JPH02179965A - Magnetic disk controller - Google Patents

Abstract

PURPOSE:To separately set an unreadable/unwritable sector, a read-only sector and a readable/writable sector by determining the possibility/impossibility of access to a data part by a comparing means. CONSTITUTION:A microprocessor circuit 30 outputs a seek instruction to an instructed cylinder, and when seeking operation is completed, the microprocessor circuit 30 reads data from the address of a main storage device 500, a SYNC byte and a CRC are added by a magnetic disk control circuit 20, and the data are written and formatted as an ID part to the magnetic disk device 200 with the data from the main storage part 500 as a FLAG byte, a sealing number, a track number and a sector number. In such a case, a value (a) is written when read/write is always permitted as the value of the FLAG byte, a value (b) is written when only read is permitted in a normal access level, and a value (c) is written when neither read nor write is permitted in the normal access level. Thus the sector which can be read only by a specific high-order device can be separately set.

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, a method for performing read and write operations or checking permission for write or read operations for a fixed sector type magnetic disk device having a sector TD for identifying each sector has been requested by a driver section of software. The first method is to check whether a read or write operation or a write or read operation is possible or not for a sector that has been written, using map information of the magnetic disk device expanded on the memory, or by setting a protect switch of the magnetic disk device.
A second method has been known in which the entire magnetic disk device is write-protected by turning it on.

Problems to be Solved by the Invention However, in the first method of the magnetic disk control device described above, when different software is used, the management method of the map information of the magnetic disk device is different, so that reading and writing to the requested sector is difficult. The disadvantage of the above-mentioned second method is that it is not possible to check whether the operation is possible or not.
If you set it to N, the entire magnetic disk drive will be write-protected.
There was a drawback that only the - section could not be write-protected.

The present invention was made in view of the conventional octopus described above,
SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a novel magnetic disk control device that makes it possible to eliminate the above-mentioned drawbacks inherent in the conventional technology.

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. successfully leads to the flag part within,
means for writing an access level for determining whether access to a writable data section is possible; means for determining the access level according to a command from a host device and storing the access level; and a read or write operation. At the same time, the flag part in the sector ID is read and the access level is compared with the contents of the means for storing the access level.
A sector for identifying each sector! When formatting a fixed sector type magnetic disk device with D, a write permission bit is written in the flag part of the sector ID to determine whether or not a write operation to the normally writable data area is possible. means for storing whether or not a write operation to the data portion of the same sector is possible when the write permission bit is reset by a command from a host device; Means for reading the flag part and comparing it with the contents stored by the above-mentioned storing means when the above-mentioned write permission bit was reset, and as a result of the comparison by the above-mentioned comparing means, data in the same sector that can be written normally is found. or a fixed-sector type magnetic disk device that has a sector ID for identifying each sector. A read command from the host device reads the data field when the target sector is detected by checking the ID field, and reads the above data. means for comparing the ID data of the higher-level device written by the means with the ID of the higher-level device that requested the read command, and if the result of the comparison by the comparison means matches, a data read operation is executed, and a mismatch is detected. In this case, the data reading operation is stopped.

EXAMPLE 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 first invention.

Referring to FIG. 1, the magnetic disk control device ID0 is
It is composed of a bus control circuit ID, a magnetic disk control circuit 20, a microprocessor circuit 30, a flag comparison circuit 50, and an access level storage circuit 60.

In addition, the magnetic disk controller z ioo controls the magnetic disk 2
00, and also connected to the central processing bag 2400 and the main storage device 500 via the bus 300.

The operation of the magnetic disk control device configured in this manner is as follows.

When a format command for the magnetic disk device 200 is input from the central processing unit 400 to the magnetic disk control device ID0 via the bus 300, the microprocessor circuit 30 centrally sends a format instruction to the magnetic disk device 200 via the magnetic disk control circuit 20. A seek command to the cylinder specified by the processing device 400 is output. When the seek operation is completed, the microprocessor circuit 30 reads the data from the address of the main storage device 500 instructed by the central processing unit 400, and the magnetic disk control circuit 20 reads the data from the second
The 5YNC bytes and CRC shown in the figure are added, and the data read from the main storage device 500 is written and formatted as a FLAG byte, cylinder number, track number, and sector number in the magnetic disk device t200 as an ID section. In this case, the FLAG written in the main storage device 500
As a byte value, set the value a to always allow reading and writing, value C to allow only reading at the normal access level, value C when neither reading nor writing is allowed at the normal access level. Here, the values of A, b, and c are set as c>b>a. Suppose that a write command is input from the central processing unit 400 to the magnetic disk control device ID0 via the bus 300 at access level a'' with the formatting operation for all cylinders completed in this way. outputs a seek command to the cylinder specified from the central processing bag W400 to the magnetic disk unit W, 200 via the magnetic disk control circuit 20, and sets a'' as the access level in the access level storage circuit 60. . When the seek operation is completed, the microprocessor circuit 30 starts a search operation for the magnetic disk control circuit 20 for data read from the magnetic disk device 200. When the 5YNC byte shown in FIG. 2 is detected by the magnetic disk control circuit 20, the magnetic disk control circuit 20 starts a FLAG byte detection operation. When the magnetic disk control circuit 20 detects the FLAG byte and outputs its value to the flag comparison circuit 50, the flag comparison circuit 50 compares the input FLAG byte data with the access level input from the access level storage circuit 60. Start the action. The results compared by the flag comparison circuit 50 are notified to the magnetic disk control circuit 20, and the magnetic disk control circuit 20 receives the results as “F”.
LAG byte"> access level a',
The sector is skipped and the search operation for the next sector is continued, and if “FLAG byte”≦access level “a”, the magnetic disk control circuit 20 uses the read data from the magnetic disk device 200 and the cylinder number. , track number, sector number, and CRC data checking. As a result, the microprocessor circuit 30 starts a write operation to the data portion if the target sector is the target sector and the CRC is 0; otherwise, the microprocessor circuit 30 skips that sector and starts writing to the next sector. Continue search operation.

FIG. 3 is a conceptual block diagram showing an embodiment of the second invention.

Referring to FIG. 3, the magnetic disk control device ID1 is composed of a bus control circuit ID, a magnetic disk control circuit 20, a microprocessor circuit 30, a flag comparison circuit 50, and a write level storage circuit 61.

Further, the magnetic disk control device ID1 controls the magnetic disk 20.
0, 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 in this manner is as follows.

When a format command for the magnetic disk device 200 is input from the central processing unit 400 to the magnetic disk control device ID1 via the bus 300, the microprocessor circuit 30 sends a format instruction to the magnetic disk device 200 via the magnetic disk control circuit 20. The processing device t 400 outputs a seek command to the designated cylinder. When the seek operation is completed, the microprocessor n30 reads the data from the address of the main storage device 500 instructed by the central processing unit 400, adds 5YNC bytes and CRC shown in FIG. 2 in the magnetic disk control circuit 20, and The data read from the main storage device 500 is FLAG byte,
The cylinder number, track number, and sector number are written and formatted as an ID part in the magnetic disk device 200. In this case, the F written in main memory l&500
When writing is always permitted as the value of the LAG byte, the value "1" is written, and when only reading is permitted at the normal access level, the value "0" is written.

When the formatting operation for all cylinders is completed in this way, the central processing unit 400 sends the bus 300
If a write command in a mode that does not permit write operations is input when the write permission bit in the flag has been reset for the magnetic disk control device ID1 via the Magnetic disk storage via! When the CPU 200 outputs a seek command to the cylinder specified by the central processing unit rf1400, the write level storage circuit 61 is set. When the seek operation is completed, the microprocessor circuit 30 starts a search operation for the magnetic disk control circuit 20 for data read from the magnetic disk device 200. When the 5YNC byte shown in FIG. 2 is detected by the magnetic disk control circuit 20, the magnetic disk control circuit 20
starts the FLAG byte detection operation. When the magnetic disk control circuit 20 detects the FLAG byte and outputs its value to the flag comparison circuit 50, the flag comparison circuit 50 compares the input FLAG byte data with the write level storage circuit 6.
The operation of comparing the input write permission bit with the input write permission bit starts from 1. The result of the comparison by the flag comparison circuit 50 is notified to the magnetic disk control circuit 20, and if the notified result indicates that writing is not permitted, the magnetic disk control circuit 20 skips reading that sector and performs the next operation. The search operation for the sector continues, and if writing is permitted, the magnetic disk control circuit 20 compares the read data from the magnetic disk device 200 with the cylinder number, track number, and sector number. and continues checking the CRC data. As a result, microprocessor circuit 3
0 is the target sector, and if the CRC is OK, a write operation to the data portion is started; otherwise, the sector is skipped and the search operation for the next sector is continued.

FIG. 4 is a conceptual block diagram showing an embodiment of the third invention.

In FIG. 4, the magnetic disk control device ff ID2 is composed of a bus control circuit ID, a magnetic disk control circuit 20, a microprocessor 30, a channel ID comparison circuit 51, and a channel ID storage circuit 62. Further, the magnetic disk control device fiID2 is connected to the magnetic disk 200 and connected to the central processing unit 400 via the bus 300.
and main memory]! 500 is connected.

The operation of the magnetic disk control device configured in this manner is as follows.

Assuming that a write command is input from the central processing unit ff 400 to the magnetic disk control unit 2ID0 via the bus 300, the microprocessor circuit 30 sends the central processing unit to the magnetic disk unit 200 via the magnetic disk control circuit 20. 400 outputs a seek command to the designated cylinder. When the seek operation is completed, the microprocessor circuit 30 starts a search operation for the magnetic disk control circuit 20 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 20 as shown in FIG. The ID code of the central processing unit 400 that outputs the write command is output, and then the data to be written on the medium is output from the main storage device 500 via the bus 300 and the bus control circuit ID. 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, if a read command is input from the central processing unit 400 to the magnetic disk controller ID2 via the bus 300, the microprocessor circuit 30 inputs the channel ID
The channel ID of the central processing unit 400 is stored in the storage circuit 62, and a seek command to the cylinder designated by the central processing unit 400 is output to the magnetic disk device 200 via the magnetic disk control circuit 20. When the seek operation is completed, the microprocessor circuit 30 starts a search operation for the magnetic disk control circuit 20 to search the magnetic disk device 200 for a target sector.

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 20 to perform a 5YNC byte search operation. When the search operation for 5YNC bytes is completed and the channel ID is read from the medium and output from the magnetic disk control circuit 20, the microprocessor circuit 30
starts an operation in which the channel ID comparison circuit 51 compares the channel ID output from the channel ID storage circuit 62 and the channel ID output from the magnetic disk control circuit 20. As a result of the comparison, if they match, the microprocessor circuit 30 reads out the data written after the channel ID as read data, and reads out the data written after the channel ID, the bus control circuit ID, the bus 300, and the main memory! Transfer data to E500.

If the comparison results in a mismatch, the microprocessor circuit 30 notifies the central processing unit 400 that there is a mismatch and ends the operation.

As described in detail of the invention, by employing the magnetic disk control device according to the first invention, if the access level of each sector in the magnetic disk device is determined in advance by formatting, the above-mentioned Depending on the access level of the command from the device, it is possible to individually set sectors that are not readable and writable, sectors that are only readable, and sectors that are readable and writable.

By adopting the magnetic disk control device according to the second aspect of the present invention, if the setting or resetting of the write permission bit of the flag of each sector in the magnetic disk device is determined in advance by formatting, the above device can With this command, read-only sectors and read/writable sectors can be individually set.

Furthermore, by employing the magnetic disk control device according to the third invention, it becomes possible to individually set sectors that can be read only by a specific host device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the first invention;
Figure 2 is a diagram showing an example of the sector ID format,
FIG. 3 is a block diagram showing an embodiment of the second invention;
FIG. 4 is a block diagram showing an embodiment of the third invention;
FIG. 5 is a diagram showing an example of the format of the data section. ID...Bus control circuit, 2o...Magnetic disk control circuit, 30...Microprocessor circuit, 5o...
Flag comparison circuit, 51...Channel ID comparison circuit, 6
o...Access level storage circuit, 61...Write level storage circuit, 62...Channel ID storage circuit, ID0
．． ID1. ID2...Magnetic disk control device, 200
...Magnetic disk device, 300...Bus, 400...
...Central processing unit, 500...Main storage device Patent applicant NEC Corporation Representative Yutabe Kumagai Figure 1

Claims (3)

[Claims] (1) For a fixed sector type magnetic disk device that has a sector ID for identifying each sector, when formatting, the flag part in the sector ID can be read and written normally, and the data part can be accessed. means for writing an access level to determine whether or not to be permitted; means for determining the access level based on a command from a host device and storing the access level; and reading a flag portion in the sector ID during a read or write operation. means for comparing the flag part with the contents of the means for storing the access level; and as a result of the comparison by the comparison means, it is possible to access the data part in the same sector that can be read and written normally;
1. A magnetic disk control device comprising means for determining whether or not the disk is prohibited. (2) For a fixed sector type magnetic disk device that has a sector ID to identify each sector, it is possible or impossible to write to the data section that can be normally written to the flag part in the sector ID during formatting. means for writing a write permission bit to determine the write permission bit, and storing whether a write operation to the data portion of the same sector is possible or not when the write permission bit is reset by a command from the host device. means for reading the flag part in the sector ID during a write operation and comparing it with the content stored by the storing means when the write permission bit was reset; 1. A magnetic disk control device comprising means for determining whether or not a write operation to a normally writable data portion of the magnetic disk is permitted or prohibited. (3) Means for writing data after writing the ID data of the host device to the beginning of the data section in response to a write command from the host device in a fixed sector type magnetic disk device having a sector ID for identifying each sector. Then, when the target sector is detected by checking the ID field due to a read command from the host device, the data field is read and the ID data of the host device written by the above means and the ID of the host device that requested the read command are read. A magnetic disk control device comprising: means for comparing; and means for executing a data read operation if the results of the comparison by the comparison means match, and stopping the data read operation if they do not match.