JP2002373122A - Scsi interface controller and its selection monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the SCSI interface controller of a host adapter capable of preventing the deterioration of any input and output processing performance with respect to peripheral equipment in an on-line state by confirming the connected situation to peripheral equipment in an off-line state. SOLUTION: This SCSI interface controller is provided with a selection delay monitoring time selecting circuit 300 so that a selection time-out delay time with respect to peripheral equipment whose selection has been successful and a selection time-out delay time with respect to peripheral equipment whose selection has failed can be set. The selection time-out delay time of an SCSI command with respect to the peripheral equipment whose selection has been successful is set so as to be not less than 250 milliseconds based on the SCSI specifications of an ANSI, and the selection time-out delay time with respect to the peripheral equipment whose selection has failed is set so as to be short until the selection of the peripheral equipment is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a SCSI interface control device and a selection monitoring method thereof, and more particularly to a SCSI interface control device in which a host adapter connected in a daisy chain configuration is improved and a selection monitoring method using the SCSI interface control device. .

[0002]

2. Description of the Related Art Conventionally, this SCSI interface controller has a SCSI interface provided in a peripheral device for a computer, and connects the SCSI interface of a host computer or a peripheral device via a SCSI bus to the SCSI interface.
I system was configured.

In such a SCSI system,
The selection timeout / delay monitoring time of the host adapter is set at a minimum of 250 milliseconds to control connected peripheral devices.

Conventionally, as a peripheral device interface, a SCSI (SMALL COMPUTER SYSTEM) has been used.
MINTERFACE) standard has been standardized by ANSI. In the following description, this SCSI
An interface conforming to the standard is called a SCSI interface.

[0005] All operations on SCSI can be subdivided into units called bus phases. Bus-free phase, arbitration
Phase, selection phase, reselection
Eight types, a phase, a command phase, a data phase, a status phase, and a message phase are defined.

[0006] In the selection phase,
If there is no response of the BSY signal from the target even after a lapse of a time equal to or longer than the selection timeout delay, timeout processing is performed to release the bus. ANSI recommends 250 milliseconds for the selection time-out delay monitoring time.

[0007]

In this type of prior art, in a configuration in which a plurality of peripheral devices are daisy-chain connected under a host adapter, SCSI IDs are assigned, but peripheral devices in an offline state are not assigned. If there is, the host adapter periodically performs selection on the peripheral device in the offline state to check the connection status, and the SCSI bus is used for at least 250 milliseconds, which is the selection timeout / delay monitoring time. And the input / output processing of peripheral devices in the online state is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a host adapter SCSI interface control device and its selection monitoring method for preventing a decrease in input / output processing performance with respect to an on-line peripheral device by confirming a connection status with an off-line peripheral device. To provide.

[0009]

According to a first embodiment of the present invention, in a system in which a host adapter and a peripheral device are connected, a selection time-out / delay monitoring time is changed depending on a connection state with the peripheral device. A SCSI interface control device is provided, comprising:

According to a second embodiment of the present invention, in a selection process of a system in which a host adapter and a peripheral device are connected, a SCSI ID to be selected is selected.
A means for changing a selection timeout / delay monitoring time depending on a connection state with the SCSI interface control device.

In a third embodiment of the present invention, there is provided a selection delay monitoring time selection circuit for selecting a selection time-out delay monitoring time according to a connection state of a peripheral device when a SCSI command is issued in a peripheral device state monitoring process. SCSI that is provided
A selection monitoring method for an interface control device is provided.

[0012] In a fourth embodiment of the present invention, the selection delay monitoring time selection circuit comprises: a SCSI ID for performing selection; a selection success register connected to the SCSI ID; and a selection timeout of SCSI command. A plurality of selection time-out delay monitoring time registers for setting a delay value, a selection switch connected to the selection success register and selecting the plurality of selection time-out delay monitoring time registers, and a selection switch selected by the selection switch And a SCSI command issuing circuit for issuing a selection timeout delay value. 4. A selection monitoring method for a SCSI interface control device according to claim 3, wherein

The fifth embodiment of the present invention enables setting of a selection timeout delay time for a peripheral device for which selection has been successful and a selection timeout delay time for a peripheral device for which selection has failed. The selection timeout delay time of the SCSI command for the peripheral device is set to 250 ms or more in accordance with the ANSI SCSI standard, and the selection timeout delay time for the peripheral device in which the selection fails is set to the time that the peripheral device can select. 5. A selection monitoring system for a SCSI interface control device according to claim 4, further comprising means for setting a short setting.

The sixth embodiment of the present invention is characterized in that the occupation time of the SCSI bus by the selection time-out delay monitoring time is shortened, and the delay of input / output processing to peripheral devices for which selection has been successful is reduced. A selection monitoring method for a SCSI interface control device according to claim 5 is provided.

[0015]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. Referring to FIG. 1, an embodiment of the present invention shows a configuration in which a host adapter 100 and two peripheral devices 200 to 201 are connected by a SCSI bus 400.

One embodiment of the present invention includes a host adapter 100 for controlling a magnetic tape device and the like, a plurality of peripheral devices 200 to 201 such as a magnetic tape device, and a host adapter 10.
0 and a peripheral device 200-201.

The host adapter 100 includes a CPU (Central Processing Unit) 101 constituting a control unit of the host adapter,
ROM (read only memory) storing microcode for PU101 to control the host adapter
103, a RAM (random access memory) 102 provided with a memory or the like used by the CPU 101 for each type of data processing, and data from the CPU 101
SCSI interface 10 that converts the data into a protocol and transfers it to the SCSI bus 400 to communicate with peripheral devices
4 is provided.

The SCSI interface 104 is provided with a selection / timeout / delay monitoring time selection circuit 300.

A control command generated by the CPU 101 of the host adapter 100 is supplied to a SCSI interface 104, converted into a SCSI protocol, and its output is
A SCSI interface 210 connected to the peripheral device selected by the CPU 101 through the CSI bus 400,
The processing is performed at 211 to control the peripheral devices 200 and 201.

The peripheral devices 200 to 201 are connected to the SCSI bus 400 and communicate with the host adapter 100.
20 to 221.

The control command generated by the CPU 101 is:
The data is supplied to the SCSI interface 104 and converted into a SCSI protocol. The output is processed by the SCSI interfaces 210 and 211 connected to the peripheral device selected by the CPU 101 via the SCSI bus 400 to control the peripheral devices.

According to the present invention, the SCSI interface 104 is provided with a selection timeout / delay monitoring time selection circuit 300.

The selection time-out delay monitoring time selection circuit 300 is used to select an SCS for a peripheral device.
It functions in the selection processing which is a part of the I command issuance processing. The functions in this selection process are:
Selection / selection depends on the connection status between the peripheral device which is the target device of the SCSI command issuance and the host adapter 100.
A timeout delay value is determined, and a SCSI command is issued.

Referring to FIG. 2, the selection delay monitoring time selection circuit 300 inside the SCSI interface 104 (FIG. 1) performs the SCSI
An ID 310, a selection success register 320 connected to the SCSI ID 310, a plurality of selection timeout delay monitoring time registers 330 for setting a selection timeout delay value of a SCSI command, and a selection success register 320. , A selection switch 340 for selecting a plurality of selection timeout delay monitoring time registers 330, 331, and a SCSI command issuing circuit 350 selected by the selection switch 340 and issuing a selection timeout delay value. .

SCSI ID 310 for selection
Is the S corresponding to the peripheral device that issues the SCSI command.
The CSI ID value is entered.

The selection success register 320 contains the SC
Flag 3 indicating success or failure of selection for each SI ID
SCSI ID 31 for storing and performing selection
The selection success flag 321 corresponding to 0 is output to the selection switch 340. Also, using the selection success signal 351 from the SCSI command issuing circuit 350,
The selection success flag 321 is set.

In the selection timeout delay monitoring time register 330, a selection timeout delay value of a SCSI command for a peripheral device that has been successfully selected is set. In the selection timeout delay monitoring time register 331, a selection timeout delay value of a SCSI command for a peripheral device in which selection has failed is set.

The selection switch 340 is based on the output signal 322 from the selection success register 320 and selects the selection time-out delay monitoring time register 330.
Then, an appropriate register value is selected from the selection timeout delay monitoring time register 331, and the selection timeout delay value 341 is output. This means that if the output signal 322 from the selection success register 320 has been successfully selected, the selection
If the timeout / delay monitoring time register 330 is selected and the output signal 322 fails in selection, the selection / timeout / delay monitoring time register 33 is selected.
Select 1.

In the SCSI command issuing circuit 350, the selection timeout delay value is
The selection time-out delay value 341 selected by the selection switch 340 is input, and a SCSI command issuance process is performed. Further, whether or not the selection is successful as a result of issuing the SCSI command to the peripheral device is transmitted to the selection success register 320 using the selection success signal 351.

Next, the operation of this embodiment will be described. First, a conventional state monitoring operation for a peripheral device in an offline state will be described with reference to a timing chart of FIG.

In FIG. 3, since the selection timeout delay time is 250 milliseconds or more of the SCSI standard, description will be made assuming that the operation is set to 250 milliseconds.

SC for a peripheral device in an offline state
Since this command is issued, there is no response from the peripheral device unless it goes online.
The Y signal remains asserted for the selection timeout delay monitoring time of 250 milliseconds. During this time, since the SCSI bus is occupied, input / output operations to other peripheral devices cannot be performed.

On the other hand, the state monitoring operation for the offline state according to the present invention is executed according to the timing chart of FIG.

A peripheral device that is not performing any operation in the online state responds to the selection in at least 1 millisecond. Therefore, the present invention will be described on the assumption that the selection timeout delay value is set to 1 millisecond for the peripheral device in the off-line state.

SCS for peripheral devices in offline state
As described above, the I command is issued occupies the SCSI bus of the selection timeout delay monitoring time of 1 millisecond, but the delay of the input / output operation with respect to other peripheral devices is significantly longer as compared with the conventional 250 milliseconds. I'm preventing.

The control operation for setting the selection time-out delay value will be described with reference to the block diagram of FIG. 2 and the flowchart of FIG. First, as an initial setting, the selection time-out delay monitoring time register 330 stores in the selection successful S
A selection timeout delay value of 250 milliseconds corresponding to the CSI ID is set, and a selection timeout delay monitoring time register 331 is set.
Is set to 1 ms, which is the selection timeout delay value corresponding to the SCSI ID for which selection has failed (step A0 in FIG. 5). The next S
Step A0 is not performed after the CSI command is issued.

SCSI ID 310 for selection
Is input to the selection success register 320, and the SCSI I
The selection success flag 321 corresponding to D is output from the output signal 322 to the selection switch 340 (steps A1 and A2 in FIG. 5).

The selection switch that has received the output signal 322 of the selection success register 320 changes the value of the selection / timeout delay monitoring time register 330 if the value of the output signal 322 is successful (step A3 in FIG. 5). Output to the SCSI command issuing circuit 350 as the timeout delay value 341 (step A4 in FIG. 5), and if the value input from the selection success register is selection failure (step A3 in FIG. 5), select timeout delay The value of the monitoring time register 331 is output to the SCSI command issuing circuit 350 as the selection timeout delay value 341 (step A5 in FIG. 5).

The SCSI command issuing circuit 350 uses the selection timeout delay value 341 as the selection timeout delay value,
An SI command issuance process is performed and the command is issued to the peripheral device corresponding to the SCSI ID (step A6 in FIG. 5).
In addition, a selection success signal 3 indicates whether or not the selection is successful as a result of issuing the SCSI command to the peripheral device.
Send to the selection success register 320 using 51.

In the selection success register 320 which has received the selection success signal, the selection success flag corresponding to the SCSI ID is set and released (steps A7, A8 and A9 in FIG. 5).

As described above, the selection timeout / delay monitoring time is varied at the time of issuing the SCSI command according to the connection state between the peripheral device to be monitored and the host adapter. , A selection timeout delay value responsive to a normal operation can be set in the peripheral device in the offline state.

Accordingly, by setting the time for occupying the SCSI bus as short as possible to less than 250 milliseconds when monitoring the status of the peripheral device in the off-line state, it is possible to prevent the delay of the input / output time for the peripheral device in the online state. Can be

In another embodiment of the present invention, the basic configuration is as described above, but as shown in FIG. 6, the number of controllable devices is further devised. 6, in another embodiment of the present invention, a selection time-out delay monitoring time selection circuit 600 is provided in the SCSI interface (FIG. 1).

The selection time-out delay monitoring time selection circuit 600 includes a peripheral device (# 1 to #N).
The selection process, which is a part of the SCSI command issuance process, functions. The function of this selection processing is to determine the selection timeout delay value according to the connection state between the peripheral device which is the target device of the SCSI command issuance and the host adapter 100 (FIG. 1).
Issue SI command.

Referring to FIG. 6, the selection delay monitoring time selection circuit 600 inside the SCSI interface 104 (FIG. 1) performs the SCSI
ID 610, a selection success register 620 connected to the SCSI ID 610, and an output signal 6
22, a plurality of selection timeout delay monitoring time registers 630 and 631 for setting a selection timeout delay value of a SCSI command.
And a selection switch 640 connected to the selection success register 620 and selecting a plurality of selection time-out delay monitoring time registers 630 and 631. Further, the selection delay monitoring time selection circuit 600 includes a SCSI command issuing circuit 350.
It is connected to the. This SCSI command issuing circuit 65
0 inputs the selection time-out delay value 641 selected by the selection switch 640, and transmits to the selection success register 620 using the selection success signal 651 whether or not the selection is successful as a result of issuing the SCSI command to the peripheral device. And is configured to issue a selection timeout delay value. As described above, in another embodiment of the present invention, the number of peripheral devices is increased from two to N. Further, the number of selection success flags 621 corresponding to the SCSI IDs in the selection success register is increased to N. As a result, it is possible to increase the number of peripheral devices capable of changing the selection time-out delay value depending on the connection state with the peripheral device.

[0047]

As described above, according to the present invention,
Regarding the SCSI interface control device, based on the basic configuration in which the host adapter and a plurality of peripheral devices are connected in a daisy-chain configuration, a SCSI interface control on the host adapter side is realized which suppresses a decrease in input / output performance by monitoring the status of the peripheral devices. An apparatus is provided.

Further, according to the present invention, the selection monitoring of the SCSI interface control device provided with a circuit for selecting the selection timeout / delay monitoring time according to the connection status of the peripheral device at the time of issuing the SCSI command in the status monitoring process of the peripheral device. A scheme is provided.

The selection monitoring method of the SCSI interface control device includes a selection timeout delay time for a peripheral device for which selection has been completed and a selection timeout for peripheral devices for which selection has failed.
The timeout delay time can be set, and the selection timeout delay time of the SCSI command for the peripheral device for which the selection has been completed is ANS.
Set at 250 ms or more according to the SCSI standard of I,
By performing the operation of setting the selection timeout delay time for the peripheral device that has failed the selection short enough to allow the peripheral device to select,
The effect of shortening the occupation time of the SCSI bus by the selection time-out delay monitoring time is to reduce the delay of input / output processing for peripheral devices for which selection has been successful.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a SCSI system according to an embodiment of the present invention.

FIG. 2 shows a selection method according to an embodiment of the present invention.
FIG. 4 is a block diagram illustrating a timeout / delay monitoring time selection circuit.

FIG. 3 is a diagram showing a timing of a BSY signal in a SCSI bus during a state monitoring operation for a peripheral device in an off-line state in the related art.

FIG. 4 is a diagram showing the timing of a BSY signal in a SCSI bus during a state monitoring operation for a peripheral device in an offline state according to the present invention.

FIG. 5 is a diagram illustrating a selection timeout,
It is a figure showing a flow chart of a delay value control operation.

FIG. 6 is a block diagram showing a selection timeout delay monitoring time selection circuit according to another embodiment of the present invention.

[Description of Signs] 100 Host adapter 101 CPU 102 RAM 103 ROM 104 SCSI interface 200 Peripheral device # 0 201 Peripheral device # 1 202 Peripheral device # 2 20N Peripheral device #N 210 SCSI interface # 0 211 SCSI interface # 1 220 Peripheral device # 0 221 Peripheral device # 1 300,600 Selection timeout delay monitoring time selection circuit 310,610 SCSI ID 320,620 for selection Selection success register 321, 621 Selection success flag 322,622 Output signal 330 of selection success register 320 , 630 Selection timeout delay monitoring time register 331, 631 Selection timeout delay monitoring time register 340,640 selection switch 341,641 Selection timeout delay value 341 350,650 SCSI command issuing circuit 351,651 selection success signal 400 SCSI bus

Claims (6)

[Claims] 1. A SCSI interface control device in a system in which a host adapter and a peripheral device are connected, further comprising means for changing a selection timeout / delay monitoring time according to a connection state with the peripheral device. 2. In a selection process of a system in which a host adapter and a peripheral device are connected, a means for changing a selection timeout / delay monitoring time according to a connection state with a SCSI ID to be selected is provided. Selection monitoring method for SCSI interface controller. 3. SCS in the peripheral device status monitoring process
A selection monitoring method for a SCSI interface control device, comprising a selection delay monitoring time selection circuit for selecting a selection timeout monitoring time according to a connection state of a peripheral device when an I command is issued. 4. The selection delay monitoring time selection circuit sets a SCSI ID for selection, a selection success register connected to the SCSI ID, and a selection timeout delay value of a SCSI command. A selection time-out delay monitoring time register, a selection switch connected to the selection success register for selecting a plurality of selection time-out delay monitoring time registers, and a selection time-out delay value selected by the selection switch 4. The selection monitoring method for a SCSI interface control device according to claim 3, further comprising a SCSI command issuing circuit that performs the selection. 5. A selection timeout delay time for a peripheral device for which selection has been successfully completed and a selection timeout delay time for a peripheral device for which selection has failed, and a selection timeout of a SCSI command for a peripheral device for which selection has been successful.・ Delay time is ANSI SC
5. A method according to claim 4, wherein the setting is made at least 250 milliseconds in accordance with the SI standard, and a means for setting a selection timeout delay time for a peripheral device in which selection has failed to be as short as possible for the peripheral device to be selected.
The selection monitoring method of the SCSI interface control device described in the above. 6. The SCSI interface control device according to claim 5, wherein the occupation time of the SCSI bus by the selection time-out delay monitoring time is shortened, and the delay of the input / output processing to the peripheral device for which the selection has been successful is reduced. Selection monitoring system.