User's Guide

Page 86 DDS-4 SCSI Interface Manual, Rev. B
Test and DExcpt bits are set to one and Test Flag Number set to zero, then the
MODE SELECT command will return Check Condition, with sense key set to Illegal
Request and extended sense set to Invalid Field in Parameter List.
When the Test bit is set to one and the Test Flag Number is set to valid non-zero
value, the drive will generate/clear a test informational exception condition. The
value of the Test bit returned by a Mode Sense command will remain at zero. The
test action is based on the Test Flag Number value:
1 to 64: This will set in the Log page the TapeAlert flag indicated by the Test Flag
Number. Once the TapeAlert flag is set it is processed normally based on the
DExcpt, MRIE, Interval Count and Report Count values.
-1 to -64: This will clear the TapeAlert flag indicated by the absolute value of the
Test Flag Number. Clearing the flag in this way is equivalent to performing the
specified corrective action for that flag, thus allowing a real information exception
condition to be set if the real error condition occurs for that flag.
32767 (0x7FFF): This will set in the Log page all of the TapeAlert flags that are
supported by the drive. Once the supported TapeAlert flags are set they are
processed normally based on the DExcpt, MRIE, Interval Count and Report Count
values.
MRIE (Default set to 3h):
This field indicates the method used by the drive to report informational exception
conditions. If the informational exception condition was generated by an event that
caused a real Check Condition to occur, then this real Check Condition will override
(i.e. be used instead of) the Check Condition defined in MRIE modes 1h to 5h. The
values defined for the MRIE field are:
0x0: No reporting of informational exception conditions. This method instructs
the tape drive to not report information exception conditions
0x1: Asynchronous Event Reporting. This method instructs the tape drive to
report information exception conditions by using the rules for asynchronous event
reporting as described in the SCSI-3 Architecture Model and the relevant protocol
standard. The sense key shall be set to RECOVERED ERROR and the additional
sense code shall indicate the cause of the information exception condition (which is
5D00h for a Tape Alert event).
0x2: Generate Unit Attention. This method instructs the tape drive to report
information exception conditions by returning a Check Condition status on the next
SCSI command (excluding Inquiry and Request Sense) after an informational
exception condition was detected. The sense key shall be set to UNIT ATTENTION
and the additional sense code shall indicate the cause of the information exception
condition (which is 5D00h for a Tape Alert event). The command that has the Check
Condition shall NOT be executed before the informational exception condition is
reported (and thus needs to be repeated).
0x3: Conditionally generate Recovered Error. This method instructs the tape
drive to report information exception conditions, if reporting of recovered errors is
allowed, by returning a Check Condition status on the next SCSI command
(excluding Inquiry and Request Sense) after an informational exception condition
was detected. The sense key shall be set to RECOVERED ERROR and the
additional sense code shall indicate the cause of the information exception condition