JPH0432421B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a channel control method for a data processing system.

[Prior art]

In such a data processing system, when a channel and an input/output device execute an input/output operation via an I/O interface, the channel is connected to one of a plurality of subordinate input/output devices,
Input/output operations can only be performed with connected input/output devices.

In order to become connected, the channel must make a second connection request to the input/output device, or the input/output device must make a first connection request to the channel. The problem is how to adjust by a method such as contention and shorten the time from the first or second join request to the join state (improve the performance of input/output operations).

Now, the startup operation of the input/output device is performed as follows. Input/output commands (hereinafter referred to as CHC) are controlled by the program.
Abbreviated as command. ) is executed, the central processing unit (hereinafter abbreviated as CPU) instructs the channel control unit (hereinafter abbreviated as CHC) to execute the CHC command, and upon receiving the instruction, the CHC executes the main memory. (hereinafter abbreviated as MEM) from the designated area,
Reads the device address word (hereinafter abbreviated as DAW) that specifies the type of operation of the CHC instruction, the channel location for executing the input/output operation, and the address of the input/output device. If there is, a command address word (hereinafter abbreviated as CAW) that specifies the memory address of a channel program consisting of a channel command word (hereinafter abbreviated as CCW) specifying details of input/output operations from a specified area of the MEM. ) is read. Thereafter, the status of the channel (or subchannel, if present) is checked, and if coupling with the input/output device is necessary, a second coupling request is sent from the channel to the input/output device.

Conventionally, in a channel with the same type of CHC, the CHC receives a signal (hereinafter referred to as
It is abbreviated as RQI signal. ) from the channel, and if possible, instructs the channel to accept the first connection request, and in response to this instruction, the channel starts accepting operations. accordingly
When CHC accepts a CHC command, if after instructing the corresponding channel to accept the first join request, when the channel cancels the acceptance operation of the first join request, the second Checks whether or not a join request instruction is necessary for a channel, and performs it if necessary, and similarly instructs a second join request if the corresponding channel is not instructed to accept the first join request. It checked whether it was necessary, performed it if necessary, and in response to the instruction, the channel started the operation of the second join request.

According to this method, the time from the second join request to the joined state does not increase, but the time from the first join request to the joined state increases from the channel to the joined state.
The RQI signal is sent to the CHC, and the CHC determines whether or not to accept the first connection request and instructs the channel, resulting in a significant increase in the number of requests, resulting in a decline in the performance of input/output operations.

[Purpose of the invention]

An object of the present invention is to shorten the time from the first connection request to a channel from an input/output device to the connection state. In cases where the channel has the function of accepting signals and selecting one of the multiple input/output devices under it, when a channel makes a second connection request to the input/output device, the CHC sends an “activation request” to the channel. ”
By issuing this instruction, conflict with the first connection request can be easily avoided, and the time from the second connection request to the connection state is not increased.

[Structure of the invention]

The present invention includes a channel control device that controls a plurality of channels, and a plurality of input/output devices connected to the channels and controlled by the channels, wherein the channels are connected to a first input/output device from the input/output devices to the channels. In a data processing system including a control unit capable of receiving a connection request independently of the channel control device and selecting one from a plurality of input/output devices under control, before making a second connection request from the channel to the input/output device. means for instructing the channel to "start request" from the channel control device, and if the channel is in the operation of accepting the first connection request upon receiving the instruction, the channel is in the operation; to the channel controller;
The point in time when the operation is canceled is reported to the channel control device by an interrupt, and the first connection request is not accepted after the operation is canceled, and on the other hand, if the first connection request is not being accepted, the operation is performed. and means for reporting to the channel control device that the first connection request is not in progress, and not accepting the first connection request after the notification.

[Explanation of Examples]

Next, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of a data processing system implementing the present invention. 10 is
MEM, 11 is a main memory control unit (hereinafter abbreviated as MCU), 12 is a CPU, 13 is a CHC, 14 is a channel, 15 is an I/O interface, and 16 is an input/output device. 13 controls a plurality of channels 14, and the channels 14 control a plurality of input/output devices 16 connected through an interface 15.
It can be connected to one input/output device 16 on the interface 15, and performs input/output operations with one input/output device 16 at one point in time.

FIG. 2 shows a block diagram of one embodiment of a CHC and channel implementing the present invention. The CHC 13 includes a memory access section 20, a channel control section 21, and a channel data section 22. The memory access section 20 is connected to the MCU 11 through an interface 26, and is connected to the channel control section 21 and the channel data section 22.
Processes memory access requests etc. The channel control unit 21 is controlled by firmware,
Deciphers CHC instructions, channel programs, channels, status of input/output devices, etc., and decodes other parts within CHC.
Control channels. The channel data section 22 performs channel and
Controls data transfer with MEM. 23 is a channel connection section that connects the channel control section 21, channel data section 22, and channels. 24 is a channel and is equivalent to 14. interface 25
is an I/O interface and is equivalent to interface 15, and interface 26 is an MCU
-CHC interface.

FIG. 3 shows an example of a block diagram of the channel control section 21. 30 is a control storage address control section. Control memory (hereinafter abbreviated as CS). The address is determined by the firmware designation, that is, the signal 36, and the request from the CPU 12 (via the MCU 11), the channel data section 22, and the channel 24, that is, the signal 34. In this embodiment, the firmware uses the signal 34.
The starting address is given by
Processing will be performed at the address specified by . 31 is a control storage unit (hereinafter abbreviated as CS unit) in which firmware is stored;
is addressed by. The register 33 is a CS read register, in which read data from the CS section 31 is set and instructions from the firmware are given to other blocks. 32 is a data processing section, and a register 33
Receiving the signal 37 from the memory access section 20 and signals 38 and 39, the channel data section 22 and signals 310 and 311, and the channel connection section 2
3 and sending and receiving data via signals 312 and 313,
Sends instructions, etc.

FIG. 4 shows a flowchart when the firmware in the CS unit 31 is activated in response to an instruction to execute a CHC command from the CPU 12. When firmware is started, DAW and CAW from MEM10
, and checks whether the operation specified in the DAW requires connection with the input/output device and a second connection, and if connection is necessary, issues a "start request instruction" to the channel specified in the DAW. After that, a value in the channel 14 indicating whether the channel is being processed by the first connection request from the input/output device is displayed.
Read and check STAV F/F. STAV
If F/F is "1", there is a "boot start interrupt" requested from the corresponding channel when processing by the first connection request is canceled (if there is another request for firmware, it can be processed). be.),
If STAV F/F is "0", the second connection is made and the processing of the operation specified by DMW and CAW continues. Further, when a "startup start interrupt" is received from a channel, the same processing as when STAV F/F is "0" is performed.

FIG. 5 shows the operation flow when the channel 24 receives an "activation request instruction" from the firmware. When the instruction is received, it checks whether processing is in progress due to the first connection request from the input/output device, and
If the processing is in progress, set STAV F/F and wait for the processing to be released, and when the processing is released.
At the same time as resetting the STAV F/F, a “startup start interrupt” request is made to the channel control unit 21,
From now on, reception of the first join request will be prohibited. Furthermore, if the process is not currently being processed by the first connection request, it only prohibits reception of the first connection request from now on. In either case, subsequent operations are based on instructions later issued from the firmware.

〔Effect of the invention〕

As explained above, the present invention instructs the channel to "request activation" from the channel control device, and the channel performs the processing specified by the instruction, thereby allowing the channel to operate without deteriorating the performance of input/output operations. This has the effect of easily avoiding conflicts between the first and second connection requests between the input and output devices.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a data processing system implementing the present invention, FIG. 2 is a block diagram of an example of a channel control device and channel implementing the present invention, and FIG.
The figure is a block diagram of an example of a channel control device.
The figure shows the processing flow of the firmware of the channel control device that receives an instruction to execute an input/output command from the central processing unit, and FIG. 5 shows the processing flow of the channel that receives the "activation request" instruction from the firmware of the channel control device. 10... Main memory device (MEM), 11... Main memory control unit (MCU), 12... Central processing unit (CPU),
13... Channel control device (CHC), 14... Channel, 15... I/O interface, 16... Input/output device, 20... Memory access section, 21... Channel control section, 22... Channel data section, 23... Channel connection section , 24... Channel, 30... Control storage address control section, 31... Control storage (CS), 32... Data processing section, 33... CS read register, 34, 36
...CS address designation signal, 35...CS address signal, 37...Data processing unit control signal, 38, 39
...Memory access unit interface signal, 31
0, 311...Channel data part interface signal, 312, 313...Channel connection part interface signal.

Claims (1)

[Scope of Claims] 1. A channel control device that controls a plurality of channels, and a plurality of input/output devices connected to the channels and controlled by the channels, wherein the channels are connected to the channels from the input/output devices to the input/output devices. In a data processing system including a control unit capable of accepting a first connection request for a channel independently of the channel control device and selecting one from a plurality of input/output devices under control, a second connection request from the channel to the input/output device is provided. means for instructing the channel to "start request" from the channel control device before making a connection request; and upon receiving the instruction, if the channel is in the process of accepting a first connection request, the channel performs the operation; report to the channel control device that the operation is in progress, report the point at which the operation is canceled to the channel control device by interrupt, and do not accept the first connection request after the operation is canceled; A data processing system characterized in that the data processing system includes means for reporting to the channel control device that the first connection request reception operation is not in progress, and not accepting the first connection request after the report. Channel control method.