JPH04273318A - Data updating system for magnetic disk controller - Google Patents

Abstract

PURPOSE:To improve the reliability of data without causing any unrecoverable error. CONSTITUTION:A reading means 7 reads the updating object data out of a magnetic disk device 3 and sends them to a buffer memory 4, and a comparison means A5 compares the read updating object data with the original updating object data. Then a reception means 8 receives the updating data from a host processor 1 and sends them to the memory 4 to update the data. A comparison means B6 compares the updated data with the original updating data. A writing means 9 writes updated data stored in the memory 4 into the device 3, and the means A5 compares the written updated data with the original updated data.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data update method for a magnetic disk control device that writes updated data to a magnetic disk device in response to a data update request, and more particularly to a data update method that improves the reliability of updated data.

0002

2. Description of the Related Art Conventionally, when updating data, magnetic disk devices can only read and write data in units of physical sectors. Therefore, when updating data in units of logical sectors within physical sectors, 5, first, the data in physical sector units on the buffer memory of the magnetic disk controller is read from the magnetic disk device (see arrow 41, step 51), and then data is read out from the host processor (in logical sector units). Update the data on the buffer memory (see arrow 42, step 52),
Data in units of physical sectors including updated logical sectors was written to the magnetic disk device (see arrow 43, step 53).

0003

[Problems to be Solved by the Invention] In the above-described conventional data update in a magnetic disk device in units of logical sectors, if the data before writing is incorrect in each step shown in FIG. The disadvantage is that it becomes impossible to recover the data and the reliability of the data decreases.

0004

[Means for Solving the Problems] The present invention provides a data update method for a magnetic disk control device having a buffer memory, which comprises: a reading means for reading data to be updated from the magnetic disk device into the buffer memory; a first comparing means for comparing and comparing the update target data read out with the original update target data; a receiving means for receiving update data from a host device and updating the update target data on the buffer memory; , comprising a second comparison means for comparing and collating the updated data on the buffer memory with the original update data, and a writing means for writing the updated data on the buffer memory into the magnetic disk device, The first comparing means compares and checks the updated data written in the magnetic disk device with the original updated data.

[0005]

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

FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, the magnetic disk control device 2 of this embodiment includes a buffer memory 4, a receiving means 8 for receiving data onto the buffer memory 4 from a host processor 1 which is a host device, and a comparing means B6 for comparing and collating the received data. , an address means 10 for instructing the address of data to be written in the buffer memory 4, a reading means 7 for reading data from the magnetic disk device 3 onto the buffer memory 4, and a writing device for writing data on the buffer memory 4 into the magnetic disk device. 9, comparison means A5 for comparing and collating data read and written to the magnetic disk device, and a microprocessor 11 for controlling each of these means.

Next, the operation of this embodiment will be explained.

FIG. 2 is a diagram illustrating the update procedure according to this embodiment.

FIG. 3 is a flowchart showing the processing according to this embodiment. In FIGS. 2 and 3, when the host processor 1 receives a data update command for the magnetic disk device, for example, a request to update data in the logical sector 27, the magnetic disk control device 2 first sends the data to the magnetic disk device via the reading means 7. 3, data in units of physical sectors including the logical sector to be updated is read onto the buffer memory 4 (see arrow 21 and step 31). Next, the data on the buffer memory 4 and the data on the original magnetic disk device 3 are compared and checked by the comparison means A5 (check by exclusive OR circuit), and it is determined whether they are the same (arrow 22,
(See step 32). If they are the same, proceed to the next process; if they are different, the processes of steps 31 and 32 are repeated again.

Subsequently, the address means 10 specifies the address of the buffer memory 4, and the update data is sent from the host processor 1 to the buffer memory 4 via the receiving means 8.
Move up and update the data (see arrow 23, step 33). The updated data and the original data of the host processor 1 are compared and checked by the comparing means B6 (check by exclusive OR circuit) to determine whether they are the same (see arrow 24, step 34). If they are the same, proceed to the next process; if they are different, repeat steps 33 to 3.
Repeat step 4.

Furthermore, the updated data on the buffer memory 4 is written to the magnetic disk device 3 via the writing means 9 (see arrow 25, step 35). The written data and the data on the original buffer memory 4 are compared and checked by the comparison means A5 (checked by an exclusive OR circuit), and it is determined whether they are the same (
(see arrow 26, step 36). If they are the same, proceed to the next process; if they are different, repeat steps 35 to 36.
Repeat the process.

[0012] As a result, error-free data updating is performed on the magnetic disk device.

[0013]

[Effects of the Invention] As explained above, the magnetic disk control device of the present invention always compares and verifies data with the original data each time data is moved, so that it is possible to avoid the occurrence of irrecoverable errors. This has the effect of improving data reliability.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram illustrating an update procedure according to this embodiment.

FIG. 3 is a flowchart showing processing according to this embodiment.

FIG. 4 is a diagram illustrating a conventional update procedure.

FIG. 5 is a flowchart showing conventional processing.

[Explanation of symbols]

1 Host processor 2 Magnetic disk control device 3 Magnetic disk device 4 Buffer memory 5 Comparing means A 6 Comparing means B 7 Reading means 8 Receiving means 9 Writing means 10 Addressing means 11 Microprocessors 21 to 26 Arrows (data flow) 27
logical sector

Claims (1)

[Claims] 1. A data update method for a magnetic disk control device having a buffer memory, comprising: reading means for reading update target data from a magnetic disk device into the buffer memory; and the update target data read onto the buffer memory. a first comparison means for comparing and collating data with the original data to be updated; a receiving means for receiving update data from a host device and updating the data to be updated on the buffer memory; and a first comparison means for comparing data with the original data to be updated; a second comparing means for comparing data with the original updated data; and a writing means for writing the updated data on the buffer memory into the magnetic disk device; A data update method for a magnetic disk control device, characterized in that the updated data written in the magnetic disk device is compared and verified with the original updated data.