data is stored to a data storing circuit 24. Simultaneously, the re-reading checks whether or not the error occurs again, and when it occurs, they are compared by a comparator 27, when they are coincident, it is considered that the searching action is normally completed and the processing is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk processing device, and particularly to a magnetic disk processing device that retries a search operation by detecting a data reading error in a counting section.

[Conventional technology]

Conventionally, in this type of magnetic disk processing device, when a correctable read error occurs in a count section, as shown in the processing flowchart of the search operation in FIG. Data is read and discarded, and the normality of the search operation is checked by checking whether the corrected data matches the expected data.

[Problem to be solved by the invention]

In the above-mentioned conventional magnetic disk processing device, if the repositioning to the target count section is incorrect, the repositioning involves reading and discarding the data of the subsequent count section. It has the disadvantage that it is treated as a counting part.

[Means to solve the problem]

When the magnetic disk processing device of the present invention searches for a count section written on a magnetic disk based on the read start address and read data length given from the host processor, the magnetic disk processing device searches for the count section written on the magnetic disk based on the read start address and read data length given by the host processor. In a magnetic disk processing device, when a correctable error occurs in the read data, the search operation ends normally if the corrected data matches the expected data generated in advance. When it is determined that the read data matches the expected data, the reread data storage means stores the reread data read after repositioning to the target count section, and the reread data storage means detects that an error has occurred in the reread data. a first comparison circuit that compares the read data and the re-read data and determines that the search operation has ended normally when a match is found; and a second comparison circuit which determines that the search operation has ended normally when a match is found by comparing the search data with the expected data.

〔Example〕

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

FIG. 1 is a block diagram of an embodiment of the present invention, showing a magnetic disk processing device 2, a related host processor 1, and a magnetic disk unit W3. The magnetic disk processing device 2 includes a conventionally provided microprocessor 20 that converts the read start address and read data length given from the host processor 1 to match the magnetic disk device 3, and a microprocessor 20 that converts the read start address and read data length given from the host processor 1 to match the magnetic disk device 3. a reading circuit 21 for reading data in the count section and data section;
a read data storage circuit 22 that stores read data read by a read data storage circuit 22, a read error detection and correction circuit 23 that detects read errors in the read data and generates correction information, and a count section output from a microprocessor. an expected data storage circuit 25 that stores data;
Corrected data storage circuit 26 which reads read data and correction information by microprocessor 20 and stores the corrected data when a correctable error occurs.
and a fourth comparison circuit 30 that compares the read data with expected data when no error is detected in the read data, and a third comparison circuit that compares the corrected data with the expected data. In addition to the circuit 29, the invention provides a reread data storage circuit 24 for storing reread data when a correctable read error occurs in the counting section, and a reread data storage circuit 24 for comparing said read data with the reread data. One comparison circuit 27 and a second comparison circuit 28 for comparing the reread data and expected data are provided.

FIG. 3 is a flowchart of the processing of the embodiment shown in FIG. 1, and the search operation of the counting section in FIG. 1 will be explained below with reference to FIG. First, positioning is carried out to the target count part (Step ■), and when the positioning is completed, the data of the count part is read and stored in the read data storage circuit 22 (Step ■), and at the same time, the data is read by the read error detection and correction circuit 23. Check whether a reading error has occurred (step ■). If a reading error occurs here, perform the error correction operation (step ■) and check whether it can be corrected (step ■)
. If the correction is possible, the corrected data is compared with the expected data by the third comparison circuit 29 (Step 2), and if they match, the count section is repositioned to the target count section (Step 2). The data is re-read and stored in the re-read data storage circuit 24 (step 2). At the same time, check whether a reading error has occurred in this re-reading (Step 2). If a reading error has occurred, the first comparing circuit 27 compares the read data with the re-read data. (Step [phase]) If they match, the search operation is terminated normally. On the other hand, if no reading error has occurred in step (2), the fourth comparison circuit 30 compares the read data with the expected data (step (2)), and if they match, the search operation is terminated normally. , if they do not match, the search operation ends abnormally. In addition, if correction is not possible in step ■, if the corrected data and expected data do not match in step ■, and if read data and reread data do not match in step [phase], the search operation is performed. Ends abnormally.

Furthermore, if no error is detected in the re-reading in step (2), the second comparison circuit 28 compares the re-read data with the expected data (step @), and if a match is found, the search operation is considered to have ended normally. If a mismatch is found, the search operation is terminated abnormally.6 [Effects of the Invention] As explained above, the present invention allows the repositioning of the count section to match the first read data when a reading error occurs during subsequent rereading. The search operation is considered to have ended normally only when the data matches the reread data, and if no reading error occurs during rereading,
By determining that the search operation has completed successfully only when the reread data and the expected data match, positioning allows the data section to be read even if an error occurs in repositioning to the target count section. This has the effect of providing a highly reliable magnetic disk processing device that does not make mistakes.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a flowchart of a search operation in a conventional magnetic disk processing device, and FIG. 3 is a flowchart of a search operation in the embodiment of FIG. DESCRIPTION OF SYMBOLS 1... Host processor, 2... Magnetic disk processing device, 3... Magnetic disk device, 20... Microprocessor, 21... Reading circuit, 22... Read data storage circuit, 23... Reading error detection and correction circuit, 2
4... Reread data storage circuit, 25... Expected data storage circuit, 26... Corrected data storage circuit, 27.
...first comparison circuit, 28...second comparison circuit, two...third comparison circuit, 30...fourth comparison circuit.

Claims (1)

[Claims] When searching for the count section written on the magnetic disk from the read start address and read data length given by the host processor, read the data of this count section after positioning to the target count section,
When a correctable error occurs in the read data, the search operation is normally completed if the corrected data matches the expected data generated in advance. re-read data storage means for storing re-read data read after re-positioning to the target count section when an error has occurred in the re-read data; a first comparison circuit that determines a normal end of the search operation when a match is found by comparing the data with the re-read data;
A second comparison circuit that compares the re-read data with the expected data when no error occurs in the re-read data and determines that the search operation has ended normally when a match is found. Disk processing unit.