JP2502874B2 - SCSI system and command support confirmation method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a SCSI (Small Computer System Int) that is an initiator or a target.
The present invention relates to a system (hereinafter, referred to as a SCSI system) in which a plurality of devices conforming to the erface standard are connected by a SCSI bus, and particularly to a technique for confirming a command supported by a target on the initiator side.

[0002]

2. Description of the Related Art An initiator (usually a host computer) of a SCSI system issues an inquiry command at system startup (immediately after power-on and at system initial), and returns data from the target. Can analyze the target type (hard disk device, printer, scanner, etc.) on the SCSI bus. Then, if the type of the device is known, the (mandatory) command that is necessarily supported by the device can be easily recognized from the SCSI standard.

However, with regard to the optional command, even if the device is a SCSI standard, the command supported by the manufacturer and model of the device is different. I can't verify whether or not the command is actually supported.

Therefore, conventionally, when the initiator side wants to use an option command, as shown in FIG. 3, the command is transmitted to the target (process 111), the status from the target is received (process 112), and the command is transmitted. It is checked whether or not the status is good (process 113). If the status is good, the initiator determines that the target supports the command.

If the status from the target is not a good status, a check condition (check co
ndition) status is checked (process 114).
If it is the check condition status, it means that the target side has handled it as an error. Therefore, the initiator transmits a request sense (Request Sense) command (process 115), receives sense data from the target (process 116), and then continues. The status corresponding thereto is received (process 117). It is confirmed that this status is a good status (process 118), and the received sense data is analyzed (process 119). By this analysis, the command of interest transmitted last time (process 111
The command finally sent is confirmed to be invalid, and it is finally determined that this command is not supported.

[0006]

As described above, whether or not each optional command is supported is confirmed by actually transmitting the command on the initiator side and analyzing the error information. The method is that the SCSI bus is often used for confirmation, and when there are many optional commands or targets that need confirmation, how often and how long the SCSI bus is used for confirmation. Is quite large. Furthermore, SC
When there are multiple initiators on the SI bus, the frequency and time of each initiator increase proportionally because each initiator performs the same confirmation.

However, since the SCSI bus is a daisy-chained bus, the SCSI bus is completely occupied during the confirmation of the command support. Therefore, the above-mentioned command support confirmation method uses the efficiency of the SCSI bus and the system throughput. May be significantly deteriorated.

The present invention has been made in view of the above problems, and in a SCSI system, a command supported by a target is issued on the initiator side without deteriorating the usage efficiency of the SCSI bus and the throughput of the system. The purpose is to be able to confirm.

[0009]

In order to solve the above-mentioned problems, the present invention serves as an initiator or a target, S
In a SCSI system in which a plurality of devices conforming to the CSI standard are connected by a SCSI bus, for exchanging command list data related to at least one option command supported by the target between at least one initiator and at least one target. Means for processing a specific command of Then, the initiator issues the specific command to the target, receives the command list data from the target, and associates the data representing the content (the received command list data itself or the data processed into a table) with the target. After saving, the initiator refers to the saved data,
At least the option command is configured to check whether it is supported by the target.

[0010]

According to the present invention, with the above-described configuration, it is only necessary to execute the processing of the specific command once between the initiator and the target, and at least the option command can be confirmed on the initiator side on the initiator side. Therefore, even if there are many optional commands that you want to check, or if there are many targets or initiators on the SCSI bus, the frequency and time of occupying the SCSI bus for command support confirmation can be significantly reduced, and bus usage efficiency and system -It is possible to avoid deterioration of throughput.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a SCSI according to an embodiment of the present invention.
It is a schematic block diagram of a system. In this SCSI system, on the SCSI bus 1, host computers 2 and 3 (generally referred to as initiators), which are initiators, hard disk devices 4, 5 and 6, which are targets, a printer 7, a scanner 8 and a communication device 9 (these are It is a configuration in which daisy chains are used to connect the target).

Each initiator 2, 3 and each target 4
9 to 9 each include a control unit (or a SCSI adapter) for protocol control conforming to the SCSI standard, and the basic function and configuration are similar to those of the conventional SCSI.
It is similar to the standard device.

Although the targets 4 to 9 support the commands corresponding to the respective device types as in the conventional case, even if the same type of device is used, the option command can be changed depending on the manufacturer or the model. There is a difference. For example, the targets 4, 5, and 6 are all hard disk devices, but if the models or manufacturers differ, the option commands to be supported usually differ.

Therefore, when the system is started up, the initiators 2 and 3 issue an inquiry command to each target and analyze the returned data in the same manner as in the conventional case, and each target 4 to 9 is analyzed.
It is possible to recognize from the SCSI standard the types of and the supported mandatory commands.
It is necessary to confirm the option command supported by 9 separately.

Therefore, in this embodiment, in order to efficiently check whether or not the option command is supported, each of the targets 4 to 9 is supported between the initiators 2 and 3 and the targets 4 to 9. A special command (referred to as a support command sense command) for exchanging the list data of the option commands is defined, and the command processing unit 10 (software and / or hardware) for processing this command is the initiator. 2, 3 and targets 4-9.

The command processing unit 10 is most preferably added to all of the initiators 2 and 3 and the targets 4 to 9 as shown in the figure, but may be added only to some of the initiators or targets. . At least for the initiator and target to which the command processing unit 10 is added, it is possible to confirm the efficient support of optional commands according to the present invention. Also, with respect to the other initiators or targets, it is possible to confirm the support of the option command by the above-mentioned conventional method.

Next, the exchange process of the option command list data using the support command sense command will be described. FIG. 2 is a flowchart thereof.

The initiator (assuming the host computer 1) selects a target (assuming the hard disk device 4), issues a support command sense command to the SCSI bus 1 (process 101), and receives it at the target 4. (Process 102).

When the target 4 confirms that the received command is a support command sense command (process 103), it creates list data of option commands supported by its own device and sends it to the SCSI bus 1 (process 104), and the data is received by the initiator 1 (process 105).

When the target 4 finishes transmitting the list data normally, it sends out a good status (process 6), and then the command complete (Command Complet).
e) Issue a message (process 7) and complete the command process.

The initiator 1 receives the stator from the target 4 (process 108), confirms that it is in the good status (process 109), and processes the received list data as it is or in a table or the like. Then, it is stored in the internal memory 12 (FIG. 1) in association with the target 4 (process 110), and this command process is completed.

The command processing unit 10 of the initiator 2 and the target 4 cooperates with the standard SCSI protocol control unit (or adapter) in the processing specific to the support command sense command in the processing described above. .

After exchanging the list data as described above, the initiator 2 causes the confirmation processing unit 11 (FIG. 1) to cause the memory 12 to operate.
The option command supported by the target 4 can be confirmed by referring to the data corresponding to the target 4 stored in the. For example, when it is desired to use a certain option command for the target 4, it is possible to refer to the stored data in the memory 12 and check whether or not the option command is included in the supported option commands. The confirmation processing unit 11 as described above
It can be easily realized by software.

The list data of the mandatory commands may be added to the data exchanged in the support command sense command process.

[0026]

As is apparent from the above description, the present invention provides a specification for exchanging command list data relating to at least option commands supported by at least one initiator and at least one target. The initiator has means for processing the command, the initiator issues the specific command to the target, receives the command list data from the target, and represents the contents of the data (the received command list data itself, or data processed into a table, etc.). ) Is stored in association with the target, and thereafter, the initiator refers to the stored data,
At least it is possible to check whether or not the target supports the option command, so even if there are many option commands to check, S
SC for command support confirmation even if there are many targets or initiators on the CSI bus
This has the effect of significantly reducing the frequency and time of occupying the SI bus, and avoiding deterioration of bus utilization efficiency and system throughput.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing processing of a support command sense command in the SCSI system.

FIG. 3 is a flowchart showing a conventional command support confirmation process.

[Explanation of symbols]

 1 SCSI Bus 2, 3 Host Computer (Initiator) 4, 5, 6 Hard Disk Device (Target) 7 Printer (Target) 8 Scanner (Target) 9 Communication Device (Target) 10 (10a-10h) Command Processing Unit 11 (11a, 11b) Confirmation processing unit 12 (12a, 12b) memory

Claims (2)

(57) [Claims] 1. An initiator or a target,
To exchange command list data relating to at least option commands supported by the target between at least one initiator and at least one target in a SCSI system in which a plurality of devices conforming to the SCSI standard are connected by a SCSI bus. A SCSI system comprising means for processing a specific command of. 2. An initiator or a target,
In a SCSI system in which a plurality of devices conforming to the SCSI standard are connected by a SCSI bus,
A specific command for exchanging command list data regarding at least option commands supported by the device on the SI bus is defined, and the initiator issues the specific command to the target, receives the command list data from the target, and receives the contents. A command support confirmation method characterized in that the data to be represented is stored in association with the target, and thereafter, whether or not at least the option command is supported by the target is confirmed by referring to the stored data. .