User manual QUANTUM DLT2000

[. . . ] ® DLT2000/DLT2500/DLT2700 Cartridge Tape Subsystem Product Manual Date: 19 January 96 Order Number: 81-109132-03 Quantum reserves the right to make changes and improvements to its products, without incurring any obligation to incorporate such changes or improvements in units previously sold or shipped. You can request Quantum publications from your Quantum Sales Representative, or order them directly from Quantum. Publication Number: 81-109132-03 SERVICE CENTERS Quantum Service Center 715 Sycamore Avenue Milpitas, California 95035 Phone (408) 894-4000 Fax: (408) 894-3218 Quantum Gmbh Genferstrasse 4B 60437 Frankfurt am Main 56 Germany Phone: (49) 69-509-1080 Fax: (49) 69-509-10891 Quantum Asia-Pacific Pte. 50 Tagore Lane #b1-04 Singapore, 2678 Phone: (65) 450-9333 Fax (65) 452-2544 CompacTape DLT is a trademark of Quantum Corporation. is a trademark of Quantum Corporation. Copyright 1996 by Quantum Corporation. [. . . ] On properly configured SCSI buses, parity errors should be extremely rare. If any are detected, they should be quickly addressed by improving the configuration of the SCSI bus. A well configured SCSI system in a normal environment should be virtually free of bus parity errors Bus parity errors cause the drive to either retry the operation, go to STATUS phase, or go to bus free and prepare Sense Data (see section 6. 1. 1 in the SCSI-2 specification). Retrying of parity errors during Data Out Phase when writing is normally not done, but can be enabled by changing the EnaParErrRetry parameter in the VU EEROM Mode Page. This feature is not enabled by default because of negative impacts on device performance (the data stream on writes cannot be pipelined as well). DLT2000/DLT2700 Cartridge Tape Subsystem 8-7 DLT2000 SCSI Interface 8. 3 SCSI Message System The message system allows communication between an initiator and a target for the purpose of physical path management. To support certain SCSI-1 initiators, an Identify message is not required by the DLT2000. If a message is sent by the initiator after the SELECTION phase, it should be an IDENTIFY, ABORT, or BUS DEVICE RESET message. If the DLT2000 receives any other message in this case, it will go directly to BUS FREE phase. The following messages are supported: Table 8-1 Supported SCSI Messages Code In/Out Description Section 06 0D 0C 0E 00 04 01 Out Out Out Out In In Both 08-FF 05 0A 0B 09 07 08 03 02 Both Out In In Out Both Out In In ABORT ABORT TAG BUS DEVICE RESET CLEAR QUEUE COMMAND COMPLETE DISCONNECT EXTENDED MESSAGE (SDTR only and wide Data Transfer Request-See note) IDENTIFY INITIATOR DETECTED ERROR LINKED COMMAND COMPLETE LINKED COMMAND COMPLETE w/flag MESSAGE PARITY ERROR MESSAGE REJECT NO-OP RESTORE POINTERS SAVE DATA POINTER ABORT (06h) ABORT TAG (0Dh) BUS DEVICE RESET (0Ch) CLEAR QUEUE (0Eh) COMMAND COMPLETE (00h) DISCONNECT (04h) ExtENDED MESSAGE (01h) IDENTIFY (80h-FFh) INITIATOR DETECTED ERROR (05h) LINKED COMMAND COMPLETE (0Ah) LINKED COMMAND COMPLETE, with flag (0Bh) MESSAGE PARITY ERROR (09h) MESSAGE REJECT (07h) NO-OP ( NO OPERATION)(08h) RESTORE POINTERS (03h) SAVE DATA POINTER (02h) 8-8 DLT2000/DLT2700 Cartridge Tape Subsystem DLT2000 SCSI Interface ABORT (06h) This message is sent from the initiator to the target to clear, on the selected unit, the current I/O process. The target goes directly to the BUS FREE phase after successful receipt of this message. Current settings of Mode Select parameters and reservations are not affected. This message can be sent to a logical unit that is not currently performing an operation for the initiator. If no unit has been selected, the target goes to BUS FREE and no commands, data, or status on the target is affected. ABORT TAG (0Dh) This message is sent from the initiator to the target to clear, on the selected unit, the current I/O operation only. The target goes directly to the BUS FREE phase after successful receipt of this message. Current settings of Mode Select parameters and reservations are not affected. BUS DEVICE RESET (0Ch) This message from an initiator clears all commands, data, and status in the tape controller. When it recognizes this message, the drive flushes the cache to tape and proceeds to the BUS FREE state. The drive then executes a hard reset which leaves it as if a Bus Reset had occurred. CLEAR QUEUE (0Eh) This message clears all I/O processes for all initiators. A Unit Attention condition will be generated for all other initiators that had outstanding I/O processes, with Additional Sense Code (ASC) of Command Cleared by Another Initiator. The target goes directly to the BUS FREE phase after successful receipt of this message. [. . . ] last packet byte Packet Sequence Number / / / / / 0 Figure D-1 EEROM Log Area Layout Table D-1 EEROM LOG Packet Types Packet Type 0 1 2 3 4 5 Purpose Packet Empty Bugcheck - Fatal System Crash PO/ST (power on/self test) Failure EVENT LOG - Generic event informational (non-fatal) data CUP - Code Update Status Packet Manufacturing DIAG results packet D. 2 Bugcheck Packets Bugchecks occur because of some kind of software detected fatal failure. For example, a hardware failure, or an internal system consistancy failure might cause a bugcheck. A full listing is not given here because most are not meaningful without a detailed knowledge of the firmware design. Analysis of the other informtion saved in an EEROM Bugcheck log entry also requires in-dpth internal firmware knowledge to interpret and attempt to determine if the cause was external (e. g. [. . . ]