JPH05173718A - Magnetic disk subsystem - Google Patents

Abstract

PURPOSE:To considerably shorten the occupancy time of a magnetic disk controller (DKC) in processing per device by enabling multiple control from the DKC to another magnetic disk unit (DKU), as well during input/output time from write in a cache to write in a disk drive while waiting for an end report due to write in a magnetic disk. CONSTITUTION:A data write instruction from a host device 0 is transmitted through a first interface 5 to a DKC 1, a DKC control part 15 issues the data write instruction through a second interface 6 to a DKU 2, data are written in a temporary storage part 23, a control part 22 executes the first end report to the DKC, the second interface is released for holding the processing with the DKC, the data are written from the temporary storage part to a magnetic disk 21 and corresponding to processing restarting access from the DKC, the second end report is transmitted. During the period of the first and second end reports, the DKC executes the multiple control to the other DKU.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control of a magnetic disk device using a high speed temporary storage device by a magnetic disk control device, and more particularly to a control system at the time of writing.

[0002]

2. Description of the Related Art There are roughly two types of control methods for writing data in a magnetic disk drive using a conventional high-speed temporary storage device such as a cache.

The processing ends when the data is transferred to the cache. In other words, when the writing to the cache is completed, a report is sent to the higher-level device and the processing is terminated. When the data transfer to the cache is terminated, the processing is terminated, so that extremely high-speed data transfer is possible. However, when writing the data written in the cache to the magnetic disk drive, if any failure occurs, the completion report is sent to the upper-level device, so that the control for reprocessing becomes very complicated.

Alternatively, it is a method in which the processing is not completed until the data is written in the magnetic disk drive. In other words, the processing is not completed until the data written in the cache is written to the magnetic disk, or a method is used to write directly to the magnetic disk by providing a path that does not use the cache. There is no complicated control.

[0005]

In the magnetic disk subsystem composed of the above-described conventional magnetic disk control device and cached magnetic disk device,
As described above, the magnetic disk control device completes the processing when it receives the data write completion report in the cache, and therefore the transfer speed becomes very fast. However, for example, if a failure such as a power failure occurs while writing data from the cache to the disk, even if the data could not be written normally, the normal completion report has already been sent to the host device. Therefore, this recovery process requires the addition of a large amount of processing functions on the host device side.

Further, as described above, since the magnetic disk control device waits for the end report by writing to the magnetic disk even after writing to the cache, the processing time becomes longer than the cacheless magnetic disk by the input / output time of the cache. And the time from writing to the cache to writing to the magnetic disk, DKC
Has a problem that it cannot process with other DKU.

The present invention has been made in view of the above problems, and enables multiple control of the magnetic disk device DKU by the magnetic disk control device DKC without burdening the host device with the recovery processing. An object is to provide a magnetic disk subsystem that reduces the occupancy time of DKC in processing.

[0008]

In the magnetic disk subsystem of the present invention, a magnetic disk control device DKC and a DKC second interface are separately connected to a plurality of host devices by a first interface. Thus, in a magnetic disk subsystem for inputting / outputting data, which is connected to a plurality of magnetic disk devices DKU and is composed of at least one DKC and a DKU group,
The DKU has a high-speed storage means for temporarily storing the read data and the written data, and a data write command from the DKU to the DKC when the writing of the data to the high-speed storage means of the DKU is completed. A means for making a first end report; and, when the first end report is sent out, a process with the DKC is temporarily suspended by an instruction of the DKC.
Means for releasing the interface, a means for waiting for an access from the DKC to prepare for the second end report when the data in the high-speed storage means is written on the magnetic disk, and the second end report. Has a means for not accepting access requests from other DKCs.

Further, when the DKC finishes writing to the high-speed storage means of the DKU by a data write command from a host device using the first interface, DK
A means for receiving a first end report from U and reporting the error to the host device if there is an error, and a command for temporarily suspending processing with DKU if there is no error at the time of the first end report.
Means for issuing to KU and releasing the second interface;
It has means for issuing an instruction to restart the processing with the DKU that has suspended the processing, and means for issuing a completion report to the host device by receiving the second completion report from the DKU when the processing is restarted.

Further, the DKC has means for calculating the time for estimating that the second end report is prepared from the first end report, and a maximum number of timers equivalent to the number of DKUs connected under the means. A means for setting the calculated time in a timer, a means for controlling a host device other than the currently held upper device and the held DKU until the timer is turned on, and accessing the held DKU when the timer is turned on It has a means for receiving the second completion report.

[0011]

According to the above-mentioned structure, the DKU makes the first write to the DKC when the data write to the high-speed storage means of the DKU is completed in accordance with the data write command from the DKC.
The end report of DKC based on the first end report
2nd to suspend processing with DKC by the command from
The interface is released, the data in the high-speed storage means is written to the magnetic disk and the second completion report is prepared to wait for the access from the DKC, and the access request from the other DKC is not accepted during this period.

On the other hand, the DKC receives the first end report from the DKU, reports any error to the host device, and if there is no error, issues a command to suspend processing with the DKU and release the second interface. After that, an instruction for restarting the processing is issued to the DKU, the second end report is received, and the end report is sent to the host device.

Alternatively, the DKC calculates the estimated time for preparing the second completion report from the first completion report of the DKU, and calculates the estimated time calculated by the timers installed in the same number corresponding to each of the subordinate DKUs. When the timer is set, control is performed for the host device and the DKU other than the currently-held higher-order device, and when the timer expires, the pending DKU is accessed to receive the second end report. The time from the reception of the end report to the reception of the second end report can be used for the processing of other DKUs to enable multiple control of the DKU and reduce the occupied time of the DKC.

[0014]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of a magnetic disk subsystem according to an embodiment of the present invention.

In the figure, reference numeral 1 is a magnetic disk controller (DKC). 2, 3 and 4 are magnetic disk units (DKU) including a temporary storage function. Reference numerals 11, 12, 13, and 14 in the magnetic disk control device are host device interface control units that control the first interface with the host device.
Device interface control units 16 and 17 control the second interface with the DKUs 2, 3 and 4. Also,
Reference numeral 15 is a control unit having a function of decoding an instruction from the host, issuing an instruction to the DKUs 2, 3 and 4, writing the data sent from the host to the DKU and sending the data from the DKU to the host device. 21, 31 in the magnetic disk device 2, 3
Is a magnetic disk drive. Reference numerals 22, 32, and 42 are control units that control the magnetic disk drives 21 and 31, the temporary storage function, and the end report. Further, reference numerals 23, 33, and 43 are temporary storage units for temporarily storing input / output data of the drive.

The DKU1 is individually connected to the host device by means of the first interface 5. In addition, DKC1 and the DKU group 2, 3, by the second interface 6
4 is connected.

FIG. 2 is a block diagram of the magnetic disk device of the present invention.

The DKU shown in the figure will be described by taking the DKU2 as an example. The device interface port unit 51 constituting the control unit 22 of the DKU2 has a function of controlling the interface with the DKC1 and transmitting the end information. 52 is connected to the device interface port unit 51, and after issuing the first completion report, sends DK until the second completion report is transmitted.
This is a device-occupying circuit having a function of making U2 inaccessible to other DKCs. Reference numeral 53 denotes a temporary storage unit 23 for input / output data and a device interface port unit 5.
1 and a plurality of DKCs connected to the magnetic disk controller
Is a temporary storage control unit for controlling the temporary storage unit such as analyzing the command from the DKC and writing the data from the DKC to the temporary storage unit 23. Similarly to 53, the magnetic disk drive 57 is connected to the magnetic disk drive 21 and the device interface port unit 51, analyzes the command from the DKC 1, and writes the data from the temporary storage unit 23 to the magnetic disk drive 21. It is a magnetic disk control unit that performs control regarding. Reference numeral 55 denotes a first end report transmission unit, which causes the temporary storage control device 53 to transfer data from the DKC 1 to the temporary storage unit 2.
When the writing is completed in 3, the device interface port unit 51 is instructed to send the first end report.
Further, reference numeral 56 denotes a second end report sending unit, which writes the data in the temporary storage unit 23 to the magnetic disk drive 21 to send a second end report to the device interface port unit 51.
Instruct to send a completion report.

FIG. 3 is a block diagram of the magnetic disk controller of the present invention.

In the figure, reference numerals 11, 12, 13, 14 constitute a host device interface control unit DKC control unit 15. Reference numeral 65 denotes a data processing unit that edits data from the host device or device into a required form and transfers the data to the host device or device. Reference numeral 66 denotes a host device interface control unit 11, 12, 13, 14, a data processing unit 65, and a device interface control unit 16, 1.
7 is a control unit that is connected to the control unit 7 and has a function of defining the operation of the DKC 1. 18 is a programmable timer controlled by the controller 66. 16 and 17 are lower devices,
Here, the device interface control unit controls the interface with the DKU.

Next, the operation will be described.

The magnetic disk controller DKC1 shown in FIG.
A command to write data from the host device 0 to a subordinate magnetic disk device (denoted as DKU2) is issued by the host interface 11
If the control unit 66 accepts via the
6 through the device interface control unit 16,
The procedure of data transfer with the DKU2 is performed, and the transfer is started. The transfer at this time is performed by transferring the data sent from the higher-level device 0 between the temporary storage units 23 of the DKU2 via the DKC1, and when the transfer ends, the first end report sending unit 55 sends a first end report, The data is transferred to the DKC1 via the device interface port unit 51.

When the control unit 66 of the DKC 1 receives this first end report via the device interface control unit 16, if there is an error in that information, it is sent to the higher level device 0 via the higher level device interface control unit 11. If there is no report, if there is no report to the higher-level device, a command for temporarily suspending the process with the DKU2 is sent to the DKU2 via the device interface control unit 16, and the second interface is released. .. Further, at this time, the data control unit 66 sets in the timer 18 the estimated time for the data written in the temporary storage unit 23 of the DKU 2 to be written in the magnetic disk drive 21. Until this timer runs out, DKC1 accepts commands other than host device 0
Control other than KU2 can be performed, and waste of processing time due to physical operation can be effectively used. After that, when the control unit 66 of the DKC confirms that the timer 18 has run out, the DKU 2 is accessed and the second end report is received via the device interface port unit 51. At this point, the host device 0 is notified of the end, and the series of processes ends.

On the DKU2 side, the temporary storage control unit 53 and the magnetic disk control unit 57 are connected to the magnetic disk drive 2
The data written in the temporary storage unit 23 is written to the magnetic disk drive 21 while performing processing such as waiting for rotation of 1. When the data written in the temporary storage unit 23 has been written to the magnetic disk drive 21, the second end report sending unit 56 prepares a second end report, and
Wait for KC1 access.

After issuing the first completion report, the DKU2 terminates the dialogue with the DKC1 once by the instruction of the DKC1 which issued the first completion report, and receives the connection request from the DKC1 again. The second interface 6 is released. At this time, the device occupancy circuit 52 does not accept an access from another DKC and sets it in the occupied state. After that, when the connection request is received from the DKC 1 that has received the report of the first end report, this is accepted and the second end report is transmitted.

[0027]

As described above, in the magnetic disk subsystem of the present invention, when data is written in the high speed magnetic disk device with the temporary storage mechanism, the first end is caused by the fact that the data is written in the temporary storage. A function to perform two end reports, that is, a report and a second end report due to the data in the temporary storage being written in the magnetic disk drive, and the magnetic disk controller DKC receives the first end report. The function of using the time from the reception of the second end report to the processing of other DKUs makes it possible to perform multiplex control of the device and significantly reduce the occupying time of the DKC in the processing per device. ..

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a magnetic disk subsystem according to an embodiment of the present invention.

FIG. 2 is a block diagram of a magnetic disk device of the present invention.

FIG. 3 is a block diagram of a magnetic disk control device of the present invention.

[Explanation of symbols]

 1 Magnetic Disk Controller 2, 3, 4 Magnetic Disk Device 5 First Interface 6 Second Interface 11, 12, 13, 14 Upper Interface Controller 15 DKC Controller 16, 17 Device Interface Controller 18 Timer 21, 31 Magnetic disk drive 23, 33, 43 Temporary storage unit 22, 32, 42 DKC control unit 51 Device interface port unit 52 Device I occupation circuit 53 Temporary storage control unit 55 First end report sending unit 56 Second end report sending unit 57 Magnetic Disk control unit 65 Data processing unit 66 Control unit

Claims (3)

[Claims] 1. A magnetic disk control device D which is individually connected to a plurality of host devices by a first interface.
In a magnetic disk subsystem for inputting and outputting data including a KC, the DKC being connected to a plurality of magnetic disk devices DKU by a second interface, and the data being composed of at least one of the DKC and the DKU group, The DKU stores in the DKC a high-speed storage means for temporarily storing the read data and the write data, and when the data writing to the high-speed storage means of the DKU is completed by a data write command from the DKC. On the other hand, means for making a first end report, means for temporarily suspending processing with the DKC and releasing the second interface by the instruction of the DKC when the first end report is sent out, When data is written to the magnetic disk, a means for preparing for the second completion report and waiting for access from the DKC, A magnetic disk subsystem characterized in that it has means for not accepting an access request from another DKC until the second completion report is sent to the DKC. 2. The DKC uses the first interface to write the DK in response to a data write command from a host device.
When the writing to the high-speed storage means of U is completed, the DKU
Means for receiving an error from the first end report and reporting the error to the host device; and if there is no error at the time of the first end report, once the DK
Means for issuing a command for suspending processing with U to the DKU to release the second interface; means for issuing instruction for restarting processing with the DKU for which processing has been suspended; 2. The magnetic disk subsystem according to claim 1, further comprising means for sending an end report to the host device by receiving the second end report from the DKU at times. 3. The DKC has means for calculating a time for estimating that a second completion report is prepared from the first completion report, and a maximum number of timers equal to the number of DKUs connected under the maximum completion report. A means for holding the calculated time in the timer, a means for controlling a host device other than the currently held upper device and the held DKU until the timer is turned on, and a means for controlling the held DKU when the timer is turned on. 3. The magnetic disk subsystem according to claim 1, further comprising means for accessing and receiving the second completion report.