JPH0612359A - Input/output control method and system therefor - Google Patents

Abstract

PURPOSE:To speed up the processing of an input/output request by decreasing the overhead accompanying command transfer between an input/output control ler and an external storage controller. CONSTITUTION:Input/output requests 130 to a disk device 132 which are issued by a host device are registered in input/output request queues 122 and 113 by an input/output processor 101 and channel programs 123-125 corresponding to one or, preferably, plural input/output requests registered in the input/output request queues are read together out of a main storage device 121 and sent out to a disk controller 131, which temporarily stores those channel programs by itself and also executes plural commands included in them while controlling their execution timing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer system, and more particularly to a data input / output control method and apparatus which are required to have high throughput and high speed response.

[0002]

2. Description of the Related Art Generally, an input / output control device is located between a host device such as a central processing unit and a device such as a secondary storage device typified by a magnetic disk device. Its main purpose is to output asynchronously. That is, in the prior art, the host device stores a set of channel command words (also called a channel program) indicating the contents of the input / output request in the main storage device, and further, the input / output request writes data to the device. When requesting, store the data in the main memory,
Thereafter, the address of the set of channel command words and the input / output request were sent to the input / output control device.

The input / output control device has registered this input / output request in an input / output request queue provided in the main storage device, and thereafter, extracts the input / output request from this queue as appropriate and transfers it to the device. This input / output control device allows the host device to
It is possible to continue executing other processing without waiting for the completion of input / output processing of the device.

The I / O controller and the device are connected by a plurality of channel paths, and the I / O commands and data transferred between the I / O controller and the device are transferred through this channel path. . The channel paths and devices can be connected in a one-to-one, one-to-many, and many-to-one connection form. Also, the I / O controller can handle multiple I / O requests at the same time. In such a situation, even if the higher-level device issues an I / O request, the command or data may not be transferred because the channel path is in use. As a measure against this problem, in the prior art device, when the input request transferred from the host device is registered in the input request queue, the input request is used as described in, for example, Japanese Patent Laid-Open No. 60-183660. It determines if a possible channel path is free, and if that path is free, it takes one I / O request using that path from its input queue and processes it. Alternatively, the same thing was done when any of the currently used channel paths became empty.

In order for the I / O controller to process one I / O request, after dequeuing one I / O request using the channel path in the idle state from the queue, (1) the input Read one channel command word in the channel program based on the address specified by the output request, and (2) transfer it to the disk controller,
(3) The above steps (1) and (2) are repeated each time the disk controller notifies that the command word has been executed.

By such processing, the execution of the input / output request by the input / output control unit ends when all of the set of channel command words have been executed.

In the prior art, the above-described operation is performed every time a new input / output request is input from the host device or one channel path becomes idle.

(4) Further, when the input / output request is a data write request, the main memory address designated by one of the set of channel command words is used,
The write data was read from the main storage device to the buffer in the input / output control device, and then the data was transferred to the disk control device.

[0009]

In the above-mentioned conventional method, the I / O requests are fetched from the queue one by one and processed. Therefore, various overheads are incurred in processing each I / O request.

These overheads will be described more specifically. There are two types of overhead.

One is a retrieval overhead of channel command words and data stored in the main storage device. When the input / output processor executes input / output, it is necessary to fetch the input / output command and data stored in the main storage device by the user or the operating system into the input / output processor. More specifically, it is as follows. The following process shows the operation of repeatedly executing one input / output request composed of a plurality of channel command words as long as the input / output request exists.

(1) Judgment of presence / absence of input / output request (2) Extraction of input / output request (3) Invalidation of extracted input / output request (4) Main storage device address in which channel command is stored from input / output request (5) Retrieving one channel command word from the main memory (6) Repeating (5) until one input / output request is completed (7) To process the next input / output request Return The above process is composed of a plurality of micro program modules. Therefore, in order to execute the input / output processing, it is necessary to perform processing across a large number of micro program modules, and sometimes across a plurality of microprocessors. These processes are one of the factors of performance degradation.

The second type of overhead is the overhead that occurs when commands and data are transferred from the I / O processor to the disk controller. Specifically, it is as follows and is a process executed between the above (5) and (6).

(A) Analyzing the channel command fetched from the main storage device (b) Judging whether it is a command to the disk controller or a command to the I / O processor, and if it is a command to the disk controller, the disk for which the command is specified Transfer to controller (c) Execute command if it is for I / O processor (d) Repeat (a) to (c) until one I / O request is completed. This is an overhead that occurs because processing is performed in synchronization with control. Disk controller is SEEK, SEARCH, RE
Although a series of processes such as AD / WRITE is performed, these commands are transferred from the input / output processor to the disk control device one by one. However, the SEARC
The H command is a process for determining whether or not the disk head has reached a predetermined one, but when the I / O processor transfers this command to the disk controller, it starts executing the next channel command. As it is, it does not operate normally. In other words, at this point the next RE
If the AD / WRITE command is executed, READ / WEIT will be executed for the current position of the disk head, and thus illegal data will be read or written. Therefore, place the TIC command between the SEARCH command and the READ / WRITE command, and
At the position where the target data exists by the H command, it is necessary to continue processing the SEARCH command until the disk arrives. During this time, the I / O processor must execute a channel command dedicated to the I / O processor, which originally has no direct relation to the command to the disk controller.

The conventional method has advantages that it is easy to control and that performance in a relatively low load environment does not significantly affect. However, as the channel path transfer becomes faster, the overhead ratio becomes relatively large. For example, conventional channel path transfer time: 1 ms, overhead 0.
Assuming 5 msec, the overhead ratio is 33%. However, if the overhead is constant and the channel path transfer rate is improved by one digit, the high-speed channel path transfer time is 0.1 msec and the overhead is 0.5 msec, even if data of the same data length is transferred. The ratio will be 83%. That is, as the channel path transfer time becomes shorter, most of the channel path use time becomes the overhead time.

Further, it is advantageous that the number of channel paths connected to the device is reduced as much as possible because the operation is easy and the device can be flexibly added. In a user environment that demands such merits, the number of queued I / O requests increases, and the above problem becomes more prominent.

An object of the present invention is to provide an input / output control method and device for reducing the overhead caused by command transfer between the input / output control device and the external storage control device.

Another object of the present invention is to provide an input / output control method and device which involves reading individual commands from the main memory.

[0019]

According to the present invention, a channel program specified by at least one output request issued from a higher-level device to an external storage device is read and sent to the external storage control device.

The external storage controller stores the channel program and executes the commands contained in the program under the control of the external storage controller. In a more desirable aspect of the present invention, a plurality of channel programs are collected and transferred from the input / output control device to the external storage control device.

[0021]

As described above, in the example of the present invention, since the execution of the channel program is controlled by the external storage controller, the overhead required by the command transfer between the I / O controller and the external storage controller, which has been conventionally required, can be minimized. High throughput can be obtained.

Further, since a plurality of commands belonging to the same channel program are fetched together in advance, the overhead associated with command reading is reduced as compared with the conventional case where these commands are fetched successively.

Further, when a plurality of channel programs are collectively fetched from the main memory and transferred to the disk controller, the command read overhead and the transfer overhead are further reduced.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A data input / output control method according to the present invention will be described in detail below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing the overall configuration of an embodiment of an input / output subsystem to which the present invention is applied. The input / output subsystem mainly includes an input / output control device or input / output processor 101, an external storage control device or disk control device 131, an external storage device such as a disk device 132, and a main storage device 121. In the input / output subsystem according to the present invention, when an input / output request 130 is issued from a higher-level device (not shown), the input / output processor 101 performs an input / output request acceptance process, and then the main storage device 120 and the disk controller. Device 13
Input / output is achieved by performing data transfer with 1. The input / output processor 101 operates independently of a host device that issues an input / output request, and is composed of an input / output control processor 102 and a plurality of channel control processors (or channel devices) 108. According to the request, input / output control of data transferred between the disk device 132 and the storage device 121 is performed. The input / output processor 101 and the disk control device 131 are connected by a plurality of channel paths 142, and each channel control processor 108 is connected to the disk control device 131 via one channel path. The input / output request control processor 102 includes a main memory transfer control unit 134 that controls data transfer with the main memory device 121, a control processor 136, and a memory 138. Memory 138
The channel path control table 103 and a plurality of microprograms 1060 are stored in, for example. The control processor 136 executes the microprogram 1060 stored in the memory 138 and also controls the control table 10
The reception control of the input / output request 130 and the like are performed while the reference update of 3 is performed. The channel control processor 108 includes a main memory transfer control unit 135, a control processor 137, and a memory 139.
Composed of. These channel control processors 10
8 transfers data with the disk controller 131.
The memory 139 stores a command / data buffer 113 for temporarily storing commands and data, a plurality of microprograms 1090, and the like. The disk control device 131 comprises a plurality of disk control processors 133 each composed of a control processor 140 and a memory 141. Each disk control processor 133
Indicates that the input / output processor 101 has a plurality of channel paths 14
The command input from the I / O processor 101, which is connected via the I / O processor 2, is analyzed, and the disk I / O is performed on the n disk devices (n: integer of 2 or more) 132 (132-1 to 132-n). I will go. In the memory 141, a command / data queue 1 for temporarily storing commands and data transferred from the input / output processor 101.
15, channel path control table 103 ′, disk control table 118, a plurality of microprograms 106
0'and the like are stored.

Next, FIG. 2 shows each control processor 1 of FIG.
36, 137 and 140 show microprogram groups executed. The control processor 106 in the I / O request processor 101 uses the channel path selection / I / O request registration unit 1
04, collective control unit 106, channel busy detection unit 10
5. The microprogram such as the input / output request batch fetch unit 107 is executed. Each channel control processor 10
The control processor 137 in 8 includes a command batch fetch unit 109, a data batch transfer unit 110, and an input / output request analysis unit 1.
11, a microprogram such as the data transfer control unit 112 is executed. The control processor 140 in the disk control device 131 executes a microprogram including a batch control unit 106 ', a data transfer control unit 114, a command processing unit 117, and a channel busy detection unit 105'.

Further, the main storage device 121 is pointed to by a plurality of input / output request queues 122 for holding the input / output requests 130 transferred from a host device (not shown), and the input / output request queue 122. Channel program 1
Storage areas 23, 124, 125 and data areas 126, 127, 128 for storing data associated with the respective channel programs are secured. Each channel program consists of multiple channel command words.

First, the outline of the input / output processing in this embodiment will be described. FIG. 3 shows a processing flow in the input / output processor 101.

First, the input / output request 130 issued from the host device is accepted by the input / output request control program 102 (step 204), and then the channel path 142 is passed from the content of the accepted input / output request 130. Then, it is determined whether data transfer is to be performed (step 205). This determination is performed by searching the channel path control table 103. After that, the input / output request 130 accepted in step 206 is registered in one of the input / output request queues 122. Next, the I / O request control processor 102 detects whether the channel path selected in step 205 is currently being used by another data transfer (step 207), and if it is being used (busy) by another data transfer. For example, it waits until the data transfer is completed (step 210). The waiting for the completion of the free path is analyzed when the data transfer in the channel path is completed and the free path report is received, and if the channel path is not busy in step 207, the process proceeds to step 208. In step 208, it is determined whether or not there is already a wait for an I / O request that uses the same path in the I / O request queue 122. If there is no wait, then waiting for registration is performed by waiting for registration. (Step 209). The I / O control processor path then proceeds to step 208 when the I / O instruction using that channel path is registered at step 208.
Then, among the I / O requests registered in the I / O request queue 122, a plurality of I / O requests that use the channel paths in the empty state are extracted, and in the next step 212, commands or commands corresponding to the respective I / O requests are output. The data is collected, read from the main storage device, and transferred together to the disk control device 131. The disk control unit 131 holds these commands and data in a queue, and the command processing unit 117 executes each command at an appropriate timing. The major difference of the present embodiment from the conventional one is that when any channel path is idle, a plurality of I / O requests that use that path, a plurality of channel programs specified by them, and A point at which write data designated by a part or all of them are collectively fetched, and those are taken out by the disk controller 131
That is, the transfer is performed collectively using the channel path, and the execution timing of these commands is determined in the disk control device 131. This allows
It is possible to reduce the channel program, the overhead associated with reading data, the overhead associated with the transfer of channel command words and data between each channel control processor and the disk controller, and to realize high throughput.

The present embodiment will be described in more detail below.

First, the input / output request issued from the host device in this embodiment will be described with reference to FIG.

FIG. 4 shows an example of a program 301 for inputting / outputting a file stored in a device, and a host device (not shown) for actually inputting / outputting the file input / output to / from the device. FIG. 3 is a schematic view showing the operations (302 to 304) of the operating system executed in 1. The input / output program 301 describes a general file input / output program. File input / output is performed in the READ part, and pre-processing and post-processing (OPEN / CLOSE) for performing input / output before and after the READ part are included.
In the READ part, a data area storing data as parameters and other information are designated. Upon receiving the READ portion of the input / output program 301, the operating system is activated. In step 302, a channel program word is created. The channel program is a sequence of channel command words for which the operation required of the input / output processor 101 is described, and the input / output request for the disk is stored in this. In step 303, an input / output request for requesting the input / output processor to execute the channel program is issued. At this time, the input / output request specifies, as a parameter, the identifier of the device to perform the input / output operation or the input / output request block address. The address where the execute all channel program is stored can be known from the I / O request block address. And step 30
At 4, the input / output process is waited for. Completion of the input / output processing is realized by returning an interrupt from the input / output processor 101 to the host device. This interrupt cancels the I / O completion wait and continues the processing of the I / O program 301.

An example of a channel program which is an interface program between the input / output processor and the host device is shown in FIGS.

5 and 6 show two types of channel programs used for input / output processing. FIG. 5 (A),
The first type of channel program shown in (B) is a format for controlling the disk head by a command,
401 to 408 are READ processing, 409 to 416 are WR
The channel program of ITE processing is shown. SEE
K (401) is for positioning the cylinder head to the target record on the disk.
TOR (402) is for positioning the cylinder head to the sector of the target record. SEARCH
The ID EQUAL (403) is an instruction to confirm the target record, and the TIC (404) is usually the SEA.
It means a jump operation to the RCH ID EQUAL (403). SARCH ID EQUAL (403)
And TIC (404) are paired, and the SEARCH ID is set until the condition is met and the target record is confirmed.
Repeat EEQUAL (403). SEA
When the condition is met in RCH ID EQUAL (403) (the target record position is reached), TIC (40
In step 4), control is transferred to READ (405). READ (405) means reading of data of the length indicated by the data length (406) from the current disk head position. The read data is stored in the memory indicated by the main storage address (407). WRIT
In the E processing (409 to 416), READ (405) is also RI.
The other format is the same except that the TE (403) is changed and the main storage address is changed to an address indicating the storage area of the write data.

However, the operation is such that at the time of READ, the data area (4) specified by the channel program (401-407) is specified.
The result is stored in (08), whereas in WRITE, the upper device starts executing the channel programs (409 to 415) after storing data in the data area (416).

The second type channel programs shown in FIGS. 6A and 6B are simple formats, unlike the first type channel programs. The first type of channel program controls the disk head within the channel program (401-407, 409-40
5), the second type of channel command word is a request (READ, WRIT) to the disk.
E) and the target record position, SEEK,
SET SECTOR, SEARCH IR EQA
Disk controller (1
31). Reference numerals 417 to 420 are channel programs for performing READ operation, and 422 to 425 are WRITE.
It is a channel program that operates.

This embodiment can be applied to the above two types of channel programs.

FIG. 7 shows a schematic diagram of an example of a disk device connection configuration. There are a plurality of channel control processors 108 in the input / output processor 101, and each corresponds to one channel path. In this embodiment, the channel path 1
Suppose there is ~ 4. A plurality of disk devices 132 are connected to the disk control device 131. Software that issues I / O requests to these disk devices 132 generally has a unique name in the system corresponding to each disk device 132, for example, VOL1.
Input and output by specifying VOL4. In FIG. 7, channel path 1 and channel path 2 are associated with VOL1 and VOL2.
Data is input / output via any of the above. Similarly, data input / output is performed with respect to VOL3 and VOL4 through either channel path 3 or channel path 4. Input / output is normally performed via a channel path (empty path) where data is not transferred. In this way, the throughput can be increased by connecting a plurality of channel paths to the same disk.

Next, main resources used by the input / output processor will be described. The important resources used in the present invention are the I / O request queue 122 and the channel path control table 103 shown in FIG. The channel path control table 103 is used to manage the plurality of channel control processors 108 described in FIG. Further, the input / output request queue 122 is used to temporarily hold an input / output request sent from the host device.

First, the structure of the channel path control table 103 will be described with reference to FIG. The channel path control table 103 has a device identifier 60 for each device.
1. I / O request queue identifier 602 that holds I / O requests for each device 602 Number of waiting I / O requests registered in each I / O request queue 603; Channel number currently available to access each device (That is, the channel control processor number) 4 and a field for storing the channel device status 605.

Normally, the device identifier 601 is a value set by the system administrator for each device when the system is constructed in order to identify each input / output device. This value is unique in the system, and the same device identifier is never set for different devices. Therefore, when the device identifier is designated, the device corresponding to it is uniquely determined. This value is also specified when the software issues an input / output request to the input / output processor 101.

The input / output request queue identifier 602 is for identifying a plurality of input / output request queues 122. The input / output request queue 122 may basically have any unit. I / O request queue 12
The structure of 2 and the holding unit will be described in detail later. A field 603 is a value indicating how many input / output requests are registered as waiting input / output requests for each input / output request queue 122. A field 604 indicates an available channel device, and a plurality of channel paths are assigned to one device as described in FIG. Here, the available channel path indicates a channel path that may be used for data transfer if it is free. This available channel path (available channel device) is
Set by the administrator when building the system. For example, it is common for an administrator to connect more paths to a disk control device to which a disk device that is likely to be heavily loaded is connected. The channel device status field 605 indicates whether the channel path is busy. In the figure "BU
SY "indicates that the target channel path is currently used for processing another I / O request, and" FREE "indicates that it is not used. For example, it is identified by the device identifier" 10 ". There are three channel paths (channel devices: "1", "2", "1"
0 ”) is assigned, and the channel paths of the channel devices“ 2 ”and“ 10 ”are currently in use. The input / output request queue 122 is collectively managed by the identifier“ 1 ”. The number of I / O requests waiting for a request is 5. As another allocation method of the I / O request queue 122, two I / O request queues 122, such as the disk device 132 identified by the device identifier “20”, are used.
In some cases, (input / output request queue identifiers: “2”, “3”) are assigned. This is the channel device 10
It is shown that each 8 has an input / output request queue 122.

Next, referring to FIG. 9, the input / output request queue 12
The input / output request held in 2 will be described. Here, the input / output request queue 122 indicated by the input / output request queue identifier “1” will be described as an example. Each I / O request has four fields 701 to 704.

The field 701 holds the start address of the channel program 123, 124 or 125 (FIG. 1) designated by each input / output request. Field 702
Holds the identifier of the device used by each I / O request.
The field 703 indicates the data length of the data transferred by each input / output request. A field 704 indicates the type of each input / output request, for example, “READ” indicating data transfer from the device to the main storage device, and conversely “WRITE” indicating data transfer from the main conspirator device to the device. is there. As shown in FIG. 9, there are a plurality of input / output request queues 122. The input / output request queue 122 is associated with the channel path control table 103 via the input / output request queue identifier. Although the input / output request queue 122 is placed on the main storage device 121 in this embodiment, it is possible to improve the processing performance by placing it in the input / output processor 101 if possible.

Next, referring to FIG. 10, the input / output request queue 1
The 22 management units will be described.

The input / output request queue 122 can be set in arbitrary units. Basically, it is desirable to place them at locations where access is frequent and there is a high possibility that performance will be a bottleneck. The arrangement 1 shown in FIG. 10A is, as an example, the input / output request queues 122a and 122 corresponding to the two disk control devices 131a and 131b, respectively.
b is provided. As a case where such an arrangement is effective, it is conceivable that each disk control device 131a, 131b manages many disk devices.

Arrangement 2 shown in FIG. 10B shows an arrangement in which the input / output request queues 122c and 122d are arranged for each disk device. Unlike the arrangement 1, the arrangement 2 has an input / output request queue for each disk device regardless of the number of disk control devices 131. Such an input / output request queue management unit is effective when using a device that can be accessed frequently. For example, like a disk array device 132 ', the software logically looks like a single disk device, but inside the device it is a device that can simultaneously access a plurality of disk devices 815, 816, 817, or a semiconductor memory or the like. It is conceivable that the configured device can expect very fast response.

In the arrangement 3 shown in FIG. 10C, the input / output request queues 122e and 122f are arranged for each channel path. Such an arrangement is effective when it is necessary to process input / output requests with high frequency using a small number of input / output paths, or when efficiently processing short data using a high-speed channel.

Although the present invention can be applied to the above various arrangements, it is assumed below that the arrangement 3 is used for speeding up.

Next, the operation of the control processor 136 in the input / output processor 101 will be described using the above resources. FIG. 11 shows a flow of processing in the channel path selection / input / output request registration unit 104. When the input / output request 130 is sent from the host device, the control processor 136 first activates this process and accepts the request (step 901). Upon receiving the input / output request 130, the channel path selection / input / output request registration unit 104 searches the status field 605 in the channel path control table 103, and the available channel device corresponding to the device identifier designated by the input / output request. 108
Is currently available (step 902). The channel busy detection unit 105 constantly monitors the operation of the channel control processor 108,
The status field in 3 is updated. As a result of the investigation in step 402, if there is a channel device 108 whose channel device status is “FREE (empty)”, the I / O request queue 122 corresponding to it is selected. When there is no channel device 108 whose channel device status is "FREE", the I / O request queue identifier corresponding to the channel path with the smaller number of waiting I / O requests 130 is selected. The number of waiting requests can be obtained by referring to the number of waiting requests field 603 of FIG. However, the selection based on the number of waiting I / O requests 130 is
This is possible only when a plurality of I / O request queues 122 are assigned to the device specified by the received I / O request, and in other cases, selection by the number of waiting I / O requests 130 is not necessary. In step 904, the device identifier, channel command word start address, transfer data length, and request type are registered in the input / output request queue 122 corresponding to the input / output request queue identifier obtained in step 903. After that, the value of the waiting request number field 603 of the channel path control table 103 is incremented (step 905), and a start request is issued to the collective control unit 106 (step 906). At this time, the batch control unit is notified of the newly registered input / output request.

The processing in the collective control unit 106 is one of the features of the present invention, which will be described below with reference to FIG.

There are two types of activation triggers for the collective control unit 106. One is the activation request from the channel path selection / I / O request registration processing unit 104 described above, and the other is the data transfer processing unit 1 executed by the channel control processor 108.
12 is a start request.

Channel path selection / I / O request registration unit 10
When receiving the activation request from the communication controller 4 (step 1001), the collective control unit 106 inquires of the channel busy detection unit 105 whether or not the channel path can be used (step 10).
2). Here, the channel busy detection unit 105 refers to the channel path control table 103, and detects whether the channel path 142 corresponding to the device identifier designated by the received input / output request can be used. Then, the result is reported to the collective control unit 106. Next, the collective control unit 106 determines that the corresponding channel path 140 is “B”.
If it is "USY", the process is terminated, and if it is "FREE", the process proceeds to the next step (step 1003) If the corresponding channel path 140 is "FREE" in step 1003, the collective control unit 106 Searches the channel path control table 103 to obtain the identifier of the input / output request queue holding the input / output device request for the device using the channel path (step 1004). The processing unit 107 is instructed to take out all the I / O requests for the device that uses the channel path registered in the specific I / O request queue 122 corresponding to the previously obtained I / O request queue identifier ( (Step 1005). As assumed in this embodiment, each input / output request queue has one If it is provided corresponding to the channel path, it is sufficient to request the extraction of all the I / O requests registered in the I / O queue having the I / O request queue identifier obtained in step 1004. The corresponding wait request number field 603 of the control table 103 is set to zero, and the channel device status field 605 is set from "FREE" to "BUS".
Y ″ (step 1006). Thereafter, the input / output request batch fetch processing unit 107 fetches a plurality of I / O requests registered in the specific I / O request queue, and the batch control unit 106 fetches these. The plurality of input / output requests are sent to the input / output request analysis unit 111 of the channel control processor 108 provided for the channel path (step 1007).
As shown in FIG. 9, a channel program start address and other information are sent as each input / output request.

The activation request from the data transfer control unit 112 of any channel control processor, which is another activation to the collective control unit 106, is generated at the time when the data transfer in any channel path is completed. At this time, the collective control unit 106 is sent with information as to which channel path the data transfer is completed. Upon receiving the activation request from the data transfer control unit 112 in step 1008, the collective control unit 106 searches the channel path control table 103 based on this information, and inputs / outputs waiting for data transfer to the corresponding channel path. Whether or not there is a request is checked, and if the result is that there is no waiting for an input / output request waiting for data transfer, the process ends, otherwise the process moves to step 1002 and the same process as described above is performed (step 1009).

The input / output request analysis unit 111 of the channel control processor 108 analyzes a plurality of input / output requests sent from the collective control unit 106 and determines whether they are a data read request or a data write request to the device. . These determinations are made by referring to the field of the request type 704 (FIG. 9) in the input / output request queue 122. After that, the command batch fetch unit 10
9 is started, and the channel program specified by those input / output requests is fetched. The plurality of I / O requests sent from the batch control unit 106 hold the start addresses of the channel programs used by each, and the command batch fetch unit 109 uses these start addresses from the main storage device 121. A plurality of channel programs 123, 124 or 12 designated by these input / output requests
5 is sequentially read and transferred to the command / data buffer 113. After that, the input / output request control unit 111 activates the data batch transfer unit 110, and the command batch fetch unit 1
The write data is read from the main memory on the basis of the main memory address designated by the command in the channel program fetched by 09, and the command / data buffer 11 is read.
Take in 3. When there are a plurality of input / output requests for writing data, the write data designated by the input / output requests are sequentially read from the main storage device 121.

The plurality of channel programs and write data thus read are stored in the command / data buffer 113 as shown in FIG. For simplification, the channel program is shown as a command and the write data is shown as data in the figure. Specifically, following the channel program for each input / output request, when the input / output request requests data writing, write data is stored. Commands / data 1405, 1408 are examples of such programs or sets of programs and write data. Each command / data 1405 or 1408 is preceded by a command identifier 1403 or 1406 and a command / data length 1404.
Or 1407 is added. The command identifier 1403 or 1406 uses an identifier of a device controlled by a channel program stored subsequently. The command / data length is the data length of the channel program that follows it or a set of it and write data. Before multiple sets of data for such multiple I / O requests,
A data identifier 1401 and a total transfer data length 1402 are added as a header. As the data identifier 1401, in this embodiment, the identifier of the input / output request queue from which the aforementioned plurality of input / output requests are extracted is used. These data identifiers 14
01, total transfer data length, command identifier 1403, 14
06, the command / data length is the input / output request control unit 111
Written by.

As described above, in this embodiment, the I / O request unit 111, the command batch fetch unit 109, and the data batch transfer unit 119 are activated for a group of a plurality of I / O requests. There is little overhead of starting and ending.

Unlike the prior art, it is necessary to take in a plurality of commands and the data associated with them, so that the capacity of the command / data buffer 113 must be made larger than before. This capacity is preferably a value obtained by multiplying the number of input / output request queues 122, the average queuing length of each input / output request queue 122, and the average data length of one input / output request. Due to the implementation of the output processor, there is a possibility that it can only have a smaller amount of memory. In that case, I / O request queue 1
Command / data buffer 113 for all requests in 22
There are cases where it cannot be stored in. In such a case, control may be provided to fetch as many input / output requests as can be stored in the free area of the command / data buffer 113. These controls are achieved by returning the input / output request that could not be stored to the input / output request queue 122 when the command batch fetch unit 109 or the data batch transfer unit 110 is executed. At this time, the predetermined input / output request queue 1
Since there is a possibility that a new I / O request is stored in 22, the I / O order can be maintained by queuing at the head of the I / O request queue 122 (position that is taken out earliest next). it can. Also, the value of the waiting request number field 603 of the channel path control table 103 is set to
It is necessary to add the number of input / output requests that could not be stored. Further, a plurality of I / O requests stored in the command / data buffer 113 are sent to the command / data buffer 11
It is necessary to recognize in which position of 3 the data is stored. Therefore, the batch control unit 106 can be realized by replacing the channel command word start address 701 stored in the data field extracted from the input / output request queue 122 with the address in the command / data buffer 113. This information is used by the disk controller 13
Save the command and data to 1 until the transfer is completed /
It is possible because it is managed. Furthermore, since a plurality of commands and data or all of them are collectively transferred to the disk control device 131, the queue 116 in the disk control device 131 is
It can also be used in cases where it cannot be stored due to the capacity of. That is, since the capacity of the queue 116 in the disk control device 131 is limited, the number of commands and data that can be queued is also limited. At this time, by notifying the command that cannot be stored from the disk control device 131, only the command that could not be stored in the queue 116 in the disk control device 131 can be re-registered in the I / O request queue 122.

When the transfer of a plurality of channel programs and write data to the command / data buffer 113 is completed, the channel control processor 108 activates the data transfer control unit 112. Data transfer control unit 1
12 is thus the command / data buffer 11
The data transfer control unit 11 in the disk control device 131 stores the data composed of the respective units 1401 to 1408 stored in FIG.
4, the channel control processor 108 to which the data transfer control unit 112 belongs in the channel path group 142.
-Send as one transfer data via the channel path connected to i. When the command / data transfer with the disk control device 131 is completed, the data transfer control unit 112 notifies the batch control unit 106 of the end together with the channel device number of the channel control processor 108 used for the transfer.

Collective control unit 10 of disk control device 131
6 ′ and the channel busy detection unit 105 ′ respectively include a collective control unit 106 in the input / output processor 101,
And the same processing as that of the channel busy detection unit 105 is performed. Further, the channel path control table 103 'is
It has the same contents as the channel path control table 103.
There are two types of command / data queues, and a plurality of command / data queues 116 are provided, which are used at the time of a start request from the input / output processor 101, and are sent in batch from the input / output processor 101 and at the time of writing. Stores write data. On the other hand, a plurality of command / data queues 115 are provided and hold the execution result information transferred to the input / output processor 101 and the read data at the time of reading when the input / output processing is completed. There are a plurality of command / data queues 115 and 116, respectively. Ideally, it is desirable to have the same number as the disk devices 132.

The data transfer control unit 114 in the disk controller 131 selects the command / data queue 116 in which the data sent via the channel path should be stored, removes the headers 1401 and 1402, and 1403-
Data consisting of 1408 is stored in the command / data queue 116.

FIG. 13 shows the disk device control table 1
The structure of 18 is shown. A field 1101 holds a disk device identifier, a field 1102 holds a command / data queue identifier, a field 1103 holds the number of processing waiting requests, and a field 1104 holds a disk device status. From the disk device control table 118, it is possible to know the status of the disk device 132 and the command / data queues 115 and 116 corresponding to each disk device 132. The command processing unit 117 refers to the disk device control table 118 to perform processing.

FIG. 14 shows a flow of disk command processing in the command processing section 117. There are two kinds of activation triggers for the disk command processing, one is based on the activation request from the data transfer control unit 114, and the other is based on the input / output end report from the disk device 119.

When the activation request is received from the data transfer control unit 114 (step 1201), the command processing unit 117 is executed.
Takes out one of the commands and data registered therein from the command / data queue 116 corresponding to the disk device for which the input / output is requested, and registers the one registered at the beginning, and designates it by the command identifier preceding the command. The target disk is activated (step 1202). By this activation, the process of FIG. 25 is started in the background. This activation uses the channel command words (1210 to 1213). This channel command word (1
210 to 1213) are transferred from the input / output processor 101. As described above, since only the commands necessary for controlling the disk device 132 are transferred to the disk control device 131, it is simplified as compared with the format stored in the main storage device. Specifically, it is the reduction of TIC commands. Therefore, this TIC
The main purpose of this process is to perform the same operation as the command. Step 1214 detects the end of the channel command word. In step 1215, the operation of extracting one channel command word is performed. In step 1216, it is determined whether or not the channel command is SEEK, and if so, the command is transferred to the disk device 131, the end thereof is waited for (step 1224), and the process returns to step 1214. In step 1217, the channel command is SEA
It is determined whether it is the RCH, and if so, the command is transferred to the disk device 131, and waits for its completion (step 1
225), and returns to step 1214. Step 1218
Then, it is determined whether the command is SEARCHID EQUAL, and if so, the command is sent to the disk device 131.
Transfer to. Then, it is judged whether or not the execution result of the command satisfies the condition of the command (step 122).
6) If the conditions are not satisfied, step 1222 is re-executed. If it is satisfied, step 1214 is executed. By this processing, the TIC command, which is conventionally performed on the input / output processor side, can be realized by the disk control device 131. In step 1219, it is determined whether the channel command is READ, and if so, the command is transferred to the disk device 131, the completion of the command is waited for (step 1227), and the process returns to step 1214. At this time,
"BUSY" is written in the corresponding disk device status 1104 of the disk device control table 118 (step 1203), and the next disk activation request is waited for (step 1204).

On the other hand, when the I / O completion report is received from the disk device 119 (step 1205), the command processing section 117 sends the read data or the return information to the command / data queue 115 corresponding to the disk device for which the I / O completion report was issued. Set (step 1206). Then, the collective control unit 106 'is notified of the queuing (step 1207). In addition, in the collective control unit 106 ′ that has received the notification of queuing, the input / output processor 101
The same processing as the collective control unit 106 (processing starting from step 1001 in FIG. 12) is performed, and the operation of transferring data or return information to the input / output processor is started.

Next, one data and command at the head are extracted from the command / data queue 116 corresponding to the disk device for which the I / O completion report has been issued, and step 12
The process proceeds to 02 to activate the target disk device (step 1208). Then, the disk device control table 118
The corresponding disk unit status 1104 of “BUS
Y ”is written (step 1203). If there is no waiting request registered in the command / data queue 116 in step 1208, the corresponding disk unit status 1104 of the disk unit control table 118 is written.
Then, "FREE" is written as the disc status.

By performing the disk command processing as described above in parallel for each of a plurality of command / data queues, the operation as shown in FIG. 15 can be realized.

In FIG. 15, the disk devices 1307 and 13 are shown.
08, the command / data queue 1301 is commonly used, and the disk devices 1309 and 1310 independently use the command / data queues 1302 and 1303. Disk command processing 1304, 1305, 13
In 06, the corresponding command / data queue 1
It is checked whether there is a wait in each of 301, 1302, and 1303, and if there is a wait, the corresponding disk device is activated. By performing such control, the busy rate of each disk device can be increased. In particular, if one disk device is used to use one command / data queue like the disk devices 1309 and 1310, the busy rate can be further increased. For this purpose, the data transfer control 114 registers the plurality of channel programs transferred to the command / data queue in the same command / data queue when registering the plurality of channel programs in the command / data queue. It is desirable to register a plurality of channel programs for controlling different external storage devices in different command / data queues as much as possible.

In FIG. 15, the disk devices 1307 and 13 are used.
08, the command / data queue 1301 is commonly used, and the disk devices 1309 and 1310 independently use the command / data queues 1302 and 1303. Disk command processing 1304, 1305, 13
In 06, the corresponding command / data queue 1
It is checked whether there is a wait in each of 301, 1302, and 1303, and if there is a wait, the corresponding disk device is activated. By performing such control, the busy rate of each disk device can be increased. In particular, if one disk device is used to use one command / data queue like the disk devices 1309 and 1310, the busy rate can be further increased. To this end, the data transfer control 114 registers a plurality of channel programs controlling the same external storage device in the same command / data queue when registering the plurality of channel programs transferred thereto in the command / data queue, It is desirable to register a plurality of channel programs for controlling different external storage devices in different command / data queues as much as possible.

The channel program processing described above will be described more specifically.

First, the processing of the channel program corresponding to the WRITE request will be described with reference to FIGS.

In FIG. 20, a channel program (123) indicating a WRITE request to a certain disk device 132 (for example, 132-1) has another input / output request (WRITE, READ) to the same disk device as the WRITE request.
Disk controller (1 regardless of request)
31) shows the flow until it is transferred to 31). Input / output request batch fetch unit (1 in the input / output processor (101)
07) takes in one (for example, 122-1) or a plurality of input / output requests in the input / output request queue (122) stored in the main storage device (121) collectively, that is, collectively. Thus, for example, a plurality of channel programs (123, 124, etc.) pointed to by a plurality of input / output requests s that are collectively fetched are fetched. At this time, remove the channel program that is not directly related to the disk I / O control included in the channel program,
For example, in this example, the TIC is an input / output processor (10
It is for control of 1) and is removed. But,
It need not be removed in the WRITE format of channel command word 2 in FIGS. 6A and 6B. Further, the data batch fetch unit (110) fetches the data (126) if the input / output request is a WRITE process. These plural channel programs and data are grouped as one data (1803 to 1810), and the data identifier 1801 of these grouped data and the total data transfer length L of the channel command and data after grouping are shown. Data (1
802) as a header is transferred to the disk control device (131) by the data transfer control unit (112) and corresponds to the disk device 132 (for example, 132-1) via the disk transfer control unit 114. It is stored in one of the command / data queues 116. Therefore, the command processing unit 117 writes the data based on the WRITE request in the corresponding disk device (for example, 132-1).

FIG. 21 shows one WR issued in FIG.
According to the ITE request (1803 to 1809), the data (1809) has a predetermined disk device (for example, 132-1).
And write the end report to the input / output processor (10
The process of transferring to 1) is shown. Command processing unit 11
7 is a WRITE end result (1908) indicating whether the processing is normally ended or abnormally ended as a result of the data being output to the corresponding disk device (for example, 132-1) by the WRITE request (1803 to 1809). ) Is added to the command identifier (1907) and stored in the command data queue (for example, 115-1) corresponding to the disk device (for example, 132-1). Disk controller (1
The batch control unit (106) of 31) thus stores the WRITE end result stored in the command data queue (115-1) and other input / output results (WRITE, READ end result) corresponding to the same disk device (132-1). From one or more input / output end results (1906 to 190)
8) is taken in, and the data identifier (1901) is added,
The data transfer control unit 114 adds, as a packet, the data (1802) indicating the total data transfer length L together with the I / O end result that is collectively fetched in this way to the I / O processor (106) as a packet. Forward.

Here, the command identifier 1904 and the like are added by the collective control unit 106 '.

The I / O processor (101), to which this packet is sent, transfers the batched end report to the host processor corresponding to a unit of I / O request or a unit of I / O request in the form of being kept in a batch. To do.

Next, the processing of the channel program corresponding to the READ request will be described with reference to FIGS.

In FIG. 22, a channel program (123) indicating a READ request to a certain disk device 132 (for example, 132-1) has another input / output request (regardless of WRITE or READ request) to the same disk device as the READ request. Together with the disk controller (13
The flow until it is transferred to 1) is shown. I / O request batch fetch unit (10) in the I / O processor (101)
7) fetches one or a plurality of input / output requests in the input / output request queue (122) stored in the main storage device (121) at once. In this way, for example, a plurality of channel programs (123, 124, etc.) pointed to by the input / output requests that are collectively fetched are fetched. At this time, the channel program included in the channel program and not directly related to the disk input / output control is removed. For example, in this example, the TIC is an input / output processor (1
It is removed for control of 01). However, in FIG.
6B channel command word 2 WRITE format does not require removal processing. Unlike WRITE processing, READ
Since data does not yet exist in the processing, it is necessary to remember where in the main storage device (121) the input data should be written, so the main storage address (200
9) is also added. Further, the data batch fetch unit 11
For 0, if the input / output request is the WRITE processing, the data (126) is fetched, but nothing is done in the READ processing. These plural channel programs or data are collected as one data (2003-2
010), and further, a data identifier (2001) and a total data transfer length L of the channel command s and the data after grouping.
Which has been added as a header to the disk device 132 (for example, 132-1) via the disk transfer controller 114 is transferred to the disk controller (131) by the data transfer controller (112). It is stored in the corresponding command / data queue 116. Therefore, the command processing unit 117 reads data from the corresponding disk device (for example, 132-1) based on the READ request.

FIG. 23 shows one RE issued in FIG.
Data (211) according to AD request (2003 to 2009)
2) is transferred from a predetermined disk device (for example, 132-1) and the completion report is transferred to the input / output processor (101). The command processing unit 117 is RE
As a result of the data being output to the corresponding disk by the AD request (2003 to 2009), the READ end result (2
110) and data (2112) have command identifier (21
09) is added to the disk device (for example, 132-
Command data queue corresponding to 1) (for example, 115-1)
To store. The collective control unit 106 'of the disk control device (131) thus stores the READ end result stored in the command data queue 115-1 and other input / output results (READ, WR) corresponding to the same disk device 132-1.
One or more input / output end results (2108 to 2112) and main storage address 2114 from the ITE end result)
Data transfer control is performed by adding a data identifier (2101), a result of input / output completion thus collectively received, and data (2, 02) indicating the total data transfer length L of the data as a header. The packet is transferred from the unit 114 to the input / output processor (106).

Here, the command identifiers 2103 and 210
4 and the like are added by the collective control unit 106 '.

The I / O processor (101), to which this packet is sent, transfers the batched end report to the host processor corresponding to a unit of I / O request or a unit of I / O request as it is. To do.

When the input / output request is a READ request, the data must be written in a predetermined area of the main storage device (121), and the location is obtained from the main storage address (2113) sent and written.

As described above, when the input / output request is a READ request for reading data from the disk device, the input / output processor 101 adds the main storage address indicating the write position of the main storage device 121 to the channel program. And send it to the disk controller 131,
When the disk controller reads data from the disk device in response to the READ request, it transfers this main memory address (2114) to the input / output processor together with the input / output end result (2108-2112) including the read data, This allows the input / output processor to write the read data to the address in the main memory.

In this case, the input / output processor uses one R
Only the channel program indicating the EAD request to which the write address is added may be collectively transferred to the disk control device, or may be collectively transferred together with other I / O requests.

Further, the disk control device uses one REA.
Only the result obtained by adding the main storage address to the input / output end result including the data read in response to the D request may be collectively transferred to the input / output processor. You may transfer together with the other input / output completion result regarding an apparatus.

Further, the disk controller collectively manages the write addresses corresponding to the channel programs indicating a plurality of I / O requests including the READ request, which are transferred separately from the I / O processor and are related to the same disk device. Alternatively, the input / output end result including the data read in response to the READ request may be collectively transferred to the input / output processor together with other input / output end results corresponding to the plurality of input / output requests. good.

As described above, in this embodiment, the channel control processor sends the channel programs and write data relating to a plurality of input / output requests to the disk controller as a set of transfer data.
Since the execution timing of each command in each channel program is controlled, the transfer time of these channel programs and write data becomes shorter than before.

The following input / output commands 123, 124, 125 and data 126, 127 stored in the main storage device 121, which have been conventionally generated by the above control, are stored.
The overhead of incorporating 128 into the I / O processor can be reduced. (1) Judgment of presence / absence of input / output request (2) Extraction of input / output request (3) Invalidation of extracted input / output request (4) Extraction of main memory device address in which channel command is stored from input / output request (5 ) Retrieving one channel command from the main memory (6) Repeating (5) until one I / O request is completed (7) Returning to (1) to process the next I / O request. ), (2) are taken out at once,
The control transfer overhead from (1) to (2) and (7) to (1) can be reduced, and from (3) to (6), continuous channel command extraction and multiple I / O requests can be performed once. As described above, the control transfer overhead across a plurality of micro program modules can be reduced.

Further, it is possible to reduce the following overhead that occurs when a command or data is transferred from the input / output processor to the disk controller.

(A) Analyze the channel command fetched from the main storage device. (B) Determine whether it is a command for the disk controller or a command for the I / O processor. If the command is for the disk controller, the disk for which the command is specified Transfer to controller (c) Execute command if it is command to I / O processor (d) Repeat (a) to (c) until one I / O request is completed (a) to (d) are batch As a result, a plurality of I / O requests are processed to reduce the control transfer overhead across the micro program module.
The simplification of the process of (c) greatly improves the performance. As described above, the channel command words 123, 12 are sent from the I / O processor 101 to the disk controller 131.
When transferring 4,125, a command (for example, a TIC command) not directly related to the disk control device 131 is removed, and the command sequence is collectively included in the disk control device 1.
Transferred to 31. The meaning of the TIC command is as follows. Disk controller is SEEK, SEARC
Although a series of processes such as H and READ / WRITE are performed, these commands are transferred from the input / output processor to the disk controller one by one. However, the S
The EARCH command is a process for determining whether or not the disk head has arrived at a predetermined one, but when the I / O processor transfers this command to the disk controller, it starts executing the next channel command. As it is, it does not operate normally. In other words, if the next READ / WRITE command is executed at this point, READ / W will be performed for the current position of the disk head.
Since RITE is executed, illegal data is read and written. Therefore, TIC command SEARCH
Place it between the command and the READ / WRITE command,
It is necessary to continue executing the REARCH command until the disk head arrives at the position where the target data exists by the SEARCH command. However, by not performing such synchronous processing on the input / output processor 101 side as in the present embodiment, it becomes possible to asynchronously perform the processing which was conventionally performed synchronously. ) And (c) can be greatly reduced.

Compared to the type chart according to the processing procedure according to the prior art shown in FIG. 17A, according to this embodiment, as shown in FIG. 17B, in the data flow by the channel control of this embodiment, the I / O request queue is Since the queued I / O requests are collectively processed, as shown in the command / data transfer 1515 or 1516, there are some places where a plurality of command / data transfers are performed without causing channel overhead. The number of batches differs depending on the input / output load. At low load, it approaches the conventional channel operation, and at high load, the number of batches increases. Since such control is automatically performed, it is possible to perform command / data transfer with a response as short as possible without waiting for an unnecessarily large number of input / output requests. Further, since the intervention of overhead is suppressed to a necessary minimum by integrating the input / output requests, higher throughput can be achieved as compared with the conventional channel device. In particular, the faster the channel speed, the greater the effect of the present invention. This is because in this embodiment, an increase in the relative overhead ratio, which is caused by the fact that the overhead is hardly changed even if the data transfer time is shortened by increasing the channel speed, can be suppressed in the present embodiment. Further, it is envisioned that the cable length between the input / output processor forming the channel path and the disk controller etc. will be extended due to the expansion of the system in the future. As the channel path is extended in this way, the time until the connection is established between the two becomes longer, and the overhead at the time of data transfer becomes larger. Even in such a case, according to the present embodiment, it is possible to suppress an increase in the overhead ratio and perform efficient data transfer.

(Embodiment 2) Next, another embodiment will be described.

FIG. 18 is a diagram showing a flow of processing in the collective control unit 106 when the response priority control is performed in this embodiment. Collective control unit 1 as in the above embodiment
The process of 06 has two activation contracts. One is an activation request from the channel path selection / input / output request registration unit 104, and the other is an activation request from the data transfer processing unit 112. When an input request is issued from the input / output request registration unit 104 (step 1601), the collective control unit 106 uses the channel busy detection unit 105 to set the channel path control table 1
03, it is detected whether or not the channel path corresponding to the device identifier for which an input / output request has been made is available (step 1602). As a result, the desired channel path 140
If is "BUSY", the process is terminated. If not, the process proceeds to step 1604 (step 1603). In step 1604, the input / output request queue identifier corresponding to the channel path is acquired from the channel path control table 103. Next, the I / O request is extracted while adding the data length of the data to be transferred to the disk controller 131 from the I / O request queue 122 corresponding to the I / O request identifier acquired in step 1604. Then, when the data length exceeds a predetermined length, the fetching of the input / output request ends (steps 1605 and 1606). In addition, step 1
In 606, except when the data length exceeds a predetermined length,
Even if there is no I / O request to be taken out, the process proceeds to the next step. When the extraction of the I / O request is completed, the corresponding wait request number field 6 of the channel path control table 103
A value obtained by subtracting the extracted number of input / output requests from 03 is set in the requested number field 603, and the channel device status field 605 is set to "BUSY" (step 1607). After that, the plurality of extracted input / output requests are collectively sent to the input / output request analysis unit 111 (step 1608).

The activation request from the data transfer control unit 112, which is another activation trigger, is generated when the data transfer of any channel path is completed. At this time, the data transfer control unit 112 sends information indicating which channel path has completed the data transfer (step 1609). In step 1610, the channel path control table 103 is searched based on these pieces of information to see if there is a waiting input / output request to use this channel path. As a result, if there is no waiting input / output request, the process ends, and if not, the process moves to step 1602.

By performing such control in the collective control unit 106, it becomes possible to perform input / output control giving priority to the response to the host device or the like. If the number of batches is limited, the transfer time of data or commands will be shortened, and the throughput will be somewhat lowered, but this embodiment is effective when it is desired to give priority to the response to the host device or the like.

(Embodiment 3) Next, still another embodiment of the present invention will be described.

FIG. 19 is a diagram showing a flow of processing in the collective control unit 106 when the response priority control is performed in this embodiment. In this embodiment, the processing in step 1706 is different from that in step 1606 of the second embodiment. In this embodiment, a predetermined number of I / O requests are fetched from the I / O request queue corresponding to the I / O request identifier obtained in step 1704, and the fetching of the remaining I / O requests is completed. That is, it is judged whether or not the number of input / output requests fetched in step 1706 has reached a predetermined number (or whether or not there are no more input / output requests to be fetched), and the number of fetched I / O requests is equal to the predetermined number. Before the number of input / output requests is exceeded, the input / output requests are fetched in step 1705. When the number of fetched input / output requests exceeds a predetermined number, the process proceeds to the next step. Step 1602 in the second embodiment is replaced with step 1701 in the present embodiment.
By changing as described above, the process of fetching the I / O request can be speeded up. This is because when a plurality of channel command words are designated as a series of channel command word strings, in the second embodiment, each time an input / output request is taken out, the chain of channel command words must be repeated several steps to calculate the data length. This is because it is necessary to count the number of fetched I / O requests in the present embodiment, whereas this is not necessary. However, the present embodiment does not consider the data length, which is a major factor in the channel path usage time. Therefore, it is not suitable when the change in the I / O request length is large, and is effective in an environment where the change in the I / O request length is small. The other processes in this embodiment are performed in the same manner as in the other embodiment.

(Embodiment 4) In each of the above embodiments shown in FIGS. 1 and 2, control is performed using the control processors 136, 137 and 140, but the functions of these processors may be replaced by dedicated hardware. You can FIG. 24 is a block diagram showing an example in which all the configurations of FIGS. 1 and 2 are configured by hardware in such a manner. In the figure, a portion having the same function as the block of FIG.
The same parts are designated by the same reference numerals as those in FIG. 2, and the description thereof will be omitted.

[0098]

As described above, according to the present invention, it is possible to perform input / output in which the overhead required for starting and terminating a channel is suppressed to a necessary minimum and the response time is hardly reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an input / output subsystem to which a data input / output system and a data input / output control method in the system according to the present invention are applied.

FIG. 2 is a block diagram showing a configuration of each control processor s in FIG.

FIG. 3 is a flowchart showing processing in the input / output processor.

FIG. 4 is a diagram showing an example of an input / output request.

FIG. 5 is a diagram showing an example of a channel command word.

FIG. 6 is a diagram showing another example of channel command words.

FIG. 7 is a diagram showing an example of a connection configuration of a disk device.

FIG. 8 is a diagram showing an example of a channel path control table.

FIG. 9 is a diagram showing the structure of an input / output request queue.

FIG. 10 is a view for explaining the arrangement of input / output request queues.

FIG. 11 is a diagram showing a flow of processing in a channel path selection / input / output request registration unit.

FIG. 12 is a diagram showing a flow of processing in a collective control unit.

FIG. 13 is a diagram showing an example of a disk device control table.

FIG. 14 is a diagram showing a flow of disk command processing in a command processing unit.

FIG. 15 is a diagram showing an example of disk command processing.

FIG. 16 is a diagram showing how data is transferred.

FIG. 17 is a diagram showing a conventional channel control data flow and a channel control data flow according to the first embodiment of the present invention.

FIG. 18 is a diagram showing the flow of processing in the collective control unit when response priority control is performed in another embodiment.

FIG. 19 is a diagram showing the flow of processing in the collective control section when performing response priority control in yet another embodiment.

FIG. 20 is a diagram showing a channel program indicating a WRITE request and transfer to the disk controller.

FIG. 21 is a diagram showing transfer of an input / output end result in response to a WRITE request in the input / output processor.

FIG. 22 is a diagram showing a channel program indicating a READ request and transfer to the disk controller.

FIG. 23 is a diagram showing transfer of an input / output end result in response to a READ request in the input / output processor.

FIG. 24 is a block diagram showing the configuration of still another embodiment of the present invention.

FIG. 25 is a detailed flowchart of a startup process performed by a command processing unit.

Claims (34)

[Claims] 1. An I / O control device for controlling execution of a plurality of I / O requests to one of a plurality of external storage devices issued by a host device, and a command transferred from the I / O control device. In an input / output control system having an external storage controller for controlling the plurality of external storage devices, (a) a plurality of input / output requests issued from the host device from a storage device holding a plurality of control programs. A control program specified by at least one input / output request to be processed is read by the input / output control device, (b) the read control program is transferred from the input / output control device to the external storage control device, (c) temporarily storing the transferred control program in the external storage controller, and (d) executing the stored control program under the control of the external storage controller. Input and output control method with. 2. The executing step (d) is a step of sequentially executing a plurality of commands included in the stored control program at a timing depending on an operation of one external device to be controlled by the control program. The input / output control method according to claim 1, further comprising: 3. (e) When the read control program requests writing of data to the one external storage device, write data designated by the read control program is input from the storage device. The method further comprises a step of reading by the output control device, and the transferring step (c) includes a step of transferring the read control program and the read write data to the external storage control device. (F) stores the transferred write data, and (g) controls the stored write data by the stored control program at an appropriate timing during execution of the plurality of commands. The input / output control method according to claim 1, further comprising a step of transferring to a storage device. 4. The input / output control according to claim 3, wherein the transfer step (c) includes a step of transferring the read control program and the read write data together to the external storage controller. Method. 5. The executing step (d), when the stored control program designates reading of data from one of the plurality of external storage devices, the data designated by the control program is stored in the storage unit. From the one external storage device to be controlled by the stored control program, and the read data and the write address for the data of the storage device specified by the stored control program are input to the input / output control device. The input / output control method according to claim 1, further comprising a step of transferring. 6. An input / output control device for controlling execution of a plurality of input / output requests to one of a plurality of external storage devices issued by a host device, and a command transferred from the input / output control device. In an input / output control system having an external storage controller for controlling the plurality of external storage devices, (a) a plurality of input / output requests issued from the host device from a storage device holding a plurality of control programs Of the control program specified by at least one input / output request to be processed by the input / output control device, and (b) the read control program writes data to one of the plurality of external storage devices. Is specified, the write data is read from the storage device by the input / output control device, and (c) the read control program and write data are input / output. (D) a plurality of commands included in the stored control program and the stored write data to be processed by the external storage control device; An input / output control method comprising a step of transferring from a device to the external storage control device. 7. An input / output control device for controlling execution of a plurality of input / output requests for one of a plurality of external storage devices issued by a host device, and a command transferred from the input / output control device. In an input / output control system having an external storage controller for controlling the plurality of external storage devices, (a) among a plurality of input / output requests issued from the host device,
By selecting a plurality of I / O requests to be processed, (b) a plurality of control programs designated by the selected plurality of I / O requests from the storage device holding the plurality of control programs by the I / O control device Read, (c) transfer the read control programs from the input / output control device to the external storage control device, and (d) temporarily transfer the transfer control programs to the external storage control device. I / O control method comprising the step of: (e) executing the stored plurality of control programs under the control of the external storage controller. 8. The executing step (e) includes a step of executing, in parallel, a plurality of channel control programs requesting an input / output operation with respect to different external storage devices among the plurality of stored control programs. 7. The input / output control method described in 7. 9. The storage step (d) includes a step of storing the transferred plurality of control programs in a plurality of command storage areas in a distributed manner, and the execution step (e) includes different command storage areas. 9. The input / output control method according to claim 8, further comprising the step of executing a plurality of channel control programs stored in the area and requesting input / output operations for different external storage devices in parallel. 10. The transfer step (c) comprises, together with the read control programs, a plurality of identification information for identifying an external storage device to be controlled by one of the control programs. Is transferred to the external storage control device, and the execution step (e) determines an external storage device to be controlled by the transferred plurality of control programs from the transferred plurality of identification information. The input / output control method according to claim 7, further comprising steps. 11. The input / output control method according to claim 7, wherein said transfer step (c) includes a step of transferring the read control programs together to said external storage controller. 12. (f) When one or a plurality of the read control programs specify one or a plurality of write data for the plurality of external storage devices, the one or a plurality of write data. Further comprising the step of reading from the storage device by the input / output control device, the transfer step (c) including the plurality of read control programs and the read one or more write data. 8. The input / output control method according to claim 7, further comprising a step of transferring to the external storage control device. 13. The transfer step (c) includes a step of transferring the read plurality of control programs and the read one or more write data together to the external storage control device. Item 12. The input / output control method according to item 12. 14. The input / output control device is connected to the external storage control device via a plurality of channel paths, and the plurality of external storage devices can use an input / output request requesting an input / output operation for each of them. One or more channel paths are assigned, and the selecting step (a) includes
8. The input / output control method according to claim 7, further comprising the step of selecting a plurality of input / output requests requesting an input / output operation for one or a plurality of external storage devices to which the same channel path is assigned. 15. (f) Among a plurality of I / O request queues provided respectively corresponding to one of the plurality of channel paths, each of the plurality of I / O requests issued by the host device,
The selection step (a) further includes the step of storing in one input / output request queue provided corresponding to one channel path assigned to the external storage device designated by each input / output request. 15. The input / output control method according to claim 14, further comprising the step of selecting a plurality of input / output requests stored in one of the plurality of input / output request queues. 16. The selecting step (a) comprises, when a new I / O request is transferred from the host device, a channel allocated to an external storage device designated by the I / O request. The input / output control method according to claim 14, which is executed for the one channel path under the condition that the path is available. 17. The input / output according to claim 14, wherein the selecting step (a) is executed for one of the plurality of channel paths when any one of the plurality of channel paths changes from the used status to the unused status. Control method. 18. The selecting step (a) comprises a step of selecting a plurality of input / output requests under the condition that the total amount of write data required by the selected plurality of input / output requests does not exceed a predetermined amount. 13. The input / output control method according to claim 12, which has. 19. The input / output control method according to claim 12, wherein said selecting step (a) includes a step of selecting a predetermined number of input / output requests. 20. (f) When a response to be transferred from the plurality of external storage devices to the input / output control device is output as a result of executing any command in the stored plurality of control programs, The response is temporarily stored in a predetermined storage area in the external storage control device, and (g) when there are a plurality of responses stored in the storage area,
8. The input / output control method according to claim 7, further comprising the step of transferring the responses together to the input / output control device. 21. An input / output control device for controlling execution of a plurality of input / output requests to one of a plurality of external storage devices issued by a host device, and the command transferred from the input / output control device. An external storage control device for controlling a plurality of external storage devices, wherein the input / output control device comprises (a1) a storage device holding a plurality of control programs,
A means for reading out a control program specified by at least one input / output request to be processed among a plurality of input / output requests issued from the host device; and (a2) the read control program for the external storage control device. And an external storage control device comprising: (b1) a means for storing the transferred control program; and (b2) an input / output control system having a means for executing the stored control program. . 22. The executing means (b2) comprises means for sequentially executing a plurality of commands included in the stored control program at a timing depending on the operation of one external device to be controlled by the control program. Claim 21 having
Input / output control system described. 23. The input / output control device comprises: (a3) write data specified by the read control program when the read control program requests writing of data to the one external storage device. Further comprising means for reading out from the storage device, the transfer means (a2) having means for transferring the read control program and the read write data to the external storage control device, The external storage control device comprises (b3) means for storing the transferred write data, and (b4) transfer the stored write data to the one external storage device at an appropriate timing during execution of the control program. 22. The input / output control system according to claim 21, further comprising: 24. The input / output control according to claim 23, wherein the transfer means (a2) has means for transferring the read control program and the read write data together to the external storage controller. system. 25. The execution means (b2), when the stored control program specifies reading of data from one of the plurality of external storage devices, the execution unit (b2) sets the data specified by the control program to the one of the plurality of external storage devices. 22. A means for reading from the external storage device, and means for transferring the read data and the write address of the data in the storage device designated by the stored control program to the input / output control device together with the read data. I / O control system. 26. Based on an input / output control device for controlling execution of a plurality of input / output requests to one of a plurality of external storage devices issued by a host device, and a command transferred from the input / output control device. The input / output control device has an external storage control device for controlling the plurality of external storage devices, and the input / output control device includes: (B) means for reading a control program specified by at least one input / output request to be processed, and (b) when the read control program specifies write data for one of the plurality of external storage devices, Means for reading the write data from the storage device; (c) means for temporarily storing the read control program and write data; and (d) the stored control program. A plurality of commands and the stored write data contained in the arm in order to be processed by the external storage control unit, input-output control system having a means for transferring them to the external storage controller. 27. The I / O controller for controlling execution of a plurality of I / O requests to one of a plurality of external storage devices issued by a host device, and the command transferred from the I / O controller based on the I / O controller. An external storage control device for controlling a plurality of external storage devices, wherein the input / output control device comprises (a1) a storage device holding a plurality of control programs,
Means for reading a plurality of control programs specified by a plurality of input / output requests to be processed among a plurality of input / output requests issued from the host device; A storage controller, and the external storage controller has (b1) means for storing the transferred plurality of control programs, and (b2) executes the stored control programs. Input / output control system having means. 28. The storage means (b1) has a plurality of storage areas for storing the transferred plurality of control programs in a distributed manner, and the execution means (b2) has a plurality of storage areas. 28. The input / output control system according to claim 27, further comprising means for executing, in parallel, a plurality of channel control programs requesting an input / output operation for different external storage devices among the plurality of control programs stored in the. 29. When the one or more of the plurality of read control programs specify one or more write data to the plurality of external storage devices, the input / output control device further comprises: The transfer means (a2) further has a unit for reading one or a plurality of write data from the storage device, and the transfer unit (a2) stores the read control programs and the read one or a plurality of write data. 28. Means for transferring to the external storage controller
Input / output control system described. 30. The transfer means (a2) has means for transferring the read control programs and the read one or more write data together to the external storage control device. Item 29. The input / output control system according to item 29. 31. The input / output control device is connected to the external storage control device via a plurality of channel paths, and the plurality of external storage devices can use an input / output request requesting an input / output operation for each of them. One or a plurality of channel paths, the read means is provided corresponding to one of the plurality of channel paths, respectively, and a plurality of external storage devices using the corresponding channel paths are assigned. A plurality of read means for reading the control program specified by the input / output request from the storage device, which are operable in parallel with each other, and the transfer means are provided corresponding to one of the plurality of channel paths, respectively. A plurality of mutual transfer programs for transferring the plurality of control programs read by the reading means corresponding to the respective corresponding channel paths to the external storage control device. Output control system according to claim 27, further comprising operable transfer means in parallel. 32. The input / output control means detects (a3) means for detecting whether or not the plurality of channel paths are in use, and (a4) any one of the channel paths is not in use. 32. The input / output control system according to claim 31, further comprising means for activating one reading means provided corresponding to the channel path among the plurality of reading means. 33. When a new I / O request is transferred from the host device, the detecting means uses one channel path assigned to one external storage device designated by the I / O request. 33. The input / output control system according to claim 32, further comprising means for detecting whether or not it is inside. 34. An I / O controller for controlling execution of a plurality of I / O requests issued by a host device to one of a plurality of external storage devices, and the I / O controller via a plurality of channel paths. An external storage controller connected to the external storage controller for controlling the plurality of external storage devices based on a command transferred from the input / output controller, wherein the input / output controller is (a1) A plurality of channel control processors provided corresponding to one, and (a2) an input / output request control processor commonly provided to the plurality of channel control processors, wherein the input / output request control processor is b1) means for storing the input / output request issued from the higher-level device in a plurality of acquisition request queues, and (b2) a plurality of the plurality of input / output requests stored in the plurality of input / output request queues. Channel path A means for fetching a plurality of I / O requests that can be executed using one of the plurality of channel control processors, and the fetched I / O requests are provided corresponding to the one channel path among the plurality of channel control processors. And a means for notifying another channel control processor, each channel control processor, (c1) from the storage device holding a plurality of control programs,
Means for reading a plurality of control programs specified by a plurality of input / output requests notified from the input / output control processor; and (c2) means for transferring the plurality of read control programs to the external storage controller. The external storage controller has (d1) means for storing the transferred plurality of control programs, and (d2) input / output control having means for controlling execution of the stored control programs. system.