JPH0234061B2 - SHUKIOKUAKUSESUSEIGYOHOSHIKI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling access to a main storage device of a computer system having a plurality of main storage devices and storage control devices.

In relatively large computer systems, as the capacity of the main storage area increases and the number of central processing units, channel processing units, etc. that request access to the main storage device increases, the main storage area is divided into multiple main storage devices. A system consists of a plurality of storage control devices each dedicated to one or more of these main storage devices, and the central processing unit, channel processing device, etc. are also connected to only one of these storage control devices. A configuration is adopted to allocate the data so that

In this case, the storage control devices are connected to each other by a transfer path for control information and data, and when each storage control device receives an access request to a main storage device that is not under its own control, it transfers the access request to the other storage control devices. Since the data is transferred to the storage control device for processing, there is a possibility that the access time will be delayed, so it is particularly desirable to efficiently control the storage control devices.

[Problems to be solved by conventional technology and invention]

FIG. 2 is a block diagram showing an example of the configuration of a computer system.

In this example, the main storage area is composed of four main storage units (MSU) 1a and 1b.
a, 1b are connected so as to be controlled by two individual storage control units (MCU) 2a, 2b.

Two central processing units (CPUs 3a, 3b and one channel processing unit (CHP) 4a, 4b) are connected to each storage control device 2a, 2b.

The storage control devices 2a and 2b are connected by a control line 5 to enable mutual communication.

For example, when a main memory access request is issued from one of the central processing units 3a, the storage control unit 2a accepts the request.

The storage control device 2a identifies whether the request is for the main storage device 1a or the main storage device 1b based on the storage address of the access request, and if it is an access request for the main storage device 1a, it internally handles the request. However, if the access request information is to the main storage device 1b, the access request information is sent to the storage control device 2.
b, and requests the storage control device 2b to process.

The storage control device 2b processes the access requests transferred from the storage control device 2a together with the access requests from the central processing device 3b etc. connected to itself in a predetermined priority order, and executes access to the main storage device 1b. Then, the execution result of the transferred access request is notified to the storage control device 2a.

When the main storage device 1a is accessed from the central processing unit 3b or the like, control similar to the above is required between the storage control device 2b and the storage control device 2a.

In such control, in order to maintain the order of access for each access requesting device and to manage the access priority among the access requesting devices, conventionally both storage control devices 2a and 2b perform their respective processing. Access requests were controlled by considering all access request devices in the system.

Furthermore, when transferring an access request to another storage control device, the request from the access requesting device must be held until the other device sends back a signal indicating completion of acceptance, which causes problems such as processing delays. It was hot.

[Means for solving problems]

The above problem arises in a computer system having a plurality of storage control devices connected to each other, and a main storage device and an access request device, each of which is connected to only one of the storage control devices. The control device has an access request storage unit consisting of a plurality of ports that holds access requests to the main storage device connected to the control device from the above-mentioned access request devices connected to other storage control devices, and Each storage control device has a status display unit that holds status information of the access request storage unit, and each storage control device receives an access request from the access request device connected to itself to a main storage device connected to another storage control device. is detected, one unused port is selected based on the status information held in the status display section and the access request information under predetermined conditions, and the access is made to the selected port. The problem is solved by the main memory access control scheme of the present invention configured to forward requests.

[Effect]

That is, the storage control device is provided with an access request storage section consisting of a port that holds access request information transferred from other storage control devices, and
It has a status display unit that holds status information of the access request storage units of other storage control devices.

In this way, when each storage control device transfers an access request to another, the storage control device sending the request refers to the status display section, determines an appropriate port, and specifies that port. and forward the access request.

In particular, unique processing priorities are assigned to the ports that constitute the access request storage section of each storage control device.
Referring to the status display section, if a port holds a preceding request from the same requesting device as the access request to be forwarded, select the free port with the highest priority among the ports with a lower priority than that port. ,
By selecting it as a transfer destination, it is possible to easily maintain the order of access requests issued from the same access request device.

[Embodiment] FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. The figure shows the storage control device 2a or 2b.
Since the configuration of one embodiment of one of the devices is shown and both storage control devices have the same configuration, in the following, unless otherwise specified, FIG.
This will be explained as showing the configuration of .

Access requests from the central processing unit 3a or the like connected to itself are received and held at each port 11 of the access request reception unit 10.

These access requests are input to the priority control unit 12 and the priority control unit 13, and it is first determined whether the access destination storage address of the request is the main storage device 1a connected to the storage control device 2a itself.

In the case of an access request to the main storage device 1a under its own control, it is processed by the priority control unit 12, and otherwise, it is processed by the priority control unit 13.

Further, access requests transferred from the other storage control device 2b as described below are held in each port 15 of the access request storage section 14, and received by the access request receiving section 10 by the priority control section 12. The access request is processed along with the requested access request.

When the priority control unit 13 detects an access request to be transferred to another storage control device based on the access destination storage address of the request, the priority control unit 13 refers to the information in the status display unit 16 and performs transfer processing of the access request.

The status display unit 16 includes display ports 17 for each port 15 of the access request storage unit 14 of the other storage control device 2b.

For each display port, when the priority control unit 13 determines the port 15 of the other storage control device 2b to which the access request is to be transferred, a busy indication and Set the request source device address of the access request to be transferred.

The contents set in the display port 17 are set in the storage control device 2b when the relevant access request is processed by the storage control device 2b of the transfer destination and an appropriate amount of time has elapsed since the access operation of the main storage device 1b was started. It is reset by a control signal sent to the control line 18 and input from the control line 19 of the other party storage control device 2a, and the corresponding display port 17 is displayed as being in an unused state.

By referring to the contents held in the status display section 16, the priority control section 13 first identifies whether the preceding request issued by the requestor of the access request being processed is still held.

If no access request from the same request source is held, the port 15 with the highest processing priority is selected from among the ports 15 corresponding to the display ports 17 that are displayed as unused.

In the access request storage unit 14, the port 15 is
For example, from port 15 on the top of the diagram to port 1 on the bottom
It is assumed that the priority order of processing is fixedly assigned in order from 5 to 5.

When port 15 is selected, access request information is transferred from control line 20 together with information specifying port 15 as a transfer destination. Also, the port 11 that received the transferred access request is reset to an empty state.

The control line 20 is connected to the control line 21 of the other storage control device 2b, and in the storage control device 2b, the port 15 specified by the specified information to be transferred is connected to the control line 21 of the other storage control device 2b.
Access request information is set in .

In the storage control device 2b, the priority control unit 12
refers to the access request to the main storage device 1b under its control from the access request reception unit 10 and the access request storage unit 14, based on the predetermined priority order and the state of the main storage device 1b according to the main storage status display 22. and executes access to the main storage device 1b according to the access request.

At the same time, the occupancy state of the occupancy unit of the main memory device 1b is set to the main memory state 22, and a required signal is input to the timing control section 23.

The timing control unit 23 measures the elapsed time from the start of access for each unit of occupancy of the main storage device 1b, and sends a message to the control line 24 at a predetermined elapsed time.
Outputs a signal specifying the reset port.

This signal is sent to the corresponding port 11 or 1 of the access request reception unit 10 and access request storage unit 14.
By resetting the ports 11 and 15, the ports 11 and 15 are made available to receive subsequent access requests.

At the same time, the signal on the control line 24 is also sent to the control line 18, and as mentioned above, the signal on the control line 24 is sent to the other storage control device 2.
The corresponding port 17 of the status display section 16 of a is reset.

At the elapsed time when the access operation of the main storage device 1b initiated by the access request is completed, a signal output from the timing control section 23 to the control line 25 causes the corresponding display on the main storage status display section 22 to change to: The display is reset to an unoccupied state.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a computer system in which access to a large-capacity main storage device is shared and controlled by a plurality of storage control devices, the control mechanism of the storage control device can be simplified and the control mechanism can be improved. It has a significant industrial effect of improving

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of an example of the configuration of a computer system. In the figure, 1a and 1b are main storage devices, 2a,
2b is a storage control device; 3a and 3b are central processing units; 4a and 4b are channel processing devices; 10 is an access request reception unit; 11 and 15 are ports;
3 is a priority control unit, 14 is an access request storage unit, 1
6 is a status display section, 17 is a display port, 22 is a main memory status display, and 23 is a timing control section.

Claims (1)

[Scope of Claims] 1. A computer system having a plurality of storage control devices connected to each other, and a main storage device and an access request device, each of which is connected to only one of the storage control devices, comprising: The storage control device includes an access request storage section 14 consisting of a plurality of ports 15 that holds access requests to the main storage device connected to itself from the above-mentioned access request devices connected to other storage control devices, and other storage control devices. It has a status display unit 16 that holds status information of the access request storage unit 14 of the storage control device, and each storage control device has a status display section 16 that retains status information of the access request storage section 14 of the storage control device, and each storage control device has a state display section 16 that maintains status information of the access request storage section 14 of the storage control device. When an access request to the storage device is detected, one unused port 15 is selected based on the status information held in the status display section 16 and the access request information under predetermined conditions. . A main memory access control method, characterized in that the method is configured to transfer the access request to the selected port 15. 2. The access request transferred to the port 15 is processed according to the priority order unique to the port 15, and the predetermined conditions include the previous access request device issuing the access request. When the access request is held in the access request storage unit 14, an unused port 15 having the lowest priority and the highest priority is selected from the port 15 holding the access request. 2. The main memory access control method according to claim 1, wherein the main memory access control method is configured to include a condition that