Fujitsu MAU3036RC SERIES, Technical Manual

Page: 331 / 392

C141-C009 5-1
CHAPTER 5 Sense Data and Error Recovery
Methods
5.1 Sense Data
5.2 INIT Error Recovery Methods (Recommended)
5.3 Disk Drive Error Recovery Processing
In this chapter, the configuration and contents of sense data reported to the INIT
(initiator) when an error occurs, etc., key information for interpreting error states,
recommended procedures for error recovery processing that should be executed
by software in the INIT and error recovery processing executed internally by the
IDD are described.
5.1 Sense Data
When the IDD reports a CHECK CONDITION status, or in cases when some fatal
error is detected in connection with the SAS interface, and as a result, the command
that is currently being executed, or the commands in the stack are cleared, it generates
sense data for the INIT that issued that command. Sense data are returned to the
INIT at the same time as the status is sent in response to the command.
5.1.1 Sense data format
The IDD’s sense data is in the so-called “Expanded Sense Data” format. The
expanded sense data format supported by the IDD is shown in Table 5.1.
1) In the specifications, each device is permitted to define
whatever it chooses after byte 18 of the expanded sense data,
and the length and format differ for each device. The length of
expanded sense data is displayed in the sense data, so by
analyzing the sense data which it receives, the INIT can know
its effective length.