No OperationThe NO-OP message is sent from an initiator to inform the target that no message is valid in response tothe target request for a message. The media changer does not take any action in response to the NoOperation message; it accepts this message and continues processing the current command.Message Parity ErrorThe MESSAGE PARITY ERROR message is sent from the initiator to the target to indicate that one ormore bytes in the last message received contained a parity error.Bus Device ResetThe BUS DEVICE RESET message is sent from an initiator to clear all commands, data, and status at thetarget. When the target recognizes this message, it aborts the command currently being executed,proceeds to the BUS FREE state and executes a soft reset.IdentifyThe IDENTIFY messages are sent either by the initiator or by the target to establish (or reestablish) thelogical connection path between an initiator and target for a particular logical unit.Bit 7 6 5 4 3 2 1 0Byte0 Identify DiscPriv LUNTAR Reserved LUNField Descriptions:Bit 7 - IdentifyThis bit must be set to 1 to indicate this is the Identify message.Bit 6 - DiscPriv (Disconnect Privlege)This bit indicates whether the initiator supports the disconnect privelege, as follows:v 0 - Disconnect is not allowedv 1 - Disconnect is allowedThe media changer always sets this bit to 0. Only initiators indicate if they support disconnect.Bit 5 - LUNTAR (Logical Unit Target)This bit indicates the LUNs that you can access on this device. This bit must be set to 0 toindicate that the Identify message is directed to a logical unit.Bit 2 ..0 - LUN (Logical Unit Number)The only supported logical unit number for the media changer is 1. If the LUN fiels is set to a othervalue than 0, the media changer returns Check Condition status to commands other thanINQUIRY and REQUEST SENSE, and the sense data is set to indicate that the logical unit is notsupported.Chapter 4. Messages 4-3
