JPH01163822A - Magnetic disk control device - Google Patents

Abstract

PURPOSE:To prevent an occupied state from being forcibly transferred to a self-system and the occupied state of other system from being canceled with any conditions by once stopping the output of a unit selecting signal, then setting a priority selecting signal, and outputting the unit selecting signal again when the occupation of a magnetic disk device is confirmed. CONSTITUTION:When a microprocessor circuit 20 recognizes that a magnetic disk device 200 has been occupied, it once resets a unit selector circuit 51, resets the unit selecting signal, then sets a priority selector circuit 52, outputs the priority selecting signal, sets the unit selector circuit 51 again, and outputs the unit selecting signal. Thus, the other magnetic disk device connected by the cables arranged in the same 'one after another' system as the magnetic disk device in the occupied condition in the self-system can be simultaneously occupied to the self-system, and when the device is occupied by the self system, the occupied state of the other system can be prevented from being canceled without any conditions.

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.

Conventional technology Conventionally, in a magnetic disk control device that controls an SMD interface magnetic disk device having a dual port mechanism, as a method for making the own system occupy the magnetic disk device, there is a method of using only a unit select signal without using a priority select signal. How to select and occupy a magnetic disk device.

There is a method of forcing the own system to occupy the unit by outputting a priority select signal when the unit select signal is output.

Problems to be Solved by the Invention However, in the first method of the conventional magnetic disk control device described above, it is effective only when the unit select signal is output and when other systems are not using the priority select signal. In addition, when connecting cables using the imozuru method, there is a drawback that magnetic disk drives other than the currently occupied magnetic disk drive cannot be occupied at the same time, or other systems set the priority select signal during operation, causing the unit select signal to be set. If this is output, there is a drawback that the exclusive state of the own system is forcibly released.

In addition, in the second method above, if the other system occupies the magnetic disk device only by the unit select signal, setting the priority select signal and outputting the unit select signal will force the own system to occupy the magnetic disk device. There was a drawback that the state would change and the occupied state of the other system would be released unconditionally.

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 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 objects, a magnetic disk control device according to the present invention includes means for outputting a unit select signal to an SMD interface magnetic disk device having a dual port mechanism; means for detecting that a unit selected signal indicating that the magnetic disk device has been selected is returned after a certain period of time after outputting the select signal and that the magnetic disk device is not in a busy state; When it is confirmed that the disk device is occupied, the device stops outputting the unit select signal, sets the priority select signal, and outputs the unit select signal again.

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, 1 a magnetic disk control device 1 according to the present invention;
00 is the bus control circuit 10. Microprocessor circuit 2
0. Magnetic disk control circuit 30. It is composed of a unit select circuit 51, a priority select circuit 52, and a selection circuit 53.

Further, the magnetic disk control unit 100 controls a magnetic disk device (
A) 200 and magnetic disk device t(B) 201, and is connected to the central processing unit 40 via a path 300.
0 and main memory! 500 is connected.

The operation of the magnetic disk control unit 100 configured in this manner is as follows.

Magnetic disk device (A) 20 from the central processing unit 400
Read command for 0 and magnetic disk device (B) 201
If a write command to the magnetic disk device (A) 200 is input to the magnetic disk controller 100 via the bus 300, the microprocessor circuit 20 starts a seek operation for the magnetic disk device (A) 200.
) 200, sets the unit select circuit 51, and outputs a unit select signal to the magnetic disk device (A) 200. After a certain period of time has elapsed, the microprocessor circuit 20 inputs the status of the magnetic disk device (^) 200 through the selection circuit 53. As a result of analyzing the input status, if it is not in a busy state and the unit select signal is set, the microprocessor circuit 20 recognizes that the magnetic disk device (A) 200 is occupied, and - After resetting the unit select circuit 51 and resetting the unit select signal, the priority select circuit 52 is set to output the priority select signal, and the unit select circuit 51 is set again to output the unit select signal.

When the microprocessor circuit 20 recognizes that the magnetic disk device (^) 200 is in the forced occupancy state, it outputs a seek command to the magnetic disk device ft(A) 200. The seek operation starts when the magnetic disk device @ (A
) 200, the microprocessor circuit 20 resets the unit select circuit 51, resets the unit select signal, and disconnects the magnetic disk device (A) 200. Here, the magnetic disk device (A) zoo is in a state separated from the magnetic disk control unit 100, but the magnetic disk control unit 100
The state of occupancy will continue.

Similarly, the microprocessor circuit 20 activates the seek operation of the magnetic disk device (B) 201 and places it in the disconnected state while remaining in the occupied state.

Next, the microprocessor circuit 20 checks the status of the magnetic disk device (A) 200 and the magnetic disk device (B) 201 to determine whether the seek state has ended.

Assuming that the magnetic disk device (A) 200 finishes the seek operation first, the microprocessor circuit 20
After setting the unit select circuit 51 and outputting a unit select signal to bring it into a connected state.

Start read operation. The read data is sent to the magnetic disk control circuit 30. The data is written to the main memory device 500 via the bus control circuit IO and the bus 300. When the read operation is completed, the microprocessor circuit 20 outputs a release command to the magnetic disk device (A) 200, resets the unit select circuit 51, and resets the unit select signal to release the magnetic disk device (A).
) 200 is released from the occupied state and placed in a disconnected state.

As described in detail, by employing the magnetic disk control unit of the present invention, it is possible to simultaneously control a magnetic disk device that is occupied in the own system and another magnetic disk device that is connected to the same Imozuru type cable. It becomes possible to occupy the system, and the disadvantage that the occupied state of other systems is unconditionally canceled when the own system occupies the system can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. 10. , bus control circuit, 20. , ,Microprocessor circuit, 30. , , magnetic disk control circuit, 51°0. Unit selection circuit, 52. , ,
Priority select circuit, 53. , ,Selection circuit, 100. , . magnetic disk control unit, 200. , , magnetic disk device (A), 201. , ,Magnetic disk device (B)
, 300. , . Bus, 400. , , central processing unit, 500. ,
, main memory

Claims (1)

[Claims] Means for outputting a unit select signal to a magnetic disk device with an SMD interface having a dual port mechanism, and a unit selected signal indicating that the unit has been selected from the magnetic disk device after a certain period of time after outputting the unit select signal. means for detecting that the magnetic disk drive has been returned and that the magnetic disk drive is not in a busy state; and a unit select signal is set once the output of the unit select signal is stopped when the detection means confirms that the magnetic disk drive is occupied, and then a priority select signal is set. 1. A magnetic disk control device, comprising means for outputting a unit select signal again.