JPH0546288A - Power source backup stoppage control system - Google Patents

Abstract

PURPOSE:To surely execute an I/O instruction that remains in a controller. CONSTITUTION:A system in which the stoppage of power source backup to devices behind the controller 2 is informed to the controller 2 which holds error information from the device 3 provided with a queuing table 5 and is also connected to a low-order device when power failure occurs and which generates sense pending as holding the execution of the I/O instruction, and disconnects the power source for backup after the lapse of constant time is comprised by providing a sense pending clear part 6 in the controller 2, and in such a way that the controller 2 receiving such notice from the channel clears the sense pending first by operating the sense pending clear part 6, and surely executes the I/O instruction that remains in the queuing table 5 by the power source for backup is disconnected after the lapse of constant time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power backup stop control system, and in particular, a CPU that recognizes the occurrence of a power failure notifies a channel of prohibition of subsequent instruction issuance from the channel to the control device, and The channel has a queuing table for storing I / O commands, and when it receives error information from a device connected to a lower level, it holds the error information to perform sense pending while holding execution of the I / O command. The present invention relates to a power supply backup stop control method in which a power supply backup stop below the control device is notified to a control device that occurs and the backup power supply is cut off after a certain period of time.

Generally, channels, controllers and DASDs
In an I / O system consisting of devices such as (Direct Access Storage Device), I / O commands from channels are stored in a queuing table provided in the control device and executed sequentially. It is required to operate the backup power supply until the execution of the I / O command remaining in the queuing table is completed, and the present invention is a power supply backup stop control method for responding to such a request.

[0003]

2. Description of the Related Art A conventional I equipped with a backup power source
The outline of the / O system is shown in Fig. 4.
Is a power failure detection unit and power backup mechanism, 52 is a CP
U and 53 are control devices, 54 is a device such as DASD, 55 is a power supply control signal transmitting section, 56 is a channel, and 57 is a queuing table.

Here, the state from the start of the power supply backup to the disconnection of the backup power supply to the control device is as shown in FIG. That is, when a power failure occurs at time t ₀ , the power failure sensing unit 51 detects this and notifies the CPU 52, and the power supply backup mechanism 51 operates. Upon receiving the power failure notification, the CPU 52 notifies the application of the power failure at time t ₁ after a fixed time (about 15 seconds). The application that recognizes the occurrence of a power outage performs program processing for responding to a power outage for a fixed time (about 50 seconds)
After the execution, at time t ₂ , the channel 56 is notified of the prohibition of subsequent instruction issuance, and the power supply for backup from the power supply backup mechanism 51 to the CPU is cut off. Channel 56 is at time t ₃ after a certain time (about 5 seconds),
After notifying the control device 53 of the power supply backup stop below the control device via the power supply control signal sending unit 55, the power supply for backup to the channel from the power supply backup mechanism 51 is cut off. The control device 53 that receives the notification of the power backup stop
At time t ₄ after performing the closing process for a predetermined time (after about 40 seconds), to disconnect the backup power to the control unit from the power-backup mechanism 51. Power backup is stopped by the following procedure.

Then, the queuing table 57 is set within the time (t _{3 to} t ₄ ) from when the control device 53 is notified of the power supply backup stop until the backup power supply to the control device is actually cut off. The I / O instruction that has been held is executed so that no unexecuted I / O instruction remains at time t ₄ .

[0006]

As described above, the control unit 53 in the conventional power supply backup stop control system tries to process the remaining I / O command within the time (t _{3 to} t ₄ ). When the error information is originally received from the lower device 54, sense pending occurs and the execution of the I / O instruction is suspended, so that, for example, as shown in FIG. 6, the power supply backup stop notification is received (time t ₃ ). If the sense pending occurs before that, the controller 53
However, there is a problem in that the backup power supply is cut off while the I / O command cannot be processed and remains.

Sense pending is a device
As a result of a unit check of 54 (for example, a check for a CRC error or an error in seek operation), the sense (error information) sent from the device 54 side is held in the control device 53 without being notified to the channel 56. It is in a state of being continued.

Therefore, in the present invention, the control device is provided with a sense pending clear unit, and when the power supply backup stop notification is received from the channel, the control device first operates the sense pending clear unit to clear the sense pending. This makes it possible to execute the I / O commands remaining in the control device at the stage of receiving the notification.

[0009]

According to the present invention, when a power supply backup stop notification is sent to a control device from a channel that recognizes the occurrence of a power failure, the control device clears sense pending, and then the power supply is turned off. The I / O commands remaining in the queuing table are executed within a fixed time until the backup power supply from the backup mechanism is cut off.

FIG. 1 illustrates the principle of the present invention. In the figure, reference numeral 1 denotes a CPU, which recognizes the occurrence of a power failure by a notification from a power failure detection unit, and the application starts power backup stop processing. Reference numeral 2 denotes a control device, which includes a queuing table and a sense pending clear unit, and is connected with a DASD or the like as a lower device. 3 is a device, which is composed of DASD or the like,
It operates based on I / O commands from the controller. Four
Is a channel, and the CPU handles input / output processing to / from the device
Has the ability to run independently from. A queuing table 5 is an I / O notified from the channel.
Contains instructions. 6 is a sense pending clear unit, which clears the sense pending of the control device,
It enables the execution of I / O commands remaining in the queuing table. Reference numeral 7 denotes a power supply backup mechanism, which supplies backup power supply to each of the CPU, control device, and device at the same time when a power failure occurs.

Here, the processing procedure from when the CPU recognizes the occurrence of the power failure to when the backup power source below the control device is turned off is as follows. That is, the CPU 1 recognizes the occurrence of a power failure by the notification from the power failure detection unit and proceeds to the next step. The application of CPU1 is
The prohibition of issuing a new command from the channel 4 to the control device 2 is notified, and the process proceeds to the next step. The channel 4 notifies the control device 2 that the power supply backup of the control device 2 and below is stopped, and proceeds to the next step and step. It is determined whether or not sense pending is occurring. If "YES", the process proceeds to the next step, and if "NO", the process proceeds to the step. The sense pending clear unit 6 clears the sense pending of the control device 2 and proceeds to the next step. The control device 2 executes the I / O instruction which is held in the queuing table 5. After a certain period of time, the power supply for backup from the power supply backup mechanism 7 to the control device 2 and the device 3 is cut off. Power supply backup stop processing is performed by the procedure described above.

[0012]

As described above, according to the present invention, as shown in FIG.
Sense pending occurs and cueing table 5
Even if the execution of the internal I / O command is suspended, if the power supply backup stop notification is received from channel 4,
Since the controller 2 first clears this sense pending by the sense pending clear unit 6, within a certain time (t _{3 to} t ₄ ) until the backup power source from the power source backup mechanism 7 to the controller 2 is actually cut off. In addition, it is possible to execute the I / O instruction which is held in the queuing table 5.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A control circuit used in the present invention will be described with reference to FIG. In the figure, 21 is SA (Service Adapte
r), 22 is RM (Resorce Manager), 23 is CA (Channel Adap)
ter), 24 is DA (Device Adapter), 25 is a service bus, 2
Reference numeral 6 indicates a common bus, CA 23 forms an interface with a channel, and DA 24 forms an interface with a device.

The SA21 having a maintenance / monitoring function is
Memory 3 for storing MPU31, programs and data
2. The RM22, which is composed of the power failure signal receiving unit 33 and the bus communication control unit 34 and has the management function of the entire control device,
It comprises a U41, a memory 42 for storing programs and data, bus communication control units 43, 44, a queuing table 5 for storing I / O commands, and a sense pending clear unit 6.

When a power backup stop command from the CPU side (below the control device) is notified to the power failure signal receiving section 33 by a channel instruction, the SA21 notifies the RM22 via the service bus 25. Then, RM22,
Check if sense pending is occurring,
In the case of “occurrence”, the sense pending clearing section 6 clears this sense pending and the I / O instructions remaining in the queuing table 5 are transferred to the common bus 26 and
It is sent to the device side via A24.

[0016]

According to the present invention, when a power failure occurs, the channel has a queuing table for storing I / O commands, and when an error information is received from a device connected to a lower level, this is held. In an input / output system that notifies a control device that generates sense pending while execution of the I / O command is suspended to stop power backup of the control device and below, and turns off the backup power after a certain time, Since the control device is provided with a sense pending clear unit, and when the controller receives a notification of stop of power backup from the channel, the control device first operates the sense pending clear unit to clear the sense pending. After surely ending the execution of the I / O command held in the control device at the stage of receiving the notification It is possible to perform cutting of Kkuappu power.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is an explanatory diagram showing a state from the start of the power supply backup to the disconnection of the backup power supply to the control device according to the present invention.

FIG. 3 is an explanatory diagram showing a control circuit used in the present invention.

FIG. 4 is an explanatory diagram showing an outline of a conventional I / O system including a backup power supply.

FIG. 5 is an explanatory diagram (No. 1) showing a state from the start of power supply backup to the disconnection of the backup power supply to the control device in the related art.

FIG. 6 is an explanatory diagram (part 2) showing a state from the start of power backup to the disconnection of backup power to the control device in the related art.

[Explanation of symbols]

 In FIG. 1, 1 ... CPU 2 ... Control device 3 ... Device (DASD) 4 ... Channel 5 ... Queuing table 6 ... Sense pending clear unit 7 ... Power backup mechanism

Claims (1)

[Claims] 1. A CPU recognizing the occurrence of a power failure notifies a channel of prohibition of subsequent instruction issuance from the channel to the control device, and subsequently, the channel displays a queuing table for storing I / O instructions. When a control device that holds error information from a device connected to the lower layer and holds the error information and generates sense pending while holding the execution of the I / O command is suspended, In a power supply backup stop control method in which a backup stop is notified and the backup power supply is turned off after a certain period of time, a sense pending clear unit is provided in the control device, and the power supply backup stop notification is received from the channel. The control device first operates the sense pending clear unit to operate the sense pending. Cleared, the up power supply for backup after a certain time is disconnected, power backup stop control method being characterized in that so as to perform the I / O instructions remaining in the queuing table.