JPH036614A - Magnetic disk controller - Google Patents

Abstract

PURPOSE:To prevent the transformation of data by reading the data when the coincidence is obtained between the physical device number of a magnetic disk device which is written by a data writing means with the physical device number of the magnetic disk device which is pointed by a reading instruction issued from a host device. CONSTITUTION:A microprocessor circuit 30 compares the physical device number received from a physical device number storage circuit 60 with the physical device number received from a magnetic disk control circuit 20 via a physical device number comparator 50. When the coincidence is obtained between both device numbers, the data written after the physical device numbers are read out as the read data and sent to a bus control circuit 10, a bus 300, and a main storage 500. Thus it is possible to prevent such a case where a host device reads data out of an undesired magnetic disk device 200, i.e., the transformation of data.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic disk control device used in an information processing device.

2. Description of the Related Art Conventionally, as a method for checking read operations on a fixed sector type magnetic disk device that has a sector ID for identifying each sector, the device number of the magnetic disk device instructed by the host device is used to check the read operation of the magnetic disk device. A method is known in which a selection operation is performed and this is checked by receiving and receiving a signal indicating that the selection has been made from the magnetic disk device.

Problems to be Solved by the Invention However, in the above-mentioned magnetic disk control device system, a signal indicating that a magnetic disk device with a device number other than the device number of the magnetic disk device instructed by the host device is selected due to a failure. There is a drawback that when a magnetic disk device is selected and data is read from a device other than the desired magnetic disk device, data may be garbled.

The present invention has been made in view of the above-mentioned conventional situation,
SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a novel magnetic disk control device that eliminates the above-mentioned drawbacks inherent in the conventional technology and makes it possible to prevent the so-called data corruption.

Means for Solving the Problems In order to achieve the above object, a magnetic disk control device according to the present invention provides a fixed sector type magnetic disk device having a sector ID for identifying each sector. A means for writing data after writing the physical device number of the magnetic disk device to the beginning of the data section by a write command, and a means for writing data after a write command writes the physical device number of the magnetic disk device to the beginning of the data section, and a means for writing the data section when the target sector is detected by checking the ID section by a read command from the host device. Read A means for comparing the physical device number of the magnetic disk drive written by the data writing means with the physical device number of the magnetic disk drive instructed by the read command from the host device, and the result of the comparison by the comparison means. If they match, the data is read out, and if they do not match, the data reading operation is stopped.

Embodiment Next, a preferred embodiment of the present invention will be specifically explained with reference to the drawings.

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

In FIG. 1, a magnetic disk control device 1 according to the present invention
100 is composed of a bus control circuit lO1 magnetic disk control circuit 20, a microprocessor circuit 30, a physical device number comparison circuit 50, and a physical device number storage circuit 60.

Further, the magnetic disk control device 100 includes a magnetic disk 2
00, and is also connected to a central processing unit 400 and a main storage device 500 via a bus 300.

The operation of the magnetic disk control device configured as described above is as follows. Assuming that a write command is input from the central processing unit 400 to the magnetic disk control device 100 via the bus 300, the microprocessor #I30 inputs the write command to the magnetic disk device 20 via the magnetic disk control circuit 20.
0, outputs a seek command to the cylinder specified by the central processing unit 400.

When the seek operation is completed, the microprocessor circuit 30
starts a search operation for the magnetic disk control circuit 2o to search for a target sector from the magnetic disk device 200.

When the notification that the search operation is completed is input from the magnetic disk control circuit 20, the microprocessor circuit 30 first outputs 5YNC bytes to the magnetic disk control circuit 2o as shown in FIG. The physical device number of the magnetic disk device 200 specified by the write command is output, and the data to be written on the medium is then written to the main storage device j5.
00, the signal is output via the bus 3oo and the bus control circuit 10. When all the data of one sector is written, the magnetic disk control circuit 20 writes the FCC data and ends the write operation.

Next, when a read command is input from the central processing unit 400 to the magnetic disk control device 100 via the bus 300, the microprocessor circuit 3o instructs the physical device number storage circuit 60 to identify the physical device designated by the read command. It memorizes the number and outputs a seek command to the cylinder instructed by the central processing unit 400 to the magnetic disk device 200 via the magnetic disk control circuit 20. When the seek operation is completed, the microprocessor circuit 30 instructs the magnetic disk control circuit 20 in the magnetic disk drive 200.
The search operation for searching for the target sector is started from there.

When a notification that the search operation is completed is input from the magnetic disk control circuit 20, the microprocessor 30 instructs the magnetic disk control circuit 2o to perform a 5YNC byte search operation. When the search operation for 5YNC bytes is completed and the physical device number is read from the medium and output from the magnetic disk control circuit 20, the microprocessor circuit 3o stores the physical device number output from the physical device number storage circuit 60, and The operation of comparing the physical device numbers output from the magnetic disk control circuit 20 by the physical device number comparison circuit 5o is started. The microprocessor circuit 30 reads out the data written after the physical device number as read data if they match as a result of the comparison by the physical device number comparison circuit 50, and reads out the data written after the physical device number as read data, and reads the data written after the physical device number as read data, Transfer data to 500. In addition, if there is a discrepancy as a result of the comparison,
The microprocessor circuit 30 notifies the central processing unit 400 of the mismatch, and ends the operation without starting the read operation.

As described in detail, by employing the magnetic disk control device according to the present invention, it is possible to prevent a host device from reading data from an unintended magnetic disk device, that is, to prevent data corruption. Become.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG.
The figure shows an example of the format 1-format of the data section. DESCRIPTION OF SYMBOLS 10... Bus control circuit, 20... Magnetic disk control circuit, 30... Microprocessor circuit, 50...
Physical device number comparison circuit, 60... Physical device number storage circuit, 100... Magnetic disk control unit, 200
...Magnetic disk device, 300...Bus, 400...
・Central processing unit, 500 ・Main memory

Claims (1)

[Claims] means for writing data after writing a physical device number of a magnetic disk device to the beginning of a data section in accordance with a write command from a host device to a fixed sector type magnetic disk device having a sector ID for identifying each sector; When the target sector is detected by checking the ID section according to a read command from the host device, the data section is read out, and according to the physical device number of the magnetic disk device written by the data writing means and the read command from the host device. It has means for comparing the physical device number of the designated magnetic disk device, and means for executing the data read operation if the result of the comparison by the comparison means is a match, and if it is a mismatch, stopping the data read operation. A magnetic disk control device characterized by: