JPH07104820B2 - Data transfer control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] In a device for controlling data transfer such as a channel processor, regarding detailed information storage when an exception or error occurs during data transfer, the detailed information is stored once in a transfer buffer. Use for indicating that the area is in use for each area used in one data transfer of the transfer buffer storage for the purpose of providing a means capable of storing detailed information without stopping the system. A medium flag and a freeze flag indicating that the contents are frozen are provided. When a data transfer request from the request source is accepted, an area for transfer buffer storage is allocated and the busy flag for the area is set. Means for turning on the state and freezing the transfer buffer area used for the corresponding data transfer when a prespecified exception condition or error occurs Configure by providing a means for the lugs in the ON state.

[Industrial field of use] The present invention causes an exception or error in data transfer in a device such as a channel processor (hereinafter also referred to as CHP) that centrally manages data transfer from a channel including an input / output device. In particular, the present invention relates to a control method that can hold detailed information about data transfer when an error or the like occurs without stopping the operation of the system.

[Prior Art] In a device that centrally manages data transfer such as CHP,
For example, detailed information on the data transfer is required to investigate a state that should be reported as an exception (hereinafter, also simply referred to as an exception) due to an address error or the like or a data error occurs. The detailed information mentioned here includes a memory access type, a memory address, an access key, a byte mark, a channel address, and the like. When the data transfer is executed in the CHP, the detailed information is temporarily stored in the transfer buffer (hereinafter also simply referred to as the transfer buffer). Then, when an exception or error occurs, this information is needed to investigate the cause.

In the conventional data transfer control method, the transfer buffer storage area (hereinafter also referred to as an area) is provided corresponding to the channel address, so that a certain area is used when transferring data from the same channel. On the other hand, when an exception or error occurs, MS access is performed to report exceptions from the channel to the software (CSW store). At this time, the CSW information is sent via buffer storage, so the contents of the corresponding area remain. Absent. For this reason, there is a mode to save the operation contents by stopping the entire CHP or the entire system when an exception or error occurs for the operation test.

[Problems to be Solved by the Invention] As described above, in the conventional method, in the normal operation state, when an exception or an error occurs, the CSW information is transmitted via the buffer storage for reporting from the channel to the software. Since the data is transferred to the main memory (MS), the detailed information relating to the exception and error occurrence in the corresponding area in the buffer memory is erased, and there is a problem that the cause cannot be searched for.

On the other hand, in order to secure such information, when the system is set to the operation test mode, it is necessary to temporarily stop the operation of the CHP or the system, which causes a problem that the operation of the system is interrupted.

In view of such conventional problems, the present invention, when a data error, an exception, or the like occurs, detailed information about the data error, the exception, or the like is stored in a corresponding area of the buffer storage without stopping the operation of the system. The purpose is to provide a control method that can be stored in the storage.

[Means for Solving the Problems] According to the present invention, the above-mentioned objects are achieved by the means described in the claims. That is, according to the present invention, in a device that controls data transfer by receiving data transfer requests from a plurality of request sources via the transfer buffer storage, for each area used in one data transfer of the transfer buffer storage,
A busy flag indicating that the area is in use,
A means for providing a freeze flag indicating that the contents are frozen and allocating an area of the transfer buffer storage and turning on the busy flag of the area when a data transfer request from the request source is accepted And a state in which the freeze flag of the area of the transfer buffer used for the corresponding data transfer is turned on when a prespecified exception state or error occurs.

[Operation] FIG. 1 is a diagram for explaining the principle of the present invention, in which (a) shows an example of the relationship between the transfer buffer memory, the transfer control unit and each signal, and (b) shows the data transfer control. Of the control system of the department,
The example of the structure of the part relevant to this invention is shown.

In the figure, 1 is a data transfer control unit, 2 is a transfer buffer, 3 is an access control unit, 4 is an in-use flag, 5 is a freezing flag, and 6 and 7 are set / reset control units (abbreviated in the figure). S / R control), and 8 represents a register for setting the freeze mode.

In FIG. 7B, when the access control unit 3 receives the data transfer request, the access control unit 3 turns on the corresponding in-use flag of the area in which both the in-use flag 4 and the freezing flag 5 are turned off, and the area is used. To transfer data.
When the transfer is completed normally, the corresponding busy flag is turned off and the transfer result report is sent to the channel.

If an exception or the like occurs, it is sent to the channel as a transfer result report that it has been completed due to the exception. At the same time, if the exception matches the exception specified by the freeze mode, the freeze flag of the area used by the data transfer is turned on. The busy flag is turned off at the same time as the transfer result report is sent. Therefore, thereafter, the corresponding area of the transfer buffer is not used and is stored.

[Embodiment] FIG. 2 is a block diagram of an embodiment of the present invention, in which 9 is an access control unit, 10 is a busy flag, 11 is a freeze flag, and 12 and 13 are set / reset control units ( In the figure, it is described as S / R control by abbreviation) 14 is a freeze counter, and 15 is a register for setting a freeze mode.

The basic operation in the figure is the same as that already described in the section [Operation]. That is, in the figure, when the access control unit 9 receives a data transfer request, the access control unit 9 turns on the corresponding in-use flag of the area in which both the in-use flag 10 and the in-freeze flag 11 are turned off, and the area is used. To transfer data. When the transfer is completed normally, the corresponding busy flag is turned off and the transfer result report is sent to the channel.

If an exception or the like occurs, it is sent to the channel as a transfer result report that it has been completed due to the exception. At the same time, if the exception matches the exception specified by the freeze mode, the freeze flag of the area used by the data transfer is turned on. The busy flag is turned off at the same time as the transfer result report is sent. Therefore, thereafter, the corresponding area of the transfer buffer is not used and is stored.

In FIG. 2, the freeze counter 14 is added to the configuration of FIG. 1 shown above. Hereinafter, the reason why the freeze counter 14 is provided in this embodiment will be described.

If a large number of specified exceptions or the like occur in the contents of the freeze mode register 15, the area used for each transfer is frozen, and the usable area of the transfer buffer gradually decreases. The data transfer capacity is reduced in proportion to this, and the data transfer is completely stopped when there is no usable area. In order to prevent this, it is necessary to limit the frozen area so that it does not increase so much. In the present embodiment, such an event is controlled by the freeze counter 14. That is, the freeze counter 14 increments the freeze flag by 1 each time it is turned on. As a result, the freeze counter 14 indicates the number of freeze flags that are on. If the limit value of the freeze counter is also held during the freeze mode and the cause of the next freeze occurs when the freeze counter reaches the limit value, all previously set freeze flags are turned off, and finally Only the freeze flag due to the cause of occurrence is turned on. At the same time, the contents of the freeze counter 14 are set to "1".

FIG. 3 shows an example of the contents of the transfer buffer. In this example, one word is composed of 8 bytes and is composed of 5 words. In the same figure, a maximum of 32 bytes of data is stored in the 2nd to 5th words indicated by 17 _{1 to} 17 ₄ . The first word indicated by 16 stores the data transfer command code indicating the fetch / store type or the data length, the channel address, the access key, the byte mark and the memory address to be transferred. All of these are preserved when frozen. However, if an exception occurs during fetch access, fetch data may not be stored.

As described above, according to the present invention, when data transfer requests from a plurality of request sources are received via the transfer buffer storage,
In a data transfer control device such as CHP that controls data transfer, when a data error or an exception occurs, detailed information related to the data transfer can be stored without stopping the operation of the device or system.

In the case of a device such as the data transfer unit of CHP that cannot stop the entire operation even when an exception or error occurs, the processing content that was being executed at the time of occurrence is the only investigation material. According to the present invention, without stopping the operation of the CHP and the system as described above,
The contents of the processing in which the exception or error has occurred are saved, which greatly contributes to the investigation of the cause and the efficient operation of the system.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is a diagram showing an example of contents of a transfer buffer. 1 ... Data transfer control unit, 2 ... Transfer buffer, 3,9 ...
… Access control unit, 4,10 …… In-use flag, 5,11 …… Freezing flag, 6,7,12,13 …… Set / reset control unit,
8,15 …… Register to set freeze mode, 14 …… Freeze counter, 16,17 _{1 to} 17 ₄ …… Word of transfer buffer

Claims (1)

[Claims] 1. An apparatus for controlling data transfer upon receiving data transfer requests from a plurality of request sources via a transfer buffer storage, for each area used in one data transfer of the transfer buffer storage. A busy flag that indicates that the data is being used and a freeze flag that indicates that the contents are being frozen are provided, and when the data transfer request from the request source is accepted, the transfer buffer storage area is set. A means for allocating and turning on the in-use flag of the area, and turning on the freeze flag of the area of the transfer buffer used for the corresponding data transfer when a prespecified exception condition or error occurs. A data transfer control method, characterized in that a state for setting a state is provided.