JP2000330921A - Channel controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize a channel controller which issues a command for canceling a process by a central processor side to cancel the process irrelevantly to whether or not the process of a command that the central processor sends to a channel device is started. SOLUTION: A CPU when making a semiconductor device file device 102 as a channel device control the writing, etc., of data makes the channel controller 101 perform the control instead. When a command for cancellation is issued after a command for that is issued, the channel controller 101 writes it to a 1st interruption flag register 111 by DMA(direct memory access) control not through an FIFO memory 28 differently from ordinary commands and sends it to a 2nd interruption flag register 112 to set a flag ON. Consequently, a SCSI(small computer system interface) bus is disconnected and the process is canceled. Then the channel controller informs the CPU 12 that the process is canceled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a channel control device, and more particularly to a channel control device capable of controlling a channel device such as a semiconductor file device by reducing a load on a central processing unit.

[0002]

2. Description of the Related Art With the improvement of functions of computers such as personal computers and the sophistication of peripheral devices, C computers have been developed.
The burden on PUs (Central Processing Units) is increasing. In such a situation, in order to reduce the burden on the central processing unit as much as possible, various devices such as file devices and printers are positioned as channel devices, and these channel devices are controlled by a channel control device different from the CPU. Generally adopted.

FIG. 6 shows an example of a computer system using a semiconductor file device as a channel device. The computer system includes a main control unit 11,
It comprises a channel control device 12 and a semiconductor file device 13.

[0004] The main controller 11 comprises a CPU 21 and a main memory 23 connected to the CPU 21 via a bus 22. The channel control device 12 includes a first DMA (dire) connected to the main control unit 11 by buses 24 and 25.
ct memory access) control unit 27 and FIFO (first-in first-out memory) memory 28, and first DMA control unit 27
To the first MPU (micropro
processor unit) 31, a first RAM (random access memory) 32 and a second DMA control unit 33,
Buses 35 and 36 connected to the other end of the IFO memory 28
A first SCSI (small computer system interface) controller 37 having one end connected together with a second DMA controller 33. The buses 38 and 39 connected to the other end of the first SCSI control unit 37 are connected to the buses 42 and 43 via the second SCSI control unit 41 of the semiconductor file device 13. These buses 42, 4
3 is connected to a third DMA control unit 45 and a semiconductor memory 46. Further, the third DMA control unit 45
7, and is connected to a second MPU 48 and a second RAM 49.

[0005] SCSI is a standard for connecting small computers such as personal computers and workstations to peripheral devices such as hard disks and optical disk devices. In personal computers, there is a tendency to use SCSI-based interfaces for input / output devices such as external hard disks, CD-ROM drives, and MO (magneto-optical disks) drives. For workstations and server machines, all are often unified with SCSI interfaces from the beginning.

It is assumed that the main controller 11 writes data to the semiconductor file device 13 in the conventional computer system shown in FIG. The main controller 11 issues an instruction to the channel controller 12 instead of directly issuing an instruction to the semiconductor file device 13. The first SCSI control unit 3 is provided between the channel control device 12 and the semiconductor file device 13.
7 and the second SCSI controller 41 are SCSI-connected. Instructions from the CPU 21 of the main control unit 11 are sequentially stored in the FIFO memory 28, read out in that order, and given from the channel control device 12 to the semiconductor file device 13.

[0007] Thereafter, the channel control device 12 controls the data writing to the semiconductor file device 13 and notifies the main control section 11 that the writing has been completed when the writing is completed. That is, the main control unit 11 is released from the subsequent processing when the instruction is given to the channel control device 12, and thereafter, it is only necessary to receive a notification that the data writing has been completed. That is, the main control unit 1
The CPU in 1 can concentrate on other processing until a next response is received from the channel control device 12.

The semiconductor file device 13 is used as an external storage device which can be accessed at a higher speed than a magnetic disk device or an optical disk device, and is therefore used more frequently than other external storage devices such as a magnetic disk device. Tend. By using the channel controller 12, the CPU
Since command processing such as data writing can be performed autonomously without the intervention of the FPC 21, such processing has been generalized as described above.

By the way, the memory capacity of the semiconductor file device 13 has been increased due to the recent improvement of memory
Due to the adoption of a technique for giving a plurality of commands to the channel control device 12 at once for high-speed processing, the channel control device 12 tends to receive more commands per unit time. The channel control device 12 includes:
Commands to other channel devices such as printers have also arrived, which is one of the causes of concentration of commands. For this reason, the time from when the CPU 21 issues a command to the channel control device 12 to when the processing result of the command is returned from the channel control device 12 is relatively long.

[0010] In such a situation, there may be a case where it is necessary to cancel the command issued by the CPU 21 before the processing of the command is completed and before the result is reported. An example is a case where writing or reading of other data is required due to a change in a situation that occurs while the time is delayed. When the channel control device 12 is used, the CPU 21 can simplify the processing, but only waits for a response from the channel control device 12. In other words, an unnecessary process cannot be canceled until the process is completed. There is also a problem that the probability of the operation is increased.

FIG. 7 is for explaining the first proposal proposed to solve this kind of problem. In this first proposal, the CPU 51 transmits the disk subsystem 53 and the tape subsystem 5 via the same bus 52.
4. It is connected to a plurality of devices such as another processing device 55. The disk subsystem 53 is a magnetic disk device 5
The tape subsystem 54 is provided for input / output control of the magnetic tape device 57.

In the first proposal, subsystems such as a disk subsystem 53 and a tape subsystem 54 are dispersedly arranged in order to eliminate the busyness of command processing by one channel controller. And
The problem of collision between commands due to the concentrated use of the bus 52 that occurs here is solved both by bus arbitration (arbitration) and by providing an interruption time between processing by each command. In other words, when low-priority data transfer is performed, the bus 52 is released by providing a time for temporarily suspending the use of the bus 52, and the opportunity of using the bus 52 is changed to another device after the suspension time elapses. Also give. As a result, when a conflict occurs in use of the bus 52, the occupation of the bus 52 is determined by arbitration. This enables the distributed use of the bus 52.

This proposal is disclosed in Japanese Patent Application Laid-Open No. 60-74071, but is disclosed in Japanese Patent Application Laid-Open No. 6-25917.
A similar proposal is also made in Japanese Patent Publication No. These proposals are effective as a response when commands or processes are concentrated. However, considering a case in which one process is completed with a command and then a command for canceling the command is output as described above, the cancellation command is also delayed due to arbitration or interruption, which is an effective solution. Not a solution.

FIG. 8 shows a second proposal made conventionally. The system to which this proposal is applied is composed of a host device 61 and a plurality of workstations 63 ₁ , 63 ₂ ,... Connected to the host device 61 by a transmission line 62. A plurality of input / output devices 68 such as a display 64, a printer 65, a magnetic disk device 66, and a floppy disk device 67 are connected to the first workstation 63 _1, which is typically illustrated. The host device 61 includes an input / output device control unit 71 connected to a transmission line 62 and a memory 72 connected thereto. The first workstation 63 ₁ includes a control unit 74 connected to the transmission line 62 and a register 75 connected to the control unit 74.

In this proposal, the register 75 is connected to the input / output device 68
Input / output devices (display 64, printer 65, magnetic disk device 66,
It is provided for setting the machine number of the floppy disk device 67, etc., input / output commands, etc., and performing input / output processing. That is, the host device 61 performs the input / output processing by setting each device number and the start command of the input / output device 68 via the transmission line 62.

When an interruption factor occurs, the host device 61 transmits, for example, to the first workstation 6 via the transmission line 62.
31. Interruption for interrupting the input / output devices 68 of all device numbers without searching the register 75 of ₁ for which device number of the input / output devices 68 issued the command. The command is set in the register 75. Based on this, the first workstation 63 ₁ notifies the input / output devices 68 of all the machine numbers, such as the display 64, the printer 65, the magnetic disk device 66, and the floppy disk device 67, of the interruption command. The display 64, the printer 65, and the magnetic disk device 6 receiving the suspend instruction
6. Each device such as the floppy disk device 67 interrupts the input / output command if it is being processed, and sends an end notification to the first device.
Return of the workstation 63 _1, does not return a completion notice if in the process of input and output commands. The first workstation 63 ₁ stores the machine number that has received the notification of the end of the interruption,
The host device 61 is notified that the processing has been interrupted. The host device 61 performs an end determination and an end process.

That is, in the second proposal, an interrupt command for interrupting the input / output devices 68 of all the machine numbers is set in the register 75, and when the interruption of the processing device is confirmed, the interrupt command is set. The host device 61 is notified.

[0018]

[Problems that the Invention is to Solve According to the second proposal, the interruption instruction to a first one of the channel control unit such as a workstation 63 ₁ arrives, the interruption instruction is connected to the channel control unit Even if some of the input / output devices 68 are originally targeted, all of the input / output devices being processed are subjected to the interruption processing. Therefore,
There is a problem that the processing is interrupted even for an input signal device that should not be interrupted.

In this proposal, the display 64, printer 65, magnetic disk device 66,
Among the devices such as the floppy disk device 67, the one that is actually performing the processing is a target of the interruption of the processing. Therefore, if the process to be canceled has not been performed yet because another process is delayed or the like, the end notification is not transmitted to the host device. Therefore, one channel control device such as the first workstation 63 ₁ not only needs to perform the action of interrupting the processing many times after a while, but also performs the interrupting processing until the target processing starts. You can't do that. Therefore, there is a case where the time until the interruption is prolonged in some cases, and there is a possibility that an inconvenience such as the progress of the failure occurs during the time.

Therefore, an object of the present invention is to allow a central processing unit to issue a command to cancel processing and cancel the processing regardless of whether or not processing of a command issued by the central processing unit to a channel device is started. It is to provide a channel control device capable of performing the following.

[0021]

According to the first aspect of the present invention, (a) a process for causing a channel command transmitted from a central processing unit for control of a channel device to cause the channel device to perform a predetermined process. A channel command type determining means for determining whether the command is a command or a cancel command for canceling the processing; and (b) a channel for temporarily storing the channel command determined by the channel command type determining means to be a processing command until processing is started. Command buffer means, and (c) channel device control means arranged on the output side of the channel command buffer means for executing processing by a channel command on the channel device;
(D) cancellation command supply means for providing the channel command determined by the channel command type determination means as a cancellation command to the channel device control means without passing through the channel command buffer means, and (e) supply by the cancellation command supply means. When the corresponding process is canceled by the canceled command, the channel control device is provided with a completion notifying means for notifying the central processing device of the cancellation.

That is, according to the first aspect of the present invention, the channel command type discriminating means includes a processing command for causing the channel device to perform a predetermined process with respect to the channel command transmitted from the central processing unit for controlling the channel device. It is determined whether the command is a cancel command for canceling the process. If the command is a process command, the command is stored in a channel command buffer unit for temporarily suspending the process. If it is a cancel command, the channel command is given to the channel device control means without passing through the channel command buffer means, so that the processing can be canceled even if the processing command is in the middle of or before the processing. When the corresponding processing is canceled, this is notified to the central processing unit.

According to the second aspect of the present invention, (a) the channel command sent from the central processing unit for controlling the channel device is a process command for causing the channel device to perform a predetermined process or the process is canceled. Channel command type determining means for determining whether the command is a cancel command for
(B) First-in, first-out memory means for sequentially storing the channel commands determined by the channel command type determination means as processing commands until the start of processing; Channel device control means for executing processing by a command; and (d) cancellation command supply means for providing the channel command determined by the channel command type determination means to be a cancellation command to the channel device control means without passing through the first-in first-out memory means. (E) The channel control device is provided with completion notification means for notifying the central processing unit when the corresponding processing is canceled by the cancellation command supplied by the cancellation command supply means.

That is, according to the second aspect of the present invention, the channel command type discriminating means is a processing command for causing the channel device to perform a predetermined process with respect to the channel command sent from the central processing unit for controlling the channel device. It is determined whether the command is a cancel command for canceling the process. If the received command is a processing command, the command is stored in a first-in first-out memory means for waiting the processing in order. In the case of a cancel command, the channel command is given to the channel device control means without passing through the channel command buffer means, so that the processing command is in the middle of processing or is still in the first-in first-out memory means and is in the state before processing Processing can be canceled. When the corresponding processing is canceled, this is notified to the central processing unit.

According to the third aspect of the present invention, (a) the channel command sent from the central processing unit for controlling the channel device cancels the process command for causing the channel device to perform a predetermined process. Channel command type determining means for determining whether the command is a cancel command for
(B) First-in, first-out memory means for sequentially storing the channel commands determined by the channel command type determination means as processing commands until the start of processing; A channel device control means for executing processing by a command, (d) a cancellation command storage means for storing a channel command determined to be a cancellation command by the channel command type determination means, and (e) a cancellation command for the channel command type determination means. A direct memory access control means for writing the channel command determined to be "1" to the cancellation command storage means by direct memory access, and reading out the written cancellation command and providing it to the channel device control means; When the processing corresponding the cancel command supplied by stages is canceled thereby and a completion notifying unit that notifies the central processing unit to the channel control unit.

That is, according to the third aspect of the present invention, the channel command type discriminating means includes a processing command for causing the channel device to perform a predetermined process on the channel command sent to control the channel device from the central processing unit. It is determined whether the command is a cancel command for canceling the process. If the received command is a processing command, the command is stored in a first-in first-out memory means for waiting the processing in order. If the command is a cancellation command, the command is stored in the cancellation command storage means by the direct memory access control means, and
The data is read out by the direct memory access control means and given to the channel device control means so that the processing by the cancel command is realized in a faster path. When the corresponding processing is canceled, this is notified to the central processing unit.

According to the fourth aspect of the present invention, (a) a channel command sent from the central processing unit for controlling the channel device is a process command for causing the channel device to perform a predetermined process or the process is canceled. Channel command type determining means for determining whether the command is a cancel command for
(B) First-in, first-out memory means for sequentially storing the channel commands determined by the channel command type determination means as processing commands until the start of processing; (E) channel device control means for executing processing by a command, and (d) flag on / off means for turning on a flag when the channel command type determining means determines that the command is a cancel command and turning off the flag otherwise. An interface disconnecting unit for disconnecting a communication interface with a corresponding channel device when the flag on / off unit turns on a flag;
(V) When the interface disconnecting means disconnects the communication interface, the channel control apparatus is provided with a completion notifying means for notifying the central processing unit that the corresponding cancel command has been executed.

That is, in the invention according to claim 4, the channel command type discriminating means is a processing command for causing the channel device to perform a predetermined process on the channel command sent to control the channel device from the central processing unit. It is determined whether the command is a cancel command for canceling the process. If the received command is a processing command, the command is stored in a first-in first-out memory means for waiting the processing in order. The flag is turned on when the channel command type discriminating means determines that the command is a cancel command by the flag on / off means, and otherwise the flag is turned off. When the flag on / off means turns on the flag, the corresponding channel is turned off. The communication interface with the device is disconnected, and when the communication interface is disconnected, the central processing unit is notified that the corresponding cancel command has been executed. That is, the processing by the processing command is canceled by cutting off the communication interface between the channel device and the channel control device by the cancellation command.

According to a fifth aspect of the present invention, in the channel control device of the fourth aspect, the communication interface is a SCSI interface.
An interface for communicating with the channel device through the bus, wherein the interface disconnecting means notifies the channel device via the SCSI bus that the corresponding processing command should be canceled and releases the SCSI bus from the channel device. And That is, SC
The adoption of an interface that communicates with the channel device via the SI bus realizes commonization of devices and high-speed processing up to cancellation.

According to a sixth aspect of the present invention, in the channel control device of the first to fifth aspects, the channel device is a semiconductor file device. It goes without saying that a device other than the semiconductor file device may be a target of the channel device. However, since the semiconductor file device is a typical channel device suitable for the present invention, this is exemplified.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

FIG. 1 shows an outline of a computer system using a channel control device according to an embodiment of the present invention. In FIG. 1, the same portions as those in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. The computer system according to the present embodiment includes a main control unit 11, a channel control device 101, and a semiconductor file device 102.

The configuration of the main control unit 11 is the same as the conventional one.
The channel control device 101 newly adds a first
Is added to the interrupt flag register 111 of FIG. Of course, the first suspend flag register 111 stores the first RA
It is also possible to configure as a part of M32. A second suspend flag register 112 is newly added to the bus 47 of the semiconductor file device 102. of course,
The second suspend flag register 112 is also used in the second RAM 4
9 can also be configured. Also, the first
The control programs stored in the second RAMs 32 and 49 or in a storage medium (not shown) are slightly different from those shown in FIG. 6 as described later.

FIG. 2 shows an outline of a processing flow in a computer system using the channel control device having such a configuration. Here, a case will be described in which the semiconductor file device 102 is taken as an example of the channel device, and the interruption processing is performed after an instruction to write data to the semiconductor file device 102 is issued.

First, the CPU 21 in the main controller 11 outputs a semiconductor file write instruction as a channel command to the channel controller 101 at time t ₁ (step S 121). Upon receiving this instruction, the channel control device 101 stores this instruction in the FIFO memory 28, and
By sequentially processing the other channel commands already stored in the FO memory 28, the semiconductor file device 102
A process for writing data to is started (step S122). Here, it does not matter whether the data write instruction is actually sent to the semiconductor file device 102.

Time t ₂ before notification of completion of data write processing from semiconductor file device 102
Then, it is assumed that the CPU 21 outputs an instruction to suspend writing of the semiconductor file by a channel command (step S12).
3). When the interruption instruction arrives at the channel control device 101, the bus 2 arranged in front of the FIFO memory 28
The first DMA control unit 27 connected to the first and second DMA control units 4 and 25 determines that the instruction is the interruption instruction, and the first interruption flag register 11
1 is turned on (ON) (step S12).
4). A bus 3 arranged behind the FIFO memory 28
5 and 36, the second DMA control unit 33
When the interruption flag of the interruption flag register 111 is turned on, this interruption instruction is issued by the interruption processing to the first SCS.
It is transmitted to the semiconductor file device 102 via the I control unit 37 and the second SCSI control unit 41 (step S
125).

When the semiconductor file device 102 receives the interruption instruction, the third DMA control unit 45 connected to the buses 42 and 43 disposed in front of the semiconductor memory 46 discriminates the instruction and outputs a second interruption flag. The interruption flag of the register 112 is turned on (step S126). As a result, the second MPU 48 issues a command interruption instruction to the second SCSI control unit 41 (step S127). Second S
When the CSI control unit 41 completes the command interruption based on this and notifies the second MPU 48, the third DMA control unit 45 is forcibly interrupted in this state where the interruption flag is on (step S128). , A SCSI bus release instruction (DISCONNECT) is issued, and the SC connected between the first and second SCSI control units 37 and 41 is issued.
The SI bus is released (step S129).

In this manner, the semiconductor file device 102
When the SCSI bus between the controller and the channel controller 101 is released, a "DISCONNECTED" interrupt as a SCSI command is input to the channel controller 101 (step S130). As a result, the control operations of the first and second DMA control units 27 and 33 are forcibly interrupted (step S131), and accordingly, the interrupt flag of the second interrupt flag register 112 is turned off (OFF). To complete the SCSI command (step S
132). As a result, the channel control device 101 performs the channel command completion processing (step S13).
3), an interruption completion notification (channel status) is sent to the CPU 21 (step S13).
4).

That is, in this embodiment, even if there is an unprocessed command in the FIFO memory 28 in the channel control device 12, the CPU 21 issues a first instruction to bypass the FIFO memory 28 so as to bypass the FIFO memory 28. The data is transmitted to the semiconductor file device 102 via a path such as the flag register 111 and the second interruption flag register 112. For this reason, the interruption processing is performed quickly.

FIG. 3 is a graph showing C in performing the above control.
7 specifically shows a state of control on the PU side. The CPU 21 in the main control unit 11 determines whether a channel command issue factor has occurred (step S201), an interrupt factor has occurred before the process is completed after the channel command is issued (step S202), or the channel control device It monitors whether the channel status has arrived from 101 (step S203). And
In a situation where these conditions are not met (step S2
01 to S203: N), other processes are executed in a time-sharing manner (step S204).

When a channel command issuance factor occurs (step S201: Y), a channel command is issued at a given time-division processing time (step S201).
205). On the other hand, if the interruption factor occurs before the channel status indicating that the processing has been completed after the channel command is issued (step S202: Y), an instruction for interrupting the execution of the channel command is issued. (Step S206). This instruction is also a kind of channel command. When the channel status has arrived from the channel control device 101 (step S203:
Y), the receiving process is performed by itself (step S)
207). The processing on the CPU 21 described above is not particularly different from the conventional processing.

FIG. 4 shows the flow of processing when a channel command on the channel controller side is received. The channel control device 12 waits for a channel command from the CPU 21 (step S22).
1). When the channel command is received (Y), it is determined whether or not the command is a command for instructing reading and writing to the semiconductor file device 13 (step S22).
2). If the command is a command for instructing reading and writing to the semiconductor file device 13 (Y), the first SCSI control unit 37 and the DMA control units 27 and 33 are set (step S223). Then, the data for writing or reading is transferred (step S224), and this does not cause an abnormality in the middle (step S22).
5: N), when the processing is completed normally (step S226:
Y), the first SCSI controller 37 and the DMA controller 2
A termination process is performed for steps 7 and 33 (step S22).
7).

On the other hand, if an abnormality occurs before the data transfer ends (step S225: Y), it is determined whether or not the interruption flag of the first interruption flag register 111 is on. (Step S22
8). The interrupt flag is ON when the CPU
21 has issued the interruption instruction. Therefore, in this case, it is no longer necessary to transfer data, so that the first SCSI control unit 37 and the DMA control units 27 and 33 are forcibly terminated (Step S).
229). If an abnormality has occurred in the data transfer even though the suspension flag is not turned on (step S228:
N), a failure has occurred. Therefore, in this case, the channel control device 12 notifies the CPU 22 that a failure has occurred (step S230).

If the channel command received from the CPU 22 in step S222 is not a command for instructing reading / writing to the semiconductor file device 13 (N), it is an interruption instruction to the channel control device 12. Therefore, in this case, the first interruption flag register 111 is turned on (step S23).
1). Then, an interruption instruction for interrupting the data transfer to the semiconductor file device 13 is issued (step S232).

FIG. 5 shows the flow of processing on the semiconductor file device side. Since the semiconductor file device 13 is connected to the channel controller 101 via a SCSI interface, the channel controller 101
It monitors the arrival of a command (step S24).
1). When a SCSI command is received (Y), the second M
The PU 48 checks whether or not this is an instruction to read / write the semiconductor file (step S242). If the instruction is not an instruction to read / write the semiconductor file (N), the instruction is to interrupt the reading / writing. Therefore, in this case, the second
The interruption flag of the interruption flag register 112 is turned on (step S243). In this case (Y), reading and writing of the semiconductor file must be interrupted. Therefore, the second SCSI controller 41 and the third DMA controller 4
5 is forcibly terminated (step S244), and “DISCONNECTED” is sent to the channel controller 101.
An interrupt is notified (step S24).
5).

On the other hand, when the SCSI command is an instruction to read / write a semiconductor file (step S
242: Y), it is checked whether or not the interruption flag of the interruption flag register 112 is turned on (step S246). If the suspension flag is on, it means that there is an instruction to suspend the read / write operation. In this case (Y), the second SCSI control unit 41
Then, the third DMA control unit 45 is forcibly terminated (step S244), and a notification process of a "DISCONNECTED" interrupt is performed to the channel control device 101 (step S245).

On the other hand, in the normal case where the interruption flag is not turned on (step S246: N), the setting of the second SCSI control unit 41 is performed so that data is written to or read from the semiconductor memory 46. Is performed (step S247). Thereafter, it is checked again whether the interruption flag is on (step S248). This is to prevent the process from proceeding to unnecessary processing after the interruption flag is turned on later. Therefore, when the interruption flag is on (step S248: Y), the process proceeds to step S244, where the process for data transfer is forcibly terminated and “DIS
Notification processing of a "CONNECTED" interrupt is performed (step S245).

If the interruption flag is not turned on in step S248, there is no instruction for interruption, so the third
Is set in the DMA control unit 45 (step S2).
49). Then, data for writing or reading is transferred (step S250), and this does not cause an abnormality in the middle (step S251: N).
When the processing is completed normally (step S252: Y), the second S
The termination process is performed for the CSI control unit 41 and the third DMA control unit 45, and the normal end of the SCSI command is notified to the channel control device 101 (step S253).

On the other hand, if an abnormality occurs before the data transfer ends (step S251: Y), it is determined whether or not the interruption flag of the second interruption flag register 112 is on. (Step S25
4). If the interruption flag is ON, it is no longer necessary to transfer data (Y), so step S
The processing after 244 is performed. If an abnormality occurs while the suspension flag is off (step S2
54: N), a failure has occurred. Therefore,
In this case, the semiconductor file device 102 notifies the channel control device 101 that a failure has occurred (step S255).

When the interruption flag is turned on in step S243, the second SCSI controller 41 and the third DMA controller 45 are forcibly terminated in step S244 (step S244). However,
At this point, the second SCSI controller 41 and the third DM
There is a case where the A control unit 45 is in a state before being set for data transfer. In such a case, step S24
4 without performing the processing of “DISC”
Notification of "ONNECTED" interrupt (step S
245) alone.

In this embodiment, when the SCSI bus is released, "DISCONNECT" is sent to the channel controller 101 side.
Since the "ED" interrupt was entered, the conventional "DISC"
In addition, a failure process can be started in the same situation as the conventional case where the interruption flag described in the present embodiment is not set.

In the embodiment described above, the channel control device 101 is used as the semiconductor file device 10 as a channel device.
2 has been described, the channel device need not be the semiconductor file device 102 but may be another external storage medium such as a magnetic disk device or a non-storage medium such as a printer. is there.

Also, the number of channel devices controlled by the channel control device need not be only one as in the embodiment, but may be plural. In this case, each channel device is independently controlled by turning on / off the corresponding suspend flag.

Further, in the embodiment, the example in which the SCSI interface is used has been described. However, it is needless to say that the present invention can be applied to a channel device connected using another interface.

[0056]

As described above, claims 1 to 4 are described.
According to the invention described in claim 1, according to the invention described in claim 1, the channel command type determination means performs a predetermined process on the channel command sent from the central processing unit for controlling the channel device. Since it is determined whether the processing command is a processing command for canceling the processing or a cancellation command for canceling the processing, it is possible to easily take a measure for quickly performing the processing for the cancellation command with priority.

According to the third aspect of the present invention, the cancellation command is stored in the cancellation command storage means by the direct memory access control means, and is read out by the direct memory access control means and given to the channel device control means. Processing speeds up.

Further, according to the present invention, there is provided flag on / off means for turning on a flag when the channel command type discriminating means determines that the command is a cancel command, and for turning off the flag otherwise, and providing the flag on / off. An interface disconnecting means is provided for disconnecting the communication interface with the corresponding channel device when the means turns on the flag, so that the communication interface between the channel device and the channel control device is disconnected by the cancel command. This makes it possible to easily and quickly cancel the processing by the processing command.

According to the fifth aspect of the present invention, by adopting an interface for communicating with the channel device through the SCSI bus, it is possible to realize commonization of devices and high-speed processing up to cancellation.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing an outline of a computer system using a channel control device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an outline of a processing flow in a computer system using the channel control device of the present embodiment.

FIG. 3 is a flowchart showing a flow of processing of a CPU in the embodiment.

FIG. 4 is a flowchart showing the flow of processing when the channel control device receives a channel command in the present embodiment.

FIG. 5 is a flowchart showing the flow of processing on the semiconductor file device side in this embodiment.

FIG. 6 is a block diagram illustrating an example of a computer system using a semiconductor file device as a channel device.

FIG. 7 is a system configuration diagram showing a computer system that implements command processing according to the first conventional proposal.

FIG. 8 is a block diagram for explaining a suspension process according to a second conventional proposal.

[Explanation of symbols]

 Reference Signs List 11 main controller 21 CPU 27 first DMA controller 28 FIFO memory 31 first MPU 33 second DMA controller 37 first SCSI controller 41 second SCSI controller 46 semiconductor memory 48 second MPU DESCRIPTION OF SYMBOLS 101 Channel control device 102 Semiconductor file device 111 1st interruption flag register 112 2nd interruption flag register

Claims (6)

[Claims] 1. A channel for determining whether a channel command sent from a central processing unit for control of a channel device is a process command for causing the channel device to perform a predetermined process or a cancel command for canceling the process. Command type determining means, channel command buffer means for temporarily storing the channel command determined by the channel command type determining means to be the processing command until processing starts, and A channel device control unit for executing a process by a channel command for the channel device; and a channel command determined by the channel command type determination unit to be the cancellation command without passing through a channel command buffer unit to the channel device control unit. Give cancel command And a completion notifying means for notifying the central processing unit of the cancellation of the corresponding processing by the cancel command supplied by the cancel command supplying means. 2. A channel for determining whether a channel command sent from a central processing unit for controlling a channel device is a process command for causing the channel device to perform a predetermined process or a cancel command for canceling the process. Command type discriminating means; first-in first-out memory means for sequentially storing the channel commands which the channel command type discriminating means has determined to be the processing command until the start of processing; and Channel device control means for executing a process according to a channel command, and a cancellation command supply means for providing the channel command determined by the channel command type determination means to the cancellation command to the channel device control means without passing through a first-in first-out memory means And this cancellation Channel control device characterized by comprising a completion notification unit that notifies the said central processing unit when the corresponding process is canceled by cancel command supplied by the command supplying means. 3. A channel for determining whether a channel command sent from a central processing unit for control of a channel device is a process command for causing the channel device to perform a predetermined process or a cancel command for canceling the process. Command type discriminating means; first-in first-out memory means for sequentially storing the channel commands which the channel command type discriminating means has determined to be the processing command until the start of processing; and Channel device control means for executing a process according to a channel command, a cancellation command storage means for storing the channel command determined by the channel command type determination means to be the cancellation command, and a channel command type determination means for executing the cancellation command. The judge that there is A direct memory access control means for writing a write command to the cancel command storage means by direct memory access and reading the written cancel command to provide the channel device control means; and a cancel command supplied by the direct memory access control means. A channel control device, comprising: a completion notifying means for notifying the central processing unit when a corresponding process is canceled. 4. A channel for determining whether a channel command sent from the central processing unit for controlling a channel device is a process command for causing the channel device to perform a predetermined process or a cancel command for canceling the process. Command type discriminating means; first-in first-out memory means for sequentially storing the channel commands which the channel command type discriminating means has determined to be the processing command until the start of processing; and Channel device control means for executing a process according to a channel command, flag on / off means for turning on a flag when the channel command type determination means determines that the command is the cancellation command, and turning off the flag otherwise; .Off means turns on the flag An interface disconnecting means for disconnecting an interface for communication with a corresponding channel device; and when the interface for communication is disconnected by the interface disconnecting means, a corresponding cancel command is executed for the central processing unit. And a completion notifying means for notifying the user of the fact. 5. The communication interface is a SCSI interface.
An interface for communicating with the channel device through the bus, wherein the interface disconnecting means notifies the channel device via the SCSI bus that the corresponding processing command should be canceled and releases the SCSI bus from the channel device. The channel control device according to claim 4, wherein 6. The channel control device according to claim 1, wherein said channel device is a semiconductor file device.