JP2004005727A - Input/output control unit, and input/output control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformly conduct service for input/output processing without being one-sided to a specified port, even when a speed is different in a channel bus between a channel and the input/output port. <P>SOLUTION: A frequency of a loop condition repeated with a busy response for start-up requirement and response for busy release (busy end) accompanied to finish of transfer in other input/output port is counted by a circulation number determining part 68 in either of the plurality of input/output ports A, B, as shown Fig.1(B), so as to determine whether the loop frequency exceeds a prescribed value or not. When the input/output port of which the loop frequency exceeds the prescribed value is determined by the circulation number determining part 68, a route control part 46 allocates reception for the start-up requirement with priority to the determined input/output port. That is, the control part 46 receives only the start-up requirement for the priority allocation input/output port, and responds with the busy response for the start-up requirement to the other inpu/output port. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an input / output control device for processing input / output requests by individually connecting a plurality of channel devices on a host computer to a plurality of input / output ports, and more particularly to an input / output control device using channel buses having different transfer speeds. The present invention relates to a device and an input / output control method.

FIG. 26 shows an example of an input / output subsystem using a magnetic tape device. The input / output subsystem includes a magnetic tape control unit 410 functioning as an input / output control unit and a plurality of magnetic tape drive units 412-1 to 412-4 functioning as input / output devices. Device unit numbers # 1 to # 4 are defined for the magnetic tape drive units 412-1 to 412-4.

The magnetic tape control unit 410 has, for example, two input / output ports 420-1 and 420-2. Port numbers A and B are defined for the input / output ports 420-1 and 420-2. Channel devices 416-1 and 416-2 of the host computers 414-1 and 414-2 are connected to the input / output ports 420-1 and 420-2 via channel buses 418-1 and 418-2. Channel numbers A and B are defined for the channel devices 416-1 and 416-2. In the following description, channels A and B and ports A and B are simply referred to.

入 出力 I / O operations by the host computer will be briefly described. For example, it is assumed that an input / output request, for example, a write request for the magnetic tape loaded into the magnetic tape drive unit 412-1 by the host computer 414-1 occurs. The channel A of the host computer 414-1 issues a start I / O request (start request) to the input / output port A, specifying the device number # 1 of the magnetic tape drive unit 412-1.

The magnetic tape control unit 410 checks whether the port B is being connected to the channel B in response to the start I / O request from the port A. If the port B is not in the coupled state, it accepts the start I / O request for the port A, connects to the channel A, responds that the start I / O request has been normally completed, and performs command sequence transfer processing. On the other hand, when the start I / O request from the channel A is received at the port A and the channel B is being connected, a busy response is returned. When the transfer processing by the connection between the channel B and the port B is completed, a unit end status response is sent from the port B to the channel B, and the connection is disconnected. Along with this, a busy end indicating that the busy is released is also performed from the port A to the channel A, and an activation request is made to the port A again from the channel A in the waiting state by the busy response.
Japanese Patent Application Laid-Open No. 05-197651

In an input / output control device that processes input / output requests from a plurality of channels, it is necessary to provide services to some extent evenly with respect to input / output requests of each channel. However, if the transfer speed of the channel bus is different, or if different transfer protocols are adopted depending on the channel, such as an electric channel bus or an optical channel bus, the service tends to be biased toward high-speed channels, and services for low-speed channels are inevitable. There was a problem of lowering.

Furthermore, as a system environment, high-speed host computers and medium- and low-speed host computers are often mixed, and the high-speed host computers and medium- and low-speed host computers are connected so as to be capable of cross-calling. In such a case, a similar problem occurs.

This will be described below with reference to FIG. For example, assume that channel A is a low-speed channel and channel B is a high-speed channel. The input / output control in this case is as shown in a time chart of FIG. 27, for example.

Now, a start I / O request 500 is sent from the high-speed channel B to the port B, and when a coupling completion response 502 due to normal termination is obtained, the command sequence transfer processing 504 and 506 between the high-speed channel B and the port B is performed.

If it is assumed that the start I / O request 508 is issued from the low-speed channel A to the port A during the transfer processes 504 and 506, the busy response 510 is returned because the port B is being connected.

(4) When the transfer process 506 is completed, a unit end (Unit End) 512 is returned from the port B to the high-speed channel B, and the connection is released. Along with this unit end 512, a busy end 514 indicating the busy release is returned from the port A to the low-speed channel A waiting for the busy release. If the next input / output request has occurred on the high-speed channel B having received the unit end 512, a start I / O request 516 as a start request is immediately issued from the high-speed channel B to the port B, and a connection completion response 518 Then, the process again enters the transfer processes 520 and 522.

On the other hand, the low-speed channel A that has received the busy end 514 recognizes the release of the busy and issues a start I / O request 524 to the port A. However, it takes time from issuing the busy end 514 to receiving the start I / O request 524 at the port A. During this time, the port B is being connected by the start I / O request 516 from the high-speed channel B. I have. Therefore, in response to the start I / O request 524 from the low-speed channel A, a busy response 526 is issued again from the port A, and the low-speed channel A again waits for the busy release.

Therefore, as long as the input / output request continues to the high-speed channel B, the low-speed channel A repeats the start I / O request, the busy response, and the busy-end loop processing, and the input / output request is not accepted, and the service is deteriorated. In the worst case, there is a problem that the host computer of the low-speed channel A is in a check condition in which it is determined that some abnormality has occurred in the channel device or the input / output subsystem due to the long-time loop processing. .

In addition, depending on the control method, when input / output requests from the high-speed channel are continuous, there is no time to respond to the low-speed channel A with a busy end associated with the end of the coupling on the high-speed channel, and the low-speed channel waiting for the busy release is not used. No matter how long it waits, the busy end is not obtained, and the busy release wait times out and the low-speed channel I / O request ends in an error.

As a method of solving the problem that the service of the input / output control device is biased to a specific channel, there is a method of changing the priority of a route in a time-sharing manner so that each input / output port is equally serviced. .

FIG. 28 shows a case where eight channels of ports A to H are provided in the input / output control device, and priorities are sequentially assigned to ports A to H by a clock. For example, when there is a start request to all the input / output ports A to H at time t0, the clock is present in the slot of the input / output port C and the priority is set, and the connection at the input / output port C is accepted. You. For other input / output ports, a busy response is automatically reported.

Assuming that there is a start request to two of the input / output ports B and E at the time t0, the coupling of the input / output port E is accepted at the time t1 when the clock is changed to the slot of the input / output port E. Automatically reports a busy response.

The method of changing the priority of the route by the time division is effective when the channel buses have the same performance and the protocol such as the electric channel bus or the optical channel bus is the same. However, it is not very effective when the transfer speed is different or the protocol in which the electric channel and the optical channel are mixed is different.

An object of the present invention is to provide an input / output control device and a control method capable of uniformly providing input / output processing without biasing to a specific port even if the channel bus speed between a channel and an input / output port is different.

FIGS. 1 and 2 are explanatory diagrams of the principle of the present invention.

First, the present invention is directed to an input / output control device in which a plurality of channel devices on the host device side and a plurality of input / output ports are connected via channel buses having different transfer speeds. More specifically, the present invention is applied to an input / output control device having a high-speed input / output port and a low-speed input / output port connected to each of a high-speed channel device and a low-speed channel device on the host device side via channel buses having different transfer speeds. .

According to the present invention, as shown in FIG. 1 (A), each of the input / output ports A and B in the input / output control device 10 responds from the response of the busy release with the completion of the transfer of the other input / output port to the reception of the activation request. And a start-up time measurement storage unit 48 for measuring and storing the start-up time. When the route control unit 46 receives a start request from the high-speed channel device B to the high-speed input / output port B, the low-speed input / output is performed over the start-up time T2 of the low-speed input / output port B stored in the start-up time measurement storage unit 48. Wait for a start request for port B. If there is an activation request to the low-speed input / output port B during this waiting time, the low-speed input / output port B is connected to the corresponding low-speed channel device B to perform the transfer processing.

In this case, the busy response is made to the high-speed channel device A. If there is no activation request from the low-speed input / output port B during the waiting time, the high-speed channel device A and the high-speed input / output port A are connected to perform a transfer process.

The present invention further includes a busy ratio measurement storage unit 50 that measures and records the busy ratio of each input / output port. In this case, the start-up time measurement storage unit 50 generates and stores the maximum time Tmax, the average time Tav, and the minimum time Tmin every time the start-up times T1 and T2 of each of the input / output ports A and B are measured. The route control unit 46 selects the maximum time, the average time, or the minimum time so that the busy ratios R1 and R2 of the input / output ports A and B stored in the busy ratio measurement storage unit 50 are equal, and performs low-speed input. A waiting time T1 for a start request of the output port B is set.

The busy ratio R is calculated by dividing the number of busy responses measured for each of the input / output ports A and B by the number of input / output activations from the channel device. If the busy rate R1 of the low-speed input / output port A is larger than the busy rate R2 of the high-speed input / output port B, the wait time is set based on the busy rate. If the busy rate R1 is equal to the busy rate R2 of the high-speed input / output port B, the average time Tav is selected and set. If the busy rate R1 of the low-speed input / output port A is smaller than the busy rate R2 of the high-speed input / output port B, the minimum time Tmin is selected and set.

The following is a modification of the above invention. First, the input / output control device is provided with a start-up time measuring unit that measures the start-up time from when the low-speed input / output port A responds to the low-speed channel device A to the low-speed channel device A until the start request is received. The route control unit 46 causes the processing request from the high-speed channel device B to the high-speed input / output port B to wait for the measured startup time when responding to the busy release from the low-speed input / output port A. A request for processing from B is received from the low-speed channel device B.

A waiting time setting unit that varies the waiting time of the route control unit 46 based on the measurement time of the activation time measuring unit may be provided. Further, a waiting time setting unit for setting the waiting time of the route control unit 46 by an input operation of the operator may be provided.

Further, according to the present invention, as shown in FIG. 1 (B), the determination unit 68 allows one of the plurality of input / output ports A and B to respond to the start request with a busy response and to cancel the busy associated with the completion of the transfer of the other input / output port. The number of loop states in which the response (busy end) is repeated is counted, and it is determined whether or not the number of loops exceeds a predetermined value.

When the determination unit 68 determines an input / output port whose loop count exceeds a predetermined value, the route control unit 46 preferentially allocates the reception of the activation request to the determined input / output port. That is, the route control unit 46 accepts only a start request for a priority-assigned input / output port, and makes a busy response to a start request for another input / output port.

According to the present invention, as shown in FIG. 1C, the busy response time storage unit 70 stores, for each of the plurality of input / output ports A and B, the time at which a busy response to the activation request is made. The processing port determination unit 72 determines the input / output port having the oldest response time among the busy response times as the processing port every time the transfer processing for the activation request ends. The route control unit 46 preferentially allocates the start request to the determined input / output port.

Further, according to the present invention, as shown in FIG. 2D, during the connection of a specific channel device B and an input / output port B by the route control unit 46, a start request from another channel device A to another input / output port A is provided. If there is, the retry interrupt processing unit 74 responds the retry status from the other input / output port B and disconnects the connection with the other channel device B. When the connection between the input / output port A and the channel device A that is currently being processed is completed, the trial interrupt processing unit 74 notifies another channel device A of a retry start interrupt notification from the other input / output port A and starts up. Let the request be retried.

Further, according to the present invention, as shown in FIG. 2E, when a predetermined interrupt condition is satisfied during the connection between the specific channel device B and the input / output port B by the route control unit 46, for example, the interrupt timer 80 is activated. When the time is up, the retry interrupt processing unit 76 performs an interrupt process. This retry interrupt processing is
(1) Processing is interrupted by responding the retry status from the input / output port B to the channel device B to disconnect the connection.

(2) When the disconnection is completed, the busy response status of all ports A and B is checked, and the priority processing port is determined. For example, the port A to which the busy response has been made before is determined as the priority processing port.

{(3) Subsequently, the priority processing port A responds the end status to the channel device A to make a request for activation.

(4) When the transfer process associated with this activation request is completed, the retry interrupt processing unit 76 notifies the channel device B of the retry start interrupt from the input / output port B, and restarts the interrupted process.

Here, the retry interrupt condition is
1) The coupling time of the input / output port has reached a certain time,
2) the number of command processing of the input / output port during coupling has reached a predetermined value,
3) that the busy rate reaches a predetermined value in a busy response to a start request to another input / output port during the connection of the input / output port;
And so on.

In the present invention, as shown in FIG. 2 (F), command analysis execution units 92 and 94 are provided for each of the plurality of input / output ports A and B. For example, the command analysis execution unit 92 analyzes whether the command received in response to the activation request of the input / output port A is an executable command while the other input / output port B is connected, and if the command is executable, It receives a start request and executes command processing for internal resources.

Specifically, when data transfer of internal resources is performed by coupling with another input / output port B, if another internal resource is a control command that does not involve data transfer, activation of input / output port A is started. Accepts the request and executes command processing for other internal resources.

The internal resources are a plurality of input / output devices having a control bus independent of the data bus, for example, the magnetic tape drive unit 12.

According to the input / output control device and method of the present invention, the following operations can be obtained.

The present invention can be called a learning method. One reason that the input / output control service is biased to high-speed channel devices is to increase the speed from when a busy release waiting channel receives a busy release notification (busy end) to when it issues an activation request. Generally, this time is short for high-speed channels and long for low-speed channels.

Therefore, a timer is provided for each input / output port to dynamically measure and store the start-up time from responding to the busy release to receiving the start-up request. The measurement result of the activation time is calculated and stored separately for the maximum value, the minimum value, and the average value. For example, even if a start request is continuously received after a unit end at a high-speed input / output port, the input / output controller waits for a start request of a low-speed port for the start time without immediately performing an acceptance response. Then, when activation from the low-speed input / output port comes, it is determined which of the high-speed port and the low-speed port is accepted, and the service is prevented from being biased to only one side.

ビ We use the busy rate as one of the indicators of service bias. The busy rate is obtained by dividing the number of busy responses obtained by the busy response counter by the value of the number-of-starts counter that accumulates the number of starts from the channel. Then, the waiting time is determined so that the busy ratio of each input / output port is made as small as possible and the difference between the busy ratio values of each input / output port is not increased.

For example, if the busy rate of the responded I / O port is high after the response to the busy release, the system waits at a value near the maximum value of the start-up time, and conversely, the busy rate of the I / O port is low and the busy of the other I / O port If the rate is high, wait at a value near the minimum. As described above, according to the present invention, the service of each channel can be made uniform by its own learning.

Further, according to the present invention, if the loop processing of the busy response and the busy release response (busy end) continues for a long time, a check condition occurs on the host side, which is prevented. In other words, the counter detects the number of times of the loop processing, which becomes a start request, a busy response and a busy release response, and preferentially services an input / output port whose counter exceeds a certain value. Respond busy to other input / output ports. After the priority processing is completed at the input / output port, the counter of the input / output port is reset. As a result, a check condition caused by a loop between the busy response and the busy release response can be avoided.

Furthermore, the present invention is a time series processing method. The time of busy response to each I / O port is stored, and when the processing with the ongoing channel is completed, the busy response time of each I / O port is checked, and the busy end is reported to the I / O port indicating the oldest time Service with priority.

{Furthermore, the present invention is a retry interruption method. If activation from another channel occurs during the connection with the channel, a status requesting the channel to be retried is reported instead of the busy response, and the connection with the later activated channel is temporarily disconnected. When the connection with the channel currently being processed is completed, a retry start interrupt is issued to the channel for which the retry request has already been made, and the channels are reconnected. As described above, by responding the retry status instead of the busy response, the input / output control device can determine which input / output port is to be re-coupled, and each input / output port can be serviced on average.

{Furthermore, the present invention is a modification of the retry interruption method. First, when a predetermined interrupt condition (predetermined time, predetermined command processing count, predetermined busy rate, etc.) is satisfied during connection with the channel, an interrupt is generated and the status of the channel retry request is sent to the currently connected channel. Responds, interrupts processing, and temporarily disconnects. Thereafter, for all the buses, whether a busy response has been previously made or not, a check factor analyzes an interrupt factor to determine which I / O port to service.

(4) After the processing port is determined, the unit end is returned from the port and processing is performed with priority. After this priority processing is completed, an interrupt notification of retry start is sent to the channel that has made a status response to the retry request, and the interrupted processing is resumed by reconnection. As a result, it is possible to avoid a situation where the processing of the high-speed channel is continued and the unit end for releasing the busy response in the low-speed channel cannot be reported.

Furthermore, the present invention is an intelligent input / output port functioning as a channel switch. Even if the command is being processed by another I / O port, it is determined whether the command received by the I / O port itself can be executed. If the command can be executed, the process is executed for the lower drive unit and the number of busy responses Reduce.

For example, if a start request is issued to a certain input / output port while another input / output port is being connected, the request is accepted and the command is analyzed. In the case of a non-existent command, for example, a control command of a motion system or a sense system, the command is effectively accepted and executed. This intelligent function is effective when the data bus and the command processing bus are separate, or even if the common bus has hardware with a common bus configuration that can perform data transfer and data transfer for command processing at the same time. It becomes.

As described above, according to the present invention, even if a plurality of input / output ports of the input / output control device are connected to the channel device on the host computer side by channel buses having different transfer speeds, the service for the input / output request can be provided. It is possible to reliably prevent a bias between a specific channel and a port, and to provide services to each input / output port almost uniformly even if input / output requests from channel devices overlap.

Therefore, it is possible to reliably prevent a busy unit end from entering a loop state in which a start request becomes a busy response between a low-speed channel and a port and becomes a busy response even if the start request is made again to the unit end. In addition, it is possible to avoid a situation in which a check condition occurs due to a time-out due to a response delay to an input / output request of the host computer, thereby guaranteeing system performance.

<Table of Contents>
1. 1. System configuration Learning process 3. Busy response-busy end circulation check processing Time series processing Retry interrupt processing 1
6. Retry interrupt processing 2
7. Intelligent input / output ports

1. System Configuration FIG. 3 shows a system configuration of an input / output control device of the present invention using a magnetic tape device as a drive unit.

3, eight magnetic tape drive units 12-1 to 12-8 are connected to a magnetic tape control unit 10 functioning as an input / output control device via a device interface 22 in this embodiment. Connected. Drive unit numbers # 1 to # 8 are set in advance in the magnetic tape drive units 12-1 to 12-8.

The magnetic tape control unit 10 has eight input / output ports 20-1 to 20-8 in this embodiment. Port numbers A to H are defined for the input / output ports 20-1 to 20-8. In the following description, the ports are simply referred to as ports A to H.

Channel devices 16-1 to 16-8 provided in host computers 14-1 to 14-8 are connected to ports A to H of magnetic tape control unit 10 via channel buses 18-1 to 18-8. Is done. Here, channel numbers A to H are defined for the channel devices 16-1 to 16-8. In the following description, it is simply expressed as channel A to channel H.

The channel buses 18-1 to 18-8 between the channels A to H of the host computers 14-1 to 14-8 and the ports A to H of the magnetic tape control unit 10 have their own transfer speeds. For example, the channel bus 18-1 connecting the channel A and the port A is an electric channel bus, and its transfer speed is 4.5 MBs.

(4) As such an electrical channel bus 18-1, an IBM block multiplex channel interface (BMC) can be used. The channel bus 18-2 connecting the channel B and the port B is, for example, an optical channel bus, and its transfer speed is as high as 9 MBs. As such an optical channel bus 18-2, for example, an ESCON channel manufactured by IBM can be used.

(4) Channel buses having their own transfer rates are used for the remaining channel buses 18-3 to 18-8. Of course, the present invention is intended for a case where the transfer speed of at least a plurality of channel buses is two types, high speed and low speed. For example, the electrical channel bus 18-1 having a transfer speed of 4.5 MBs is a low-speed channel bus, whereas the channel bus 18-2 using an optical channel bus is a high-speed channel bus because the transfer speed is 9 MBs. Become.

In the following description, the channel A of the low-speed channel bus 18-1 is called a low-speed channel, and the channel B of the high-speed channel bus 18-2 is called a high-speed channel. Similarly, for ports A and B, port A is a low-speed input / output port and port B is a high-speed input / output port.

FIG. 4 shows a hardware configuration of the magnetic tape control unit 10 of FIG. The magnetic tape control unit 10 includes a host interface unit 24, a buffer memory 26, a formatter unit 28, and a communication information memory table 30. The host interface unit 24 includes an MPU 32, firmware 34, and an interface processor 36.

The interface processor 36 is provided with ports A to H realized by input / output ports 20-1 to 20-8 connecting a channel bus to a host computer. The formatter unit 28 includes an MPU 38, firmware 40, and a formatter processor 42.

The input / output control of the present invention can be realized by the control functions of the MPU 32, the firmware 34, and the interface processor 36 provided in the host interface unit 24. The buffer memory 26 temporarily stores data exchanged between the host computer and the magnetic tape drive unit. By the data transfer via the buffer memory 26, the transfer between the input / output control device 10 and the channel side and the transfer between the input / output control device 10 and the magnetic tape drive unit side are performed asynchronously.

When the MPU 32 provided in the host interface unit 24 receives a start request from any of the ports A to H in the interface processor 36, the MPU 32 accepts the start request on condition that no other port is being connected, and connects to the channel bus. Then, transfer processing of a channel command word based on an input / output request from the host computer is performed.

The channel command is usually a continuous command chain of different command words for realizing a series of command sequences, and a data chain for repeatedly transferring a read command or a write command when transferring data in block units. There is ning.

(4) Each time one transfer process is performed by such a channel command, the channel device issues a start I / O request (start I / O command) to the corresponding port of the magnetic tape control unit 10 to make a start request. At the time of this activation request, usually, one of drive unit numbers # 1 to # 8 of the magnetic tape drive unit is designated. The interface processor 36 monitors the start I / O request from the channel bus for the ports A to H. When recognizing the start I / O request, the interface processor 36 starts the start I / O on the condition that no other port is being connected. A connection completion response indicating a normal end to the O command is returned. If another port is being connected when the start I / O request is received, a busy response is basically returned.

The MPU 32 decodes the command from the channel side received via the interface processor 36 and writes various information such as parameters necessary for controlling the magnetic tape drive unit into the communication information memory table 30. The data transferred for writing to the magnetic tape drive unit is written to the buffer memory 26.

The MPU 38 of the formatter unit 28 cyclically refers to the communication information memory table 30 asynchronously with the MPU 32. When recognizing information necessary for control of the magnetic tape drive unit or data transfer, the MPU 38 via the format processor 42 , And instructs processing operations for various controls and data transfer to the magnetic tape drive unit having the designated drive unit number.

The MPU 38 cyclically detects the states of the magnetic tape drive units 12-1 to 12-8 and writes the detection result in the communication information memory table 30. Therefore, when the host interface unit 24 receives a sense command for confirming the state of the magnetic tape drive unit from the channel side, the MPU 32 recognizes the state of the magnetic tape drive unit by referring to the communication information memory table 30, and Can respond to commands.

Further, the interface processor 36 writes the data transferred from the channel bus into the buffer memory 26 after compressing the data, and decompresses the compressed read data read from the magnetic tape drive unit into the buffer memory 26 into the original data and sends it to the channel bus. A function as a compression / decompression unit for sending out is provided. In this data compression / expansion processing, it is possible to specify whether to expand or compress the data or to process the data as it is by using a bit flag of a set command sent at the beginning of the read or write request.

On the other hand, as an option, a CRT 35 and a keyboard 45 are provided via the device interface 25. This allows the operator to externally set various parameters necessary for input / output control of the MPU 32 of the host interface unit 24. Of course, the control parameters of the MPU 32 may be set using a CRT and a keyboard on the host computer side.

2. Learning Process FIG. 5 shows an embodiment of the present invention, in which the magnetic tape control unit 10 is provided with two ports A and B.

(4) The magnetic tape control unit 10 is provided with a route control unit 46, and has a function as a channel switch for selecting one of the ports based on a start request from the channel bus to the port A or the port B. Ports A and B are provided with timers 52 and 58, respectively. The timers 52 and 58 start at a busy end to the channel bus from the ports A and B, and then stop when receiving a start request from the channel bus.

More precisely, the start-up time measured by the timers 52 and 58 is from the time when the busy end is responded with the completion of the connection of the other port after the busy response is made to the channel bus, and the busy release receiving the busy end is started. This is the time until an activation request from the waiting channel device is received by the port. Therefore, the start-up time itself represents the time when the channel device receives the unit end and issues the start-up request again in the busy release waiting state, and depends on the transfer speed of the channel bus.

Here, the port A is a low-speed port connected to the low-speed channel bus 18-1, and the port B is a high-speed port connected to the high-speed channel bus 18-2. Therefore, the activation time T1 of the low-speed port A measured by the timer 52 is longer than the activation time T2 of the high-speed port B measured by the timer 58. The activation time measurement storage unit 48 stores the activation time T1 of the low-speed port A and the activation time T2 of the high-speed port B by the timers 52 and 58.

The magnetic tape control unit 10 further includes a busy ratio measurement storage unit 50. The busy ratio measurement storage unit 50 uses the count values of the start number counter 54 and the busy number counter 56 provided for the port A, and the start number counter 60 and the busy number counter 62 provided for the port B, and calculates the values of the ports A, The busy ratios R1 and R2 are calculated and stored for each B.

Taking port A as an example, the number-of-activations counter 54 is counted up every time there is an activation request for the port A from the channel bus 18-1, and represents the total number of active activation requests for the port A. The busy number counter 56 counts the number of times that the other port B has made a busy response during the connection among the activation requests to the port A.

The busy ratio measurement storage unit 50 divides the value of the busy number counter 56 by the value of the number-of-starts counter 54 each time the number-of-starts counter 54 counts up, that is, every time there is a start request, The busy ratio R1 is calculated. This point is the same for the start number counter 60 and the busy number counter 62 of the port B. Every time the start request is received, the value of the busy number counter 62 is divided by the value of the start number counter 60, and the busy rate of the port B is calculated. Calculate and store R2.

Furthermore, in the start-up time measurement storage unit 48, the start-up times T1 and T2 of the ports A and B measured by the timers 52 and 58 are not stored as they are, but the start-up time differs depending on the situation at that time. , Maximum time Tmax, minimum time Tmin and average time Tav. The maximum time Tmax is stored by comparing the maximum time Tmax obtained up to the previous time with the activation time T obtained this time. If the activation time T is large, the maximum time Tmax up to that time is updated. The maximum time Tmax is left. The minimum time Tmin is similarly updated.

The average time Tav can be obtained by dividing the sum of the activation times up to the present time by the number of activation requests. If the sum of all the start-up times is taken, the data bit length becomes too large, so it is desirable to calculate a moving average for each fixed number of start-up times.

Upon receiving the activation request from the high-speed port B, the route control unit 46 does not immediately perform the connection completion response even if the port A is in the non-connection state, and refers to the busy rate measurement storage unit 50 to Are compared, and the route control is performed so that the busy rates R1 and R2 become the same. Normally, since the busy rate R1 of the low-speed port A is large and the busy rate R2 of the high-speed port B is small, the activation time T1 of the low-speed port A having the large busy rate is read from the activation time measurement storage unit 48, and the read low-speed port is read. The port B sets a waiting time for a start request to the low-speed port A over the start time T1 of A.

When there is an activation request to the low-speed port A during the waiting time T1 of the activation request to the port A, the route control unit 46 couples the port A to the channel bus 18-1 to perform a transfer process, and first executes the activation request. With respect to the high-speed port B having the error, a busy response is returned. As a result, the low-speed port A having a high busy rate can preferentially receive the activation request, and the busy rate with the high-speed port B can be made substantially equal.

Further, since the maximum time Tmax, the average time Tav, and the minimum time Tmin are stored in the activation time measurement storage unit 48 as the activation time T1 of the low-speed port A, the relationship between the busy rates R1 and R2 of the ports A and B is determined. For example, the waiting time of the activation request to the low-speed port A is set as follows.

1) If R1> R2, set the maximum time Tmax as the waiting time.

2) If R1 = R2, set the average time Tav as the waiting time.

3) If R1 <R2, set the minimum time Tmin as the waiting time.

FIG. 6 is a time chart of the startup time measuring process in the magnetic tape control unit 10 of FIG. Now, when the host computer 14-2 issues a start I / O request 100 to the port B, since the port A is not used at this time, a coupling completion response 102 indicating a normal end is returned, and the channel B and the port B Perform transfer processing 104 and 106.

If a start I / O request 108 is made from the low-speed channel A during the transfer processes 104 and 106, a busy response 110 is returned from the low-speed port A. When the transfer processing is completed, the unit end 112 is reported from the high-speed port B to the high-speed channel B, and then the busy end 114 is issued from the low-speed port A to the low-speed channel A waiting for the busy release. In response to the busy end 114, the low-speed channel A recognizes the release of the busy state and issues a start I / O 116.

(5) The timer 58 in FIG. 5 measures the time T1 until the start I / O request 116 is received from the busy end 114 at the low-speed port A as the activation time. The low-speed port A that has received the start I / O request 116 issues a connection completion response 118 indicating normal termination, and performs transfer processing 120 and 122 on the low-speed channel A and the low-speed port A.

(4) If a start I / O request 124 is made from the high-speed channel B during the transfer processes 120 and 122, a busy response 126 is returned from the high-speed port B. When the transfer process is completed, the low-speed port A reports the unit end 128 to the low-speed channel A, and then the high-speed port B issues the busy end 130 to the high-speed channel B waiting for the busy release. In response to the busy end 130, the high-speed channel B recognizes the release of the busy state and issues a start I / O 132.

(5) The timer 60 in FIG. 5 measures the time T2 until the start I / O request 132 is received from the busy end 130 at the high-speed port B as the activation time. FIG. 7 shows input / output control by the route control unit 46 using the storage time of the activation time measurement storage unit 48. Now, if a start I / O request 142 from the high-speed channel B is made to the high-speed port B and a transfer I / O request 148 from the low-speed channel A is performed while the transfer processing 145 and 146 are being performed by the coupling completion response 114, This results in a busy response 150.

When the low-speed channel A is in a state of waiting for the busy release, the transfer processing 145, 146 is completed and the unit end 146 is output. When the busy end 156 is output from the low-speed port A, the waiting time T based on the activation time T1 is set. Make the settings for During the waiting time T0, a start I / O request 156 from the high-speed channel B to the high-speed port B is made first. However, since it is within the waiting time T0, the start I / O request 156 is not accepted and is waited.

(4) Subsequently, the low-speed channel A issues a start I / O request 158 after a time T1 'from receiving the busy end 154. At this time, the magnetic tape control unit 10 is in the waiting time T for giving priority to the activation request to the low-speed port A in the setting of the waiting time T, accepts the start I / O request 158, returns the coupling completion response 160, and Enter 162 and 164.

Then, a high-speed port B returns a busy response 166 to the high-speed channel A in response to the start I / O request 156. When the transfer processes 162 and 164 are completed, the unit end 168 is issued and the busy end 170 is issued. Then, transfer processes 174 and 176 are performed by coupling the high-speed channel B and the high-speed port B.

As described above, when the start request to the high-speed port B is accepted, the waiting time T over the start time of the low-speed port A is provided, and the processing is performed after waiting for the start request to the low-speed port A. Even if there is a continuous request, if there is an activation request for the low-speed port A, it can be normally received and processed, and it is possible to prevent the service from being concentrated on the high-speed port B side.

FIG. 8 is a flowchart of an input / output control process using the start-up time and the busy rate in the magnetic tape control unit 10 of FIG.

(4) If there is a start request in step S1, the process proceeds to step S2 to check whether the port is a high-speed port. If the port is a high-speed port, the process proceeds to step S3. For example, the startup time T1 measured at the low-speed port is set in the timer as the waiting time T, and a startup request for the low-speed port is checked in step S5 until the startup time T1 times out in step S4. I do.

(4) If it is determined in step S5 that a low-speed port has been activated during the activation time T1, the process proceeds to step S6, in which the low-speed port is connected to the low-speed channel and transfer processing is started. At the same time, a busy response is made from the high-speed port to the high-speed channel in step S7. When it is determined in step S8 that the transfer process on the low-speed side has been completed, the unit end is output from the low-speed port in step S9, and then the busy end is output from the high-speed port. For this reason, a start request is made again from the high-speed port waiting for the busy release, and the processing in step S1 is performed again.

On the other hand, if the activation request from the low-speed port is determined in step S2, the process proceeds to step S10, and the transfer control is performed by connecting the low-speed port to the channel on condition that the high-speed port is not being connected. If the high-speed port is being connected, the control unit end is responded from the low-speed port, and the normal processing is performed in which the low-speed port issues an activation request again after waiting for the response of the control unit end due to the end of the high-speed port connection.

9 is a processing operation of the startup time measurement storage unit 48 of FIG. 5, and the processing operation is performed independently for each of the ports A and B. For example, taking port A as an example, a busy end response is determined in step S1, and the process proceeds to step S2 to start a timer. Subsequently, in step S3, reception of a start request to port A is checked. When the start request is received, the process proceeds to step S4, and the timer started in step S2 is stopped.

Subsequently, in step S5, the time held in the timer is fetched and stored as the activation time. Next, in step S6, the average time Tav including the startup time measured this time is calculated. In step S7, if the condition of the minimum time is satisfied, the current minimum time Tmin is updated. If the condition is satisfied, the maximum time Tmax is updated.

フ ロ ー チ ャ ー ト The flowchart of FIG. 10 shows the details of setting the low-speed port startup time T1 in the timer in step S3 of FIG. First, in step S1, the busy rate R2 of the high-speed port B receiving the activation request and the busy rate R1 of the low-speed port A waiting for the request are calculated. Each of the busy ratios R1 and R2 is a busy ratio measurement storage obtained by dividing the count values of the busy number counters 56 and 62 provided in the ports A and B of FIG. This is the value stored in the unit 50. Subsequently, in step S2, the magnitude relationship between the busy rate R1 of the low-speed port A and the busy rate R2 of the high-speed port B is compared. If the busy rate R1 of the low-speed port is larger than the busy rate R2 of the high-speed port, the process proceeds to step S3, where the maximum time Tmax of the startup time of the low-speed port A stored in the startup time measurement storage unit 48 is set as the waiting time. I do. If the busy rate R1 of the low-speed port is equal to the busy rate R2 of the high-speed port, the average time Tav of the activation time of the low-speed port is set to the waiting time in step S4. Further, when the busy rate R1 of the low-speed port is smaller than the busy rate R2 of the high-speed port, the process proceeds to step S5, and the minimum time Tmin of the activation time of the low-speed port is set as the waiting time.

Note that the waiting time is not limited to the setting of the startup time based on the busy rate of the high-speed port and the low-speed port shown in FIG. 10, but the waiting time is determined so that the busy rate of the high-speed port and the busy rate of the low-speed port become substantially equal. An appropriate method can be adopted. For example, only the average time Tav is used as the activation time of the low-speed port, and the time obtained by multiplying the average time by a predetermined weighting factor instead of the maximum time or the minimum time in steps S3 and S5 is determined and set. Good.

FIG. 11 shows a modified embodiment of the present invention. In this embodiment, at the time of unit end of a high-speed port, a start-up time from a response of a busy end from a low-speed port to a low-speed channel to the reception of a start-up request is measured. The request is made to wait for the measured start-up time, and a processing request is received from a low-speed channel for a low-speed port during that time.

In FIG. 11, a startup time measuring unit 230 is provided for the low-speed port A. The start-up time measuring unit 230 measures the start-up time T from when the low-speed port A issues a busy end to the low-speed channel A until it receives a start I / O request (start-up request), as in the time chart of FIG. The waiting time determining unit 232 sets a waiting time T0 in the route control unit 46 based on the measured time T of the activation time measuring unit 230. The setting of the waiting time T0 may be the same as the measurement time T.

The waiting time T0 may be variably set according to the measurement time T. Normally, if the actual waiting time T0 is made longer than the measuring time T, the service allocation to the low-speed side can be made effective. For example, the waiting time T0 obtained by multiplying the measuring time T by a predetermined coefficient K of 1 or more is used. Is set variably.

(4) The waiting time T0 may be set by an operator's input operation. Therefore, a display unit 234 and an input unit 236 are provided outside the waiting time determination unit 232. The functions of the display unit 234 and the input unit 236 are realized by the device interface 25, the CRT 35, and the keyboard 45 in FIG.

The operator reads out and displays the current waiting time T0 set in the waiting time determination unit 323 by operating the input unit 236 on the display unit 234, and considers the busy state of each channel and the operation mode of the host computer at that time. An arbitrary waiting time T0 is input and set in the waiting time determination unit 232.

When the route control unit 46 responds with a unit end at the end of the transfer of the high-speed port B, it issues a busy response even if there is a start request to the high-speed port B for the waiting time T0 given by the waiting time setting unit 232, and waits. . If there is an activation request to the low-speed port A during this waiting time T0, it is immediately accepted and the transfer process is performed.

When the waiting time T0 has timed out or the unit ends at the end of transfer of the low-speed port A, a busy end is issued from the high-speed port B, and a high-speed channel is again requested to start and accepted.

3. Busy Response-Busy End Circulation Check Process FIG. 12 shows another embodiment of the present invention. In this embodiment, a continuous response to a start request from a high-speed port causes the low-speed port to repeat a busy response to a start request based on a busy end (busy release response). A service is preferentially assigned to a port.

(4) Each of the low-speed port A and the high-speed port B of the magnetic tape control unit 10 is provided with a counter 64, 66. The counters 64 and 66 are incremented by one when a busy end response and a busy response to an activation request based on the responded busy end are performed. In other words, one circulation of busy response-busy end is detected and counted up.

The circulation number determination unit 68 determines whether or not the count value of the counters 64 and 66, that is, the number of circulation times of the busy response-busy end has reached a predetermined value. When the circulation number determination unit 68 determines that the count value of the counter 64 or the counter 66 has reached the predetermined value, the route control unit 46 receives this determination output and the port A or the port A whose circulation number exceeds the predetermined number. Control is performed such that a start request is preferentially received for port B.

フ ロ ー チ ャ ー ト The flowchart of FIG. 13 shows the processing operation of FIG. First, in step S1, it is checked whether there is a start request for port A or port B. When there is an activation request, the transfer processing is performed by connecting to the channel on condition that it is not being connected to another port. When the transfer process is completed in step S3, a unit end is returned in step S4.

At this time, if there is a port that has been busy responding, a busy end is responded from that port. For this reason, if the start request is made and the busy response is completed during the transfer due to the connection in step S2 at the other port, the corresponding counter shown in FIG. 12 at the busy end in step S4 changes the busy response-busy end circulation. The number is counted up by one.

Next, in step S5, it is checked whether or not there is a port whose busy response-busy end circulation number exceeds a certain value. If there is a port exceeding a certain value, the process proceeds to step S6, and priority processing of the activation request is assigned to the port exceeding the certain value. When the activation request is determined in step S7, it is checked in step S8 whether the port is a priority allocation port. If the port is not a priority allocation port, a busy response is returned in step S12.

As a result, only the activation request for the priority assignment port is accepted, and the transfer process is performed by coupling with the channel bus in step S9. When the transfer processing of the priority assignment port is completed in step S10, the circulation number counter provided in the priority assignment port is reset in step S11, and a unit end is returned. At this time, if there is another port that is in a waiting state due to a busy response in step S12, a busy end is issued from that port to make an activation request.

4. FIG. 14 shows another embodiment of the present invention. This embodiment is characterized in that the busy response time of another port during the connection of a certain port is stored, and the service is preferentially assigned to the port with the oldest busy response time at the end of the connection. .

The magnetic tape control unit 10 includes a busy response time storage unit 70 and a processing port determination unit 72 in addition to the ports A and B and the route control unit 46. The busy response time storage unit 70 stores a time at which a start response was issued to another port during connection of the port A or the port B and a busy response was performed. In this embodiment, since there are two ports, port A and port B, the response time of port B is stored during the connection of port A, and the response time of port A is stored during the connection of port B.

The processing port determination unit 72 refers to the busy response time storage unit 70 when the transfer process of the port being combined is completed and responds to the unit end, and determines the oldest time among the stored busy response times. Then, the start request is preferentially determined as the processing port, and is notified to the route control unit 46. The route control unit 46 preferentially processes the activation request from the port determined by the processing port determination unit 72.

In this embodiment, since there are only two ports A and B, if the port B makes a busy response during the connection of the port A, the processing port determination unit 72 determines the port B as the next port to receive priority. The route control unit 46 makes a busy response to the activation request from the port A, and accepts only the activation request from the port B. As a result, even if the port A is a low-speed port and the port B is a high-speed port, the route control unit 46 can alternately receive a start request for each successive start request, and the low-speed port A and the high-speed port B Can be made substantially uniform.

Actually, as in the embodiment of FIG. 3, the magnetic tape control unit 10 is provided with eight ports A to H. In this case, any one of the remaining seven ports is connected during the connection of a certain port. If there is an activation request, the busy response time at that time is stored. When the current transfer processing is completed and the unit ends, the start request is accepted by allocating the busy end from the port having the oldest time among the plurality of busy response times. .

フ ロ ー チ ャ ー ト The flowchart of FIG. 15 shows the processing operation of FIG. In step S1, a start request for a plurality of ports is monitored. If there is a start request for a specific port, in step S2, the port is connected to a channel bus to perform a transfer process. In step S3, the end of the transfer process is checked. When the transfer is completed, in step S4, a unit end is returned from the port being connected.

In steps S1 to S4, if there is an activation request from another port during connection of a certain port, the response time is stored in the busy response time storage unit 70. Therefore, in step S5 after responding with the unit end, the port with the oldest time among the busy response times is determined as the processing port, and in step S6, the busy end is output from the determined port. The busy release waiting channel receiving this busy end issues the activation request again.

(5) Subsequently, the activation request is checked in step S7. If there is an activation request, it is checked in step S8 whether or not the port is a priority allocation port. If the port is not the priority allocation port, a busy response is returned in step S12. As a result, only the activation request for the priority assignment port is accepted, and in step S9, the transfer processing is performed by coupling to the channel bus.

If the end of the transfer process is determined in step S10, the busy response time of the processing port is reset in step S11, the unit end is returned, and the process returns to step S13. If the busy response time remains, the process returns to step S13. Returning to S5, the process of determining the port having the oldest response time among the remaining busy response times as the processing port and issuing the busy end is repeated. If no busy response time remains, the process returns to step S1.

5. Retry interrupt processing 1
FIG. 16 shows another embodiment of the present invention. Embodiments of the present invention provide a method for responding to a status requesting a retry of a channel operation instead of responding to a busy state when a request for activation is received from another port while one port is associated with a channel. Upon completion of the transfer process, a retry start interrupt request is issued to the channel that has responded to the retry request with the status, and reconnection is performed.

The magnetic tape control unit 10 is provided with a retry interruption processing unit 74 in addition to the port A, the port B, and the route control unit 46. The retry interrupt processing unit 74 normally returns a busy response when, for example, a start request comes to the port B during the connection of the port A. In the fourth invention, the retry interrupt processing unit 74 requests the retry of the channel operation. The port B is temporarily disconnected from the channel bus.

Next, when the transfer processing by the connection of the port A is completed and the unit end is responded, an interrupt request for starting retry is made to the channel B which has responded with the status of the retry request, and reconnection is performed. The channel device that has received the response of the retry request status in response to the activation request by the retry interrupt processing unit 74 enters a wait state of the retry start of the channel operation, and thereafter receives the interrupt response of the retry start, Again, the command sequence from the activation request is started and recombined.

(5) By the processing of the retry interruption processing unit 74, the magnetic tape control unit 10 can determine which port to reconnect with, and provide an average service to each port. For example, if the activation request for the high-speed port B is continuous and if the activation request is issued to the low-speed port A during the connection of the high-speed port B, the retry interrupt processing unit 74 responds with the retry request status and Side waits for retry.

When the transfer processing of the high-speed port B is completed and the unit end is responded, the retry interrupt processing unit 74 issues an interrupt request for starting retry to the corresponding channel device via the low-speed port A and reconnects, and An activation request is reissued from the channel device that has received the retry start interrupt, and transfer processing is performed according to a series of command sequences.

As a result, even if the activation request continues on the high-speed port B side, the activation request for the low-speed port A generated during the connection of the high-speed port B is not excluded as a busy response, and the activation request for the low-speed port A is forcibly interrupted. Is accepted, and the low-speed port A and the high-speed port B can be provided on average.

FIG. 17 shows processing when a low-speed port A is requested to be activated during the connection of the high-speed port B in FIG. First, when a start I / O request 200 is sent to the high-speed port B from the high-speed channel B, a transfer completion 204 is performed after a connection completion response 202 is sent. If there is a start I / O request 208 from the low-speed channel A to the low-speed port A during this transfer, a retry interrupt status response 210 is performed, and the low-speed channel A waits for retry activation.

When the transfer processing 204, 206 is completed and the control unit end 212 is output, a retry start interrupt notification 214 is sent from the low speed port A to the low speed channel A, and the low speed channel in the retry start wait state is sent. The start I / O request 216 is issued again from A. In response to this, a reconnection causes a connection completion response 218 to be issued, and transfer processes 220 and 222 are performed in connection between the low-speed channel A and the low-speed port A. When the transfer process is completed, the control unit end 224 is output.

フ ロ ー チ ャ ー ト The flowchart in FIG. 18 shows the processing operation of the embodiment in FIG. First, in step S1, the presence or absence of a start request is checked. If there is a start request in a specific port, the process proceeds to step S2, and the transfer process is performed by connecting to a channel on condition that other ports are not in a connected state. I do. During the transfer, until it is determined in step S3 that the transfer is completed, it is checked in step S4 whether another port has a start request.

If there is an activation request, the process proceeds to step S5, and it is checked whether or not a retry status is to be responded to the channel device which has issued the activation request in step S5. Here, if the port currently being combined is a low-speed port and the port that received the activation request during the combination is a high-speed port, there is no need to process it preferentially. return.

On the other hand, if the port currently being combined is a high-speed port and the port that has received the activation request during the combination is a low-speed port, processing must be given priority, so the process proceeds to step S6 and retry. Respond the status.

(4) When it is determined in step S7 that the transfer has been completed, the process proceeds to step S8, where a unit end is returned from the port being connected. Subsequently, in step S9, it is checked whether or not a response to the retry status has been made during the transfer. If so, in step S10, an interrupt request to start the retry is issued from another port that has made the response to the retry status. Issue

If the retry status has not been returned during the transfer, a unit end is returned from another port that has made the busy response in step S11, and the process returns to step S1 again.

In the above embodiment, two ports, a low-speed port A and a high-speed port B, are taken as an example. However, as shown in FIG. 4, the same can be applied to eight ports A to H. When the number of ports becomes three or more, interrupt requests may be received by a plurality of other ports during the connection of a certain port. Therefore, the retry interrupt processing for the interrupt request is prioritized, and the priority is set according to the priority. What is necessary is just to notify the interruption of the retry start.

6. Retry interrupt processing 2
FIG. 19 shows another embodiment of the present invention. According to the present invention, when a predetermined interrupt condition is satisfied during the connection of a certain port, the connection is temporarily disconnected by responding the status of the retry request from the currently connected port to the channel. Next, the status of the busy response, such as the latest busy response time and the number of busy times, is checked for all the ports, or the interrupt request is analyzed to determine which port has higher priority for the service. Then, the port that has determined the priority processing responds with the unit end, and performs the transfer processing preferentially. When the transfer processing is completed, a retry start interrupt request is issued from the port from which the connection has been disconnected, the connection is re-connected, and the processing once interrupted is resumed.

実 施 The embodiment of FIG. 19 is characterized in that an interrupt is generated at fixed time intervals as an interrupt condition. The magnetic tape control unit 10 is provided with an interrupt timer 80, a busy response storage unit 82, and a retry interrupt processing unit 76 in addition to the port A, the port B, and the route control unit 46. The interrupt timer 80 generates a timer output to the retry interrupt processing unit 76 at predetermined time intervals, and causes the retry interrupt processing unit 76 to perform an interrupt process.

The busy response storage unit 82 stores, for example, the time of the latest busy response and the number of busy times as information indicating the busy state of the port A and the port B. The retry interrupt processing unit 76 starts an interrupt operation when the interrupt timer 80 times out, for example, during the connection of the high-speed port B, and responds to the channel device from the high-speed port B that is currently being connected with the status of the retry request. , Once disconnect.

After disconnecting the connection with the high-speed port B, all the ports stored in the busy response storage unit 82, that is, the busy state of each of the ports A and B, for example, the latest time and the number of busy times of the busy response are referred to. Determine if service for the port should be prioritized. For example, since the high-speed port B is currently being processed, the busy time for the low-speed port A, which is another port, is the oldest time and the busy count indicates a certain value. 76 determines the low-speed port A as a priority processing port.

(4) When the processing port is determined, the retry interruption processing unit 76 causes the determined processing port A to respond the unit end to the channel device through the route control unit 46. Upon receiving the unit end from the port A, an activation request is made to the low-speed port A from the channel device in the waiting state by the busy response up to that time, and the transfer is performed after being effectively coupled.

When the transfer processing on the low-speed port A side is completed and the unit end is responded, the retry interrupt processing unit 76 interrupts the processing and issues a retry start interrupt request to the channel device from the high-speed port B that has been disconnected. Issue. In response to the interrupt request, the channel device issues an activation request to the high-speed port B, and the interrupted transfer process is resumed. When the priority processing of the low-speed port A is completed and the unit end is issued, the busy response time and the busy count for the low-speed port A in the busy response storage unit 82 are reset at the same time.

タ イ ム The time chart of FIG. 20 shows the operation of the retry processing of FIG. First, a start I / O request 300 is made from the high-speed channel B to the high-speed port B, and since no other low-speed port A is being connected, a connection completion response 302 as a normal end is returned. The high-speed port B performs transfer processing 304 and 306. When a timer interrupt 308 is generated by the interrupt timer during this transfer processing, a retry status response 310 is issued from the high-speed port B to the high-speed channel B to disconnect the connection.

(4) After the connection is disconnected, the status of the busy response is checked for all ports A and B. If there is a busy response to the low-speed port A at this time, the low-speed port A is determined as a port to be processed with priority. Then, the unit A 314 is issued from the port A for which priority processing is determined to the low-speed channel A, and the start I / O request 316 is issued from the low-speed channel A.

(4) The start I / O request 316 is normally accepted by the low-speed port A, and after returning the coupling completion response 318, the transfer processing 320, 322 is performed between the low-speed channel A and the low-speed port A. When this transfer processing is completed, the unit end 324 is responded from the low-speed port A, and then a notification 326 of a retry start interrupt is sent to the high-speed channel B from the high-speed port B once disconnected.

For this reason, a start I / O request 328 is issued from the high-speed channel B that has been in the retry waiting state, is accepted by the high-speed port B, ends normally, returns a coupling completion response 330, and transfers the temporarily interrupted transfer processing. Processing is restarted as processing 332, 334. When the restarted transfer processing is completed, the unit end 336 is issued from the high-speed port B.

As described above, when the interrupt condition is satisfied, the magnetic tape control unit disconnects the current connection, determines the port to be processed preferentially according to the busy state, and performs the transfer processing in an interrupt manner, thereby enabling the high-speed port. , It is possible to prevent the busy unit end from circulating on the low-speed port side.

フ ロ ー チ ャ ー ト The flowchart in FIG. 21 shows the processing operation of the retry interrupt process using the interrupt timer in FIG. First, in step S1, it is checked whether or not there is a start request for each port. If there is a start request for a certain port, the process proceeds to step S2, and the connection with the channel is made on condition that there is no connection with other ports. Start the transfer process.

During the transfer, the time-out of the interrupt timer is monitored in step S4 until the transfer end is determined in step S3. When the time of the interrupt timer expires during the transfer, the process proceeds to step S5, where a status response of the retry request is made from the port currently being connected, and the connection is disconnected. Next, at step S6, the priority response port is determined by analyzing the factors of the busy response of all ports, for example, the time and the number of times.

In step S7, it is checked whether the determined priority processing port is the same as the disconnection port separated in step S5. If they are not the same port, in step S8, a unit end is returned from the determined port to the channel, and an activation request accompanying this is received in step S9, the ports are connected, and the transfer processing is performed.

Subsequently, in step S10, when the transfer process by the interrupt is completed, in step S11, the connection is cut off by responding to the unit end, and then in step S12, the connection is cut off to the channel device which is in the waiting state for retry start by disconnection. A retry start interrupt request is issued from the disconnection port.

(4) In response to this interrupt request, a start request is made again by the channel device in the retry start waiting state. This is determined in step S1, and the port and channel are connected again in step S2 to restart the transfer process. When the end of the restarted transfer processing is determined in step S3, a unit end is returned in step S13, and a series of transfer processing ends.

On the other hand, if the highest priority processing port determined by analyzing the factors of the busy response of all ports in step S6 is the same port as the port from which the connection was disconnected in step S5, the process immediately proceeds to step S12. A retry start interrupt request is issued from the disconnection port, and the transfer processing by reconnection is immediately restarted.

As is clear from the flowchart of FIG. 21, when the interrupt condition by the interrupt timer is satisfied during the connection of the high-speed port B of FIG. 19, the priority processing of the low-speed port A in the busy waiting state is determined, and the low-speed port A is determined by the interrupt. The transfer process on the side is terminated, and then the interrupted transfer process of the high-speed port B is restarted.

Also, when the interrupt condition by the interrupt timer is satisfied during the processing on the low-speed port A side, if the number of busy responses is biased toward the low-speed port side, the low-speed port A, which is the same as the disconnected port as the highest priority processing port, is re-established. The priority processing port is determined, and in this case, the transfer processing at the low-speed port A interrupted by the interrupt request for starting retry for reconnection is immediately resumed. Of course, depending on the situation, there may be a case where the transfer processing on the high-speed port side is preferentially processed during the processing on the low-speed port.

In the embodiment shown in FIGS. 19 to 21, two ports A and B are used as an example. However, as shown in FIG. 5, the magnetic tape control unit 10 is actually provided with eight ports A to H. When receiving an interrupt notification from the interrupt timer, the retry interrupt processing unit 76 checks the busy response states of the eight ports A to H to determine the port for which priority processing is to be performed.

FIG. 22 shows another embodiment of the present invention. In this embodiment, it is determined that an interrupt condition has been satisfied by executing a predetermined number of command processes in each port, and a retry interrupt process is executed. It is characterized in that.

In FIG. 22, the magnetic tape control unit 10 includes a low-speed port A, a high-speed port B, a route control unit 46, a retry interruption processing unit 76, a busy response storage unit 82, and command counters 84 and 86. The command counter 84 counts the number of command executions of the low-speed port A. The command counter 86 counts the number of command executions of the high-speed port B.

The retry interrupt processing unit 76 executes a retry interrupt process when the count value of the command counter 84 or 86 reaches a predetermined number of times. For example, a series of command sequences is executed in the transfer processing by the connection of the high-speed port B, and the command counter 86 counts up as the command is executed. When the retry interrupt processing unit 76 determines that the count value at this time has exceeded a certain number, the port B that is currently being connected sends a status response of a retry request to the channel device to disconnect the connection.

(4) After disconnecting the connection, the retry interrupt processing unit 76 refers to the busy response storage unit 82 and checks the status of the previous busy response for all ports A and B. Specifically, the latest response time and the number of times of busy response of each of the ports A and B are checked. Then, a port having a long busy response time and a large number of busy responses is determined as a port for which the highest priority processing is performed. In this case, the low-speed port A is determined as the highest priority processing port.

In response to this determination, the route control unit 46 responds a busy end to the channel device from the low-speed port A, causes the low-speed port A to issue an activation request from the channel device that has received the busy end, and performs a transfer process by coupling the port A. . When the transfer process by the interrupt from the low-speed port A is completed, the retry interrupt processing unit 76 issues a retry start interrupt request from the high-speed port B following the unit end response from the low-speed port A, and connects the ports B. To resume the interrupted transfer process.

The details of the retry interrupt process are the same as those shown in FIG. 19 except that the command counters 84 and 86 count the number of command executions of the ports A and B, and start the retry interrupt process when the number of command executions reaches a certain value. 21 is the same as that of the first embodiment shown in FIG.

FIG. 23 shows another embodiment of the present invention. This embodiment is characterized in that retry interruption processing is performed when the busy ratio of each port reaches a certain value.

In FIG. 23, the magnetic tape control unit 10 is provided with a low-speed port A, a high-speed port B, a route control unit 46, a retry interruption processing unit 76, a busy response storage unit 82, and a busy ratio calculation unit 88. The busy rate calculation unit 88 can be realized by the start number counters 54 and 60, the busy number counters 56 and 62, and the busy rate measurement storage unit 50 shown in the embodiment of FIG.

The retry interrupt processing unit 76 determines whether the busy ratio R1 of the low-speed port A or the busy ratio R2 of the port B calculated by the busy ratio calculating unit 88 reaches a predetermined constant value. When the busy rate R1 or R2 reaches a certain value, a retry interrupt process is started. The retry interruption process is the same as in the first embodiment of FIG. 19 and the second embodiment of FIG.

{That is, the status of the retry request is returned from the port currently being connected, the connection is once disconnected, and the port to be processed with the highest priority is determined by referring to the busy response storage unit 82. A busy end is issued to the determined port, and a transfer process is performed upon receiving an activation request. When the transfer process due to the interrupt is completed, an interrupt request for starting retry is issued to the disconnected port to reconnect, and the interrupted transfer process is resumed.

In this embodiment, when the busy rate reaches a certain value and the retry interrupt processing is performed, the priority processing port is determined from the busy response status of all ports, that is, the busy response time and the busy count. However, the priority processing port may be determined by analyzing the busy rate itself that caused the interrupt. That is, the busy rates of all the ports may be analyzed, and the port having the highest busy rate may be determined as the priority processing port. This can be said to be the determination of the priority processing port by analyzing the interrupt factor itself.

In the embodiment shown in FIG. 19 and the embodiment shown in FIG. 22, similarly to the embodiment shown in FIG. 23, by providing the busy ratio calculating section 88, the busy ratio of all ports is analyzed at the time of retry interruption processing, and the busy ratio is analyzed. The port with the highest rate may be determined as the priority processing port.

7. FIG. 24 shows another embodiment of the present invention, in which a command analysis function is provided for each port so that commands executable during processing of other ports are analyzed and processing is performed in parallel. It is characterized in that.

In FIG. 24, the magnetic tape control unit 10 is provided with a command analysis execution unit 92 for the low-speed port A and a command analysis execution unit 94 for the port B. The command analysis execution units 92 and 94 supply control signals to the magnetic tape control unit 10 and the lower magnetic tape drive units 12-1 and 12-2 through independent control paths 98.

On the other hand, data transfer between the magnetic tape drive units 12-1 and 12-2 is performed by a data bus 96, and a data route control unit 90 for switching the port A and the port B to the data bus 96. Is provided. In the above-described embodiments of the invention, the command analysis execution unit and the data route control unit are provided in the magnetic tape control unit 10 as one route control unit.

The command analysis execution units 92 and 94 provided for each of the ports A and B analyze a command received in connection with the channel associated with the activation request, and determine whether the command can be executed even during data transfer at another port. Determine whether or not.

Commands that can be executed during data transfer by coupling other ports include motion systems such as a magnetic tape load operation, an unload operation, a fast forward operation, and a rewind operation on the magnetic tape drive units 12-1 and 12-2. And a sense command for notifying the operation state of the magnetic tape drive units 12-1 and 12-2. On the other hand, commands that cannot be executed during data transfer due to coupling of other ports include a read command and a write command.

When the command analysis execution units 92 and 94 receive a start request during data transfer due to connection of another port and analyze the reception of a motion or sense command, the command analysis execution units 92 and 94 issue a connection completion response and do not perform a busy response. , Execute motion or sense commands. In this case, the magnetic tape drive unit performing data transfer by coupling with another port and the magnetic tape drive unit of the motion or sense command executed in parallel must be different units. The unit is checked by the drive number received as a command parameter of the start I / O request.

The device bus between the magnetic tape control unit 10 and the magnetic tape drive units 12-1 and 12-2, which can independently process the data transfer system, the control system, and the sense system, includes a control bus 98 shown in FIG. In addition to the independent bus 96, a common bus configuration that can simultaneously perform command processing and data transfer can be used.

フ ロ ー チ ャ ー ト The flowchart of FIG. 25 shows the processing operation of FIG. First, in step S1, an activation request for a port is checked. When the activation request is received, in step S2, the port is connected to a channel and command transfer processing is performed. Next, in step S3, the received command is analyzed. By this command analysis, it can be determined whether the command is a motion command or a sense command without data transfer.

In the next step S4, it is determined whether the command is a command without data transfer, that is, a motion command or a sense command. If the command is a motion command or a sense command, the process proceeds to step S5 to check whether there is a magnetic tape drive unit in operation. If there is an operating magnetic tape drive unit, it is checked in step S6 whether the drive number obtained by analyzing the received command is the same as the currently operating drive number.

If they are the same, they cannot be executed regardless of the command, so a busy response is returned in step S10. If the drive unit numbers are different, a motion command or a sense command can be executed, so that a reception command is executed in step S7. Subsequently, when it is determined in step S8 that a series of transfer processes accompanying the command execution has been completed, a unit end response is returned in step S9, and the process returns to step S1 again. Of course, if there is a port that has made a busy response, a busy end is responded along with the unit end.

On the other hand, if it is a write command or a read command involving data transfer in step S4, the process proceeds to step S11, and it is checked whether data transfer is in progress on another port. If data transfer is in progress at another port, data transfer cannot be performed, so a busy response is returned in step S12, and the process returns to step S1.

If data transfer is not in progress at another port, a write command or a read command can be executed. Therefore, data transfer processing accompanying the command execution is performed in step S12. In response to the end, the process returns to step S1.

In each of the above-described embodiments of the present invention, an input / output subsystem constituted by a magnetic tape control unit and a magnetic tape drive unit using a magnetic tape as a storage medium is taken as an example. The present invention includes an input / output control device for an appropriate input / output device, such as a magneto-optical disk device and a magnetic disk device. The present invention is not limited by the numerical values shown in the embodiments.

Diagram for explaining the principle of the present invention Principle explanatory view of another embodiment of the present invention Configuration diagram of a system to which the present invention is applied Block diagram of the input / output control unit of the present invention Block diagram of an embodiment of the present invention Time chart of measurement of startup time in FIG. Time chart of input / output processing of FIG. Flow chart of the input / output processing of FIG. Flow chart of the startup time measurement of FIG. FIG. 5 is a flowchart of a waiting time timer set. Block diagram of a modified embodiment of the present invention Block diagram of another embodiment of the invention Flow chart of the input / output processing of FIG. Block diagram of another embodiment of the invention 14 is a flowchart of the input / output processing. Block diagram of another embodiment of the invention The time chart of the input / output processing of FIG. 16 is a flowchart of the input / output processing of FIG. Block diagram of a first embodiment of another invention Time chart of input / output processing of FIG. 19 is a flowchart of the input / output processing. Block diagram of another embodiment of the invention Block diagram of another embodiment of the invention Block diagram of another embodiment of the invention Time chart of input / output processing of FIG. 24 Block diagram of conventional device Time chart of busy unit end circulation occurring in conventional input / output control Illustration of conventional control for allocating time slots synchronized to clocks to input / output ports

Explanation of reference numerals

10: Magnetic tape control unit (input / output control device)
12-1 to 12-8: Magnetic tape drive unit (input / output device)
14-1 to 14-8: Host computer (upper device)
16-1 to 16-8: Channel devices 18-1 to 18-8: Channel buses 20-1 to 20-8: I / O ports (ports)
22: Device bus 24: Host interface unit 25: Device bus 26: Buffer memory 28: Formatter unit 30: Communication information memory tables 32, 38: MPU
34, 40: Firmware 35: CRT
36: interface processor 42: format processor 44: internal bus 45: keyboard 46: route control unit 48: activation time measurement storage unit 50: busy rate measurement storage unit 52, 58: timers 54, 60: activation number counters 56, 62: Busy number counters 64 and 66: Counter 68: Busy-unit end circulation number determining unit (determining unit)
74, 76: retry interrupt processing unit 80: interrupt timer 82: busy response storage unit 90: data route control unit 92, 94: command analysis execution unit 96: data bus 98: control bus

Claims (13)

A plurality of input / output ports connected to a plurality of channel devices on the host device side via channel buses having different transfer speeds,
At any one of the plurality of input / output ports, the number of loops in which a busy response to the activation request and a response to the release of the busy accompanying the transfer termination of the other input / output ports are repeated is counted, and the number of loops reaches a predetermined value. A determination unit for determining whether or not to exceed;
When an input / output port whose loop count exceeds a predetermined value is determined by the determination unit, a route control unit that preferentially processes a start request of the determined input / output port;
An input / output control device comprising:
2. The input / output control device according to claim 1, wherein the route control unit accepts only a start request for the determination port and makes a busy response to a start request for another input / output port. Output control device.
At one of a plurality of I / O ports connected to a plurality of channel devices on the host device side via channel buses with different transfer speeds, a busy response to a start request and a release of busy at the end of transfer of another I / O port A determination step of counting the number of loop states in which the response is repeated, and determining whether the number of loops exceeds a predetermined value;
When an input / output port whose loop count exceeds a predetermined value is determined in the determination step, a route control step of preferentially processing a start request of the determined input / output port;
An input / output control method characterized by comprising:
4. The input / output control method according to claim 3, wherein the route control step accepts only a start request for the determination port and makes a busy response to a start request for another input / output port. Output control method.
A plurality of input / output ports connected to a plurality of channel devices on the host device side via channel buses having different transfer speeds,
A busy response time storage unit for storing a time at which a busy response to an activation request is made for each of the plurality of input / output ports;
A processing port determining unit that determines, as a priority processing port, an input / output port having the oldest response time among the busy response times each time transfer processing for the activation request is completed;
A route control unit that preferentially processes the activation request of the priority processing port determined by the processing port determination unit;
An input / output control device comprising:
6. The input / output control device according to claim 5, wherein the route control unit accepts only a start request for the priority processing port and makes a busy response to a start request for another input / output port. Input / output control unit.
A busy response time storing step of storing a time at which a busy response to an activation request is made for each of a plurality of input / output ports connected to a plurality of channel devices on the host device side via channel buses having different transfer speeds;
A processing port determining step of determining an input / output port having the oldest response time among the busy response times as a priority processing port each time transfer control for the activation request is completed;
A route control step of preferentially processing the activation request of the priority processing port determined in the processing port determination step,
An input / output control method characterized by comprising:
8. The input / output control method according to claim 7, wherein the route control step accepts only a start request for the priority processing port and makes a busy response to a start request for another input / output port. I / O control method.
A plurality of input / output ports connected to a plurality of channel devices on the host device side via channel buses having different transfer speeds,
A route control unit that performs a connection with a start request from a channel device to any of the plurality of input / output ports, a transfer process during the connection, and a response of an end status accompanying the transfer end;
During the connection between the specific channel device and the input / output port by the route control unit, when a start request is issued from another channel device to another input / output port, a retry status is returned from the other input / output port. By disconnecting the connection with the other channel device, at the end of the connection between the currently processed I / O port and the channel device, the other I / O port notifies the other channel device of a retry start interrupt notification. A retry interrupt processing unit for retrying the start request;
An input / output control device comprising:
A plurality of input / output ports connected to a plurality of channel devices on the host device side via channel buses having different transfer speeds,
Coupling associated with an activation request from a channel device to one of the plurality of I / O ports, transfer processing during coupling, end status response upon completion of transfer, and activation while other I / O ports are coupled A route control unit for performing a busy response to the request,
When a predetermined interrupt condition is satisfied during the transfer processing by coupling the specific channel device and the input / output port by the route control unit, the transfer process is interrupted by responding a retry status from the input / output port to the channel device. The priority processing port is determined by analyzing the busy response status of all the ports, and the priority processing port responds to the other channel device with the end status to make a start request. A retry interrupt processing unit for notifying the channel device of the retry start interrupt from the input / output port and resuming the interrupted transfer process at the end of the accompanying transfer process;
An input / output control device comprising:
11. The input / output control device according to claim 10, wherein the retry interrupt processing unit performs a retry interrupt process each time a predetermined time is reached.
11. The input / output control device according to claim 10, wherein the retry interrupt processing unit performs a retry interrupt process when the number of command processes of the combined input / output port reaches a predetermined value. I / O control unit to do.
11. The input / output control device according to claim 10, wherein the retry interrupt processing unit reaches a predetermined value in a busy response to a start request to another input / output port during the connection of the input / output port. An input / output control device characterized by performing a retry interruption process.

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