JPH0412494B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to an input/output system in which an input/output device is connected to a plurality of paths including an input/output control device to an access source such as a processor. The present invention relates to a diagnostic method for a memory that holds path control information for dynamic path selection to connect an input/output control device using a vacant path.

[Technology background]

Input/output devices are connected in order for the processor to perform desired processing. Among input/output devices, especially those requiring mechanical operation such as magnetic disk devices, an input/output control device is provided to control the input/output device in the channel of the processor, and the input/output device is controlled via the input/output control device. ing.

These input/output control devices and input/output devices are connected to form an input/output system, but if multiple input/output devices are connected, one input/output device is the input/output control device. While combining with
An I/O controller cannot access other I/O devices. Therefore, even during mechanical operations of input/output devices that do not require control by the input/output control device, the input/output control device is occupied, making it impossible to access other input/output devices.
In the case of a DASD (Direct Access Storage Device), the processor is kept waiting for a long time. For this reason, input/output systems having an input/output device open control function and a dynamic path selection function have been developed.

[Prior art and problems]

In such an input/output system having a dynamic path selection function, each input/output device is connected to each of a plurality of paths including the input/output control device to the processor which is the access source, and the input/output device is connected to each of a plurality of paths including the input/output control device, and it is possible to select any one of the paths. ,
It is configured so that it can be connected to the input/output control device of that path. After one input/output control device connects and starts up the input/output devices, the input/output device is disconnected to perform mechanical operation, and at the same time, that input/output control device can start up other input/output devices.
Furthermore, after the input/output device completes its mechanical operation, it utilizes a vacant path to reconnect with the input/output control device on that path to exchange data. In this way, after activation, the I/O control device of a free path is reconnected, so the I/O control device of the activated path may be reconnected to the I/O control device of another path, and for this reason, when disconnected, Path control information must be stored in memory.

This memory holds path control information necessary for control at the time of recombination, and if the contents are not correct, recombination control will not proceed smoothly, and therefore the dynamic path selection function will not be performed. become unable.

Conventionally, such memory abnormalities were not checked and were only indirectly detected as operational errors during actual recombination.

For this reason, the error cannot be detected unless the recombination control is performed, so there is a problem in that the error cannot be detected in advance and the recombination control is repeated unnecessarily.

[Purpose of the invention]

An object of the present invention is to provide a memory diagnosis method for an input/output system that can detect abnormalities due to failures in a memory provided for such a dynamic path selection function at an early stage and take immediate countermeasures.

[Structure of the invention]

Therefore, the present invention provides a plurality of paths connected to a common access source and each including an input/output control unit, an input/output device connected to each of the plurality of paths, and an input/output device for exclusive control and recombination control. It has a memory that holds path control information, receives an access request from the access source, refers to the path control information in the memory, confirms that the input/output device to be accessed is not in use, and then processes the input/output device. The control unit starts up the input/output device, connects it to one path, releases the occupation of the path, writes path control information to the memory, and uses the readiness signal of the input/output device to read the memory. An input/output system having a dynamic path selection function that refers to path control information, performs data transfer by recombining with a vacant path, and erases the corresponding path control information in the memory upon completion of the transfer, A diagnostic circuit for the memory is provided, and at least during control of the input/output device, the diagnostic circuit detects that each of the input/output control units of the plurality of paths is not accessing the memory. It is characterized by performing a normality check.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 is a block diagram of an input/output system with dynamic path selection according to the present invention, showing the DASD subsystem.

In the figure, 1 is a processor (access source),
It accesses the input/output system to process data, and has two channel sections 1a and 1b.DKC is a magnetic disk (input/output)
2 and 4 are control units (hereinafter referred to as directors) that constitute the control unit of the magnetic disk control unit and are connected to the channel units 1a and 1b of the processor 1, respectively. A device that receives access requests from units 1a and 1b, performs desired processing, and exchanges data. Reference numerals 3 and 5 denote adapters, each of which is composed of an adapter control section 30, 50 and a memory 31, 51, and the adapter control section 30, 50 is connected to the director 2,
4, and selectively sends it to the memory 31, 51 or a magnetic disk to be described later, and performs serial-to-parallel conversion; the memory 31, 5
1 stores path control information.

60, 61...6n are magnetic disks (devices), which are respectively connected to adapters 3 and 5 via cables to be described later.
and 7 and 8 are first and second cables, which connect each magnetic disk 60, 61...6n to 2
Control lines 9a and 9b are connected to each of the two magnetic disk control devices DKC, and are used by each magnetic disk 60, 61...6n to notify control signals (interrupt signals) to each magnetic disk control device DKC. It is.

In this way, in an input/output system with a dynamic path selection function, for access sources such as processors,
Each magnetic disk (input/output device) 60 to 6n is a magnetic disk control device (input/output control device) DKC.
The magnetic disk controller DKC of each path controls the magnetic disk according to instructions from processor 1, which is the access source. I'm doing it like that.

Next, the dynamic path selection operation of the embodiment configuration of FIG. 1 will be explained with reference to the operation explanatory diagram of FIG. 2 and the time chart of FIG. 3.

When the processor 1 accesses the magnetic disk, the processor 1 issues an access request (read/write, command address) to the director 2 (or 4) from the channel section 1a (or 1b). To access the magnetic disk 60, the director 2 connects the memories 31 and 5 via the adapter 3.
1 and determines whether the magnetic disk 60 is in use. If not, the director 2 gives a start command to the magnetic disk 60 via the adapter 3 and connects it to the magnetic disk 60 via the cable 7. (Figure 2A).

As a result, the director 2 transfers the read/write command, track, and cylinder address to the magnetic disk 60.

Upon receiving a response signal from the magnetic disk 60 upon completion of this transfer, the director 2 receives a response signal from the memory 3.
1 and 51 via the adapter 3, write path group information (the group name of the path used) and device-specific information (access status, device address, track, cylinder address, etc.), stop controlling the magnetic disk 60, and Release the possession of the object and separate it (Fig. 2C). The magnetic disk 60 starts a head seek operation based on the above-described given command and address.

Next, when the seek operation of the magnetic disk 60 is completed, a ready signal is given to the adapters 3 and 5 via the control lines 9a and 9b. At this time, assuming that the first path of the director 2, adapter 3, and cable 7 is being combined with another magnetic disk, and the second path of the director 4, adapter 5, and cable 8 is empty, this completion signal is accepted by the director 4. At this time, the director 4 reads the path group information from the memory 51, and confirms that the first path connected in the step is in the same group as its second path, that is, the same processor 1.
The director 4 confirms that it is the one for the second
Figure D).

As a result, the director 4 and the magnetic disk 6
Data is transferred between 0 and 0, and data is read from or written to the magnetic disk 60.

When the data transfer is completed, the director 4 erases the contents of the memories 31 and 51 corresponding to the magnetic disk 60 via the adapter 5.

Meanwhile, inside the step, there is a magnetic disk 6.
When access to 0 occurs, for example, via the channel section 1b, the director 4 reads the contents of the memories 31 and 51 via the adapter 5, confirms that the magnetic disk 60 is in use, and prevents the access from occurring. Permission is returned to the channel unit 1b to prevent conflicting activation.Conversely, when access to the magnetic disk 61 occurs via the channel unit 1 as shown in FIG. 2B, the director 4 accesses the memory 31, It is confirmed from the contents of 51 that it is not in use, and the magnetic disk 61 is connected to the director 4 via the adapter 5 and cable 8, and simultaneous operations are performed.

In this way, the memories 31 and 51 store path control information used for exclusive control to prevent contention and for connection control at the time of recombination.

This is shown in a time chart as shown in FIG. 3, and the memories 31 and 51 are not accessed except during startup, disconnection, completion, and termination.

Therefore, in the present invention, the memory is diagnosed using such free time to ensure the normality of the memory.

FIG. 4 is a block diagram of an embodiment of the present invention.
2 shows details of the adapter 3 (or 5) in FIG. 1. FIG.

In the figure, the same parts as in FIG. 1 are indicated by the same symbols, and 31a is an address register for setting the address of memory 31;
b is a data register for setting data read out from the memory 31; 32 is a control circuit which accesses the memory 31 and reads data from the memory 31 according to instructions from the adapter control section 30; 33 is a tie breaker that reads and controls the memories 31 and 51 in a time-sharing manner; 34 is a diagnostic circuit that reads and controls the memory 31 and 51 in response to diagnostic commands from the adapter controller 30; A comparator circuit 35 gives a read command to the memories 31 and 51 to read and diagnose the contents of the memories 31 and 51, and a comparison circuit 35 compares the read data sent from the memory 51 of the adapter 5 via the data bus with the data of the memory 31. It compares the read data and notifies the diagnostic circuit 34 of the comparison result.

Next, the operation of the embodiment shown in FIG. 4 will be explained.

(a) The adapter control unit 30 uses idle time, that is, data transfer periods A and C after path connection (and period B when not connected to another input/output device during seek)
A diagnostic command is then given to the diagnostic circuit 34.

(b) The diagnostic circuit 34 detects by the tie breaker 33 that the adapter 5 is not using the memories 31 and 51, and connects the memory 3 via the address bus.
The memory address to be checked is given to 1 and 51, and set in the address register 31a and the address register (not shown) of the memory 51.
At the same time, a read command is given to the memories 31 and 51, the contents of the corresponding address of the memory 31 are read to the data register 31b, and the memory 51 is similarly given a read command.
The contents of are set in a data register (not shown).

(c) The comparison circuit 35 compares the contents of the data register 31b with the memory 51 sent via the data bus.
and notifies the diagnostic circuit 34 of the comparison result.

(d) On the other hand, the contents of the data register 31b are given to the diagnostic circuit 34, where a parity check is performed.

(e) In this way, the diagnostic circuit 34
1, the contents of both memories 31 and 51 are collated, and the read data is parity checked.
51, and when an error is detected, this is notified to the adapter control unit 30.

(f) The adapter control unit 30 reports this error notification to the director 2, and performs appropriate recovery processing.

Similarly, the adapter 5 has the same configuration and performs the same diagnostic operation when the memory of the adapter 3 is not used.

On the other hand, normal writing/reading to and from the memories 31 and 51 is performed by the control circuit 32, and the control circuit 32 gives a write command to the memories 31 and 51 based on a write command given from the director 2 via the adapter control unit 30. , and sends the address to the address register 31a (and memory 51) via the address bus.
address register) and pass control information to both memories 31 and 51 via a data bus (not shown).
and write the path control information in the memories 31 and 35. Further, when a read command is given from the director 2, the control circuit 32 gives the read command to the memories 31 and 51 and gives an address via the address bus.
The control circuit 32 receives read data from the memory from each data register 31b, and the control circuit 32
0 to director 2.

In the above explanation, the memory for storing path control information is provided in both adapters 3 and 5, but it may also be provided in directors 2 and 4. Also, if both magnetic disk control devices can access it, one memory is provided. It may also be configured with memory.

Although the present invention has been described above using one embodiment, the present invention can be modified in various ways according to the gist of the present invention, and these are not excluded from the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, the following effects are achieved.

The memory that holds the path control information necessary to perform exclusive control and recombination control for dynamic path selection is diagnosed using free time while controlling input/output devices, so memory failures can be detected early. can be detected.

Utilizing free time while controlling input/output devices,
Since the memory is diagnosed, memory failures can be detected before recombination control, and unnecessary recombination control due to memory failures can be prevented.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an input/output system having a dynamic path selection function according to the present invention, FIG. 2 is an explanatory diagram of the dynamic path selection operation according to the configuration shown in FIG. 1, FIG. 3 is a time chart thereof, and FIG. 4 1 is a block diagram of a main part of an embodiment of the present invention. In the figure, DKC...magnetic disk control device (input/output control device), 60-6n...magnetic disk (input/output device), 7, 8... cable, 31, 51...
...Memory, 34...Diagnostic circuit.

Claims (1)

[Claims] 1. A plurality of paths connected to a common access source and each including an input/output control unit, an input/output device connected to each of the plurality of paths, and a plurality of paths for exclusive control and recombination control. It has a memory that holds path control information, receives an access request from the access source, refers to the path control information in the memory, confirms that the input/output device to be accessed is not in use, and then processes the input/output device. The control unit starts up the input/output device, connects it to one path, releases the occupation of the path, writes path control information to the memory, and uses the readiness signal of the input/output device to release the memory. An input/output system having a dynamic path selection function that refers to path control information, performs data transfer by recombining with a vacant path, and erases the corresponding path control information in the memory upon completion of the transfer, A diagnostic circuit for the memory is provided, and at least during control of the input/output device, the diagnostic circuit detects that each of the input/output control units of the plurality of paths is not accessing the memory. A memory diagnostic method for an input/output system characterized by performing a normality check.