scsi interface specification - Plasmon

LASER-DRIVE SCSI CHARACTERISTICS MESSAGE SYSTEM SPECIFICATIONNo Operation 08HThis message is sent from an Initiator in response to the LaserDrive's request for a message when theInitiator does not currently have any other valid message to send.Message Parity Error 09HThis message is sent from the Initiator to the LaserDrive to indicate that one or more bytes in the lastmessage it received had a parity error.In order to indicate its intentions of sending this message, the Initiator asserts the ATTN signal prior to itsrelease of ACK for the REQ/ACK handshake of the message that has the parity error. This provides aninterlock so that the LaserDrive can determine which message has the parity error.If the LaserDrive receive this message under any other circumstance, it will signal a catastrophic errorcondition by releasing the BSY signal without any further information transfer attempt. Should this occurduring the course of a command, the LaserDrive will create sense data with the ABORTED COMMANDSense Key and an error code of Inappropriate Message Error.Device Reset 0CHThis message is sent from an Initiator to direct the LaserDrive to clear all current commands on that SCSIdevice. This message forces the SCSI device to an initial state with no operations pending for any Initiator.Upon recognizing this message, the LaserDrive shall go to the BUS FREE phase.Terminate I/O Process 11HThis message is sent from the Initiator to the LaserDrive to advise the LaserDrive to terminate the currentI/O process without corrupting the media. Upon successful receipt of this message and after emptying theLaserDrive data buffer, the LaserDrive will terminate the I/O process and return a COMMANDTERMINATED status. The sense key will be set to NO SENSE and the additional sense code and qualifierwill be set to I/O PROCESS TERMINATED.Only commands that have data transfers associated with them will accept the TERMINATE I/O PROCESSmessage. The valid bit will be set to one and the information field will be set as follows:1) If the command descriptor block specifies an allocation length or parameter list length in bytes, theinformation field will be set to the difference (residue) between the transfer length and the numberof bytes transferred.2) If the command descriptor block specifies a transfer length field, the information field will be asdefined in the REQUEST SENSE command. The LaserDrive ignores the Terminate I/O Processmessage and terminates current I/O commands when any error is detected while emptying it'sdata buffer on a write, or when an internal controller error occurs. Current I/O commands areterminated with the appropriate error status and sense data for the error condition.The LaserDrive ignores the TERMINATE I/O PROCESS message and terminates thecommand in a normal manner, if the LaserDrive completes all processing (i.e. all data hasbeen transferred to or from the Initiator) for the command and a TERMINATE I/OPROCESS message is received.If the LaserDrive receives a TERMINATE I/O PROCESS message before or during theCommand Phase, the LaserDrive will set the valid bit in the sense data to zero andterminate the I/O process with COMMAND TERMINATED status. The sense key will beset to NO SENSE and the additional sense code and qualifier will be set to I/O PROCESSTERMINATED.PLASMON L M S - LD 6100/LF 6600/LF 6602 SCSI INTERFACE SPECIFICATIONPage 14