Command Sequence

This chapter describes about command and phase sequence related to host system. SCSI-2 introduced PHASE, MESSAGE system, etc., for interfacing other than simple command passing, therefore, a lot of sequences can be considerable. Below shows some typical case and out recommendations of implementation SCSI protocol to the system.

System Initialization

The following list of information is assumed necessary and sufficient for normal system initialization:

1)A list of each installed and powered on SCSI device for each SCSI address. SCSI devices that are not powered on are treated as not installed, assuming that the terminators are powered from a source other than unexpected SCSI devices.

2)A list of the installed logical units for each SCSI device. Unpowered or failing logical units may not be completely identifiable.

3)The device type for each available logical unit.

4)The manufacturer and model for each available logical unit. (this information may not be available for SCSI-1 devices)

5)The critical device type information for each available logical unit.

6)This information varies depending on the device type.

7)Extended functionality of SCSI devices such as target role capability in

8)devices that are principally initiators, AEN capability, etc.

The following states are established for each attached logical unit that has power available and is not failing:

1)The ready state for each available logical unit, including any required medium initialization, but not initialization, but not formatting.

2)All error conditions associated with the starting process are cleared.

3)All UNIT ATTENTION conditions are cleared.

4)All data transfer parameters are established.

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M3099GX/GH OEM Manual