User manual QUANTUM SCSI MAN CDXXXXXX STDXXXXXX

[. . . ] DDS-4 and DAT 72 Tape Drives and Autoloaders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SCSI Interface Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Copyright © 2003 Certance LLC. All rights reserved Part Number 50000697 June 2003, Rev. B Certance and the Certance logo are trademarks of Certance LLC. Other product names are trademarks or registered trademarks of their respective owners. [. . . ] Last Log Parameter A log parameter is made up of · · · · A two-byte parameter code followed by A Parameter Control byte A Parameter Length byte One or more parameter bytes Parameter Code Field The following table presents the Parameter Code Field format. Page 62 DDS-4 SCSI Interface Manual, Rev. B Bits Byte 0 1 2 3 4 N 7 6 5 4 3 2 1 0 MSB--Parameter Code Parameter Code--LSB Parameter Control Parameter Length (n-3) Parameter Value Parameter Value The Parameter Code field identifies the log parameter being returned to the initiator. If the Parameter Pointer field of the CDB is zero, the parameter code of the first log parameter indicates the first parameter code supported by the drive for this log page. All of the bits in byte 2 of the log parameter are collectively referred to as the Parameter Control byte. The bit descriptions as they are returned by the LOG SENSE command are given in the following table. Bit Name Disable Update (DU) Bytes 2 Bits 7 Description When set (1), this bit indicates that the particular parameter is not to be updated by the drive. This bit is set by the drive when the accumulated value reaches its maximum. It is also returned set if the host set the bit for the last LOG SELECT command. For parameter types other than threshold and accumulated values, this bit is always 0. Disable Save (DS) 2 6 A DS bit of zero indicates that the target supports saving for the specified log parameter. A DS bit of one indicates that the target does not support saving for the specified log parameter in response to Log Select command. Always 0 Always 0 Target Save Disable (TSD) Enable Threshold Comparison (ETC) Threshold Met Criteria Field (TMC) List Binary Information List Parameter (LP) 2 2 2 5 4 3-2 2 2 1 0 The Parameter Length byte is the byte count of the parameter value that follows. The Parameter Value bytes are the actual data requested according to the PC bits of the CDB. Write Error Counts (page 2) Page 2 contains the Write Error counts, which are tabulations of the possible errors (if any) encountered during writing to tape. The page 2 parameter codes for write errors are listed in the following table. Parameter Code 0002 0003 Length 2 3 Name Total rewrites Total errors corrected Commands: Log Sense (4Dh) Page 63 0004 0005 0006 8007 2 8 2 2 Not applicable (always returns 0) Total bytes processed (written) Total uncorrectable errors Rewrites since last read-type operation The total rewrite count is incremented each time a frame sequence is rewritten on tape. Rewrites are used to recover from media errors detected by the RAW (readafter-write) checking feature of the drive. The total errors corrected count is the same as the total rewrite count. The total bytes written count is incremented by the size of each group (in bytes) that is successfully written to tape. This count includes any fill bytes needed to fill a group before the group is written to tape. However, this count does NOT include the count of additional bytes written during rewrites. Also, it is greater than the count of write data bytes transferred to the drive. The total bytes written count includes a total of · · · All user data ECC frames Other structures in the group data (as defined by the DDS format) The total uncorrectable errors count is a tabulation of the times the drive could not correct a write error by any means (including the rewrite retry limit being exceeded). The rewrites since last read-type operation count is similar to the total rewrite count (0002) except the counter is set to 0 in two cases: · · When the operation is changed to a read-type operation. [. . . ] Buffer ID ADRS Byte Transfer Length 2 3-5 6-8 Only Buffer ID 0 is valid If MODE=2, 4, or 5, then ADRS is the offset where data loading begins. The Byte Transfer Length specifies the maximum number of bytes transferred to the drive. If MODE=0, it contains a four-byte header; thus, the data length to be stored in the buffer of the drive is Byte Transfer Length minus 4. A Byte Transfer Length of zero indicates that no data are transferred. [. . . ]