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. Seagate is a trademark of Seagate Technology LLC. [. . . ] The total correctable ECC error count is incremented each time the ECC process corrects one to two erroneous tracks read from the tape. For performance reasons, the ECC process corrects errors rather than retrying if the tracks in error are less than three; otherwise, a reread is performed. Note: This count is a count of the correctable C3 errors ONLY. It does NOT include the C1 or C2 ECC errors normally encountered while reading DDSformatted cassettes. The total bytes read count is incremented by the size of each group (in bytes) that is successfully read from the tape. This count includes overhead bytes (as defined by the DDS format specification) that were read from the group. However, this count does NOT include any additional rewritten frames that were read nor any rereads. Also, it is greater than the count of read data bytes transferred. The total uncorrectable errors count is a tabulation of the times the drive could not correct a read error by any means (including the reread retry limit being exceeded). The rereads since last write-type operation count is similar to the total reread count (0002) except the counter is set to 0 in two cases: · · When the operation is changed to a write-type operation. When a rewind operation is performed. Tape Alert Log Page (page 2Eh) The Tape Alert Log page provides information about errors and status of the drive and media in the form of a flag for the supported Tape Alert Flags. The DDS-4 and DAT 72 drive autoloader conform to the Tape Alert v3. 0 Standard. The Tape Alert Log page can only be accessed by the Log Sense commands, there are no Log Select actions defined in the Tape Alert specification. The log page is used in conjunction with the Tape Alert Mode Page that controls the action taken by the drive when a flag is set and sets various other control mechanisms of the Tape Alert system. A flag is set whenever the condition for setting the flag exists. There are three types of flags, Informational, Warning, and Critical. The type of flag depends upon the severity of the condition that sets the flag. Flags are cleared on the following conditions: · · · · · At drive power on When the TapeAlert Log page is read When specified corrective action has been taken (such as using a cleaning cartridge) On a SCSI bus reset or bus device reset message On Log Select reset (note that the recommended action on receiving Log Select for the TapeAlert Log page is to reject the command with an error Commands: Log Sense (4Dh) Page 65 Additional information regarding the Tape Alert system is found in the SCSI-3 Stream Commands (SSC) Standard. Page 66 DDS-4 SCSI Interface Manual, Rev. B The format of the Tape Alert Log Page is shown below: Bits Byte 0 1 2 3 5n-1 5n 5n+1 5n+2 5n+3 DU(0) DS(1) TSD(0) 0 MSB LSB MSB ­ Parameter Code LSB ­ Parameter Code ETC(0) TMC LBIN(0) LP(0) Parameter Length (1) Value of Flag (set when bit 0 = 1) 0 0 0 0 0 0 0 Page Length (140h) 7 6 5 4 3 2 1 0 There are 64 Tape Alert flags for drives and autoloaders, (some are reserved). The following table lists the flags supported by the drive: No 1 2 3 4 Flag Read Warning Write Warning Hard Error Media W C Type W W Required Host Message The tape drive is having problems reading data. No data has been lost, but there has been a reduction in the performance of the tape. The tape drive is having problems writing data. [. . . ] If MODE=0, the initiator should ensure that the Byte Transfer Length is not greater than 4 plus the Available Length that is returned in the header of the READ DATA BUFFER command. If the Byte Transfer Length is greater than the Available Length plus 4, the drive returns a Check Condition status with a Sense Key of Illegal Request. WRITE DATA BUFFER Data Header The following table shows the layout of the data header Block. Bits Byte 0 1 2 3 7 0 0 0 0 6 0 0 0 0 5 0 0 0 0 4 0 0 0 0 3 0 0 0 0 2 0 0 0 0 1 0 0 0 0 0 0 0 0 0 Page 166 DDS-4 SCSI Interface Manual, Rev. B Completion Status The Completion Status for the WRITE DATA BUFFER command is shown in the following table. Code 00h Message Good Status Description · If Mode = 0, The Data Header is accepted and verified, if correct the data is accepted and written to the buffer at offset 0, the transfer length is the sum of the four byte header and the data to be written in the buffer. · If Mode = 2, the data is written to the buffer starting at the specified offset. [. . . ]