Abort handling – HP C737990900 User Manual
Page 16
16 Interface Implementation
default setting. The known base state is defined in the SCSI-3 specification and
includes the following:
■
The current I/O process is aborted.
■
Any queued I/O processes from other initiators are removed.
■
All reservations are cleared.
■
All mode values are reset to their defaults.
■
Synchronous/Wide negotiations are cleared
(SCSI drives only)
.
■
A
UNIT ATTENTION
condition is set.
■
Any buffered writes are flushed to tape.
■
The logical position is undefined.
The drive will be able to respond to
TEST UNIT READY
,
INQUIRY
,
REQUEST
SENSE
and
REPORT LUNS
within 250 ms of the reset line being released. The
first command other than these from any initiator will get a
CHECK
CONDITION
status with
UNIT ATTENTION
sense data for the reset. However,
other commands may not be processed until the internal state of the drive has
been reset. Any commands which cannot be processed will be accepted and
queued until the drive is ready to process them.
Hard Resets
The Reset button on the front panel and the ACI_RESET_L line on the
Automation Controller Interface are both connected to the Power-Up Reset
interrupt on the processor. The effect is equivalent to power-cycling the drive.
The contents of the tape and cartridge memory may not be consistent after the
action and any data in the drive buffer will be lost.
Abort Handling
If an abort condition is detected before a command phase completes, the bus
is set to bus free and the command is not executed.
If an abort condition is detected between the end of the command phase and
the start of the status phase, then the bus is set to bus free and the processing
below is carried out.
If an abort condition is detected during status phase, the bus is set to bus free.
If a command, other than
TEST UNIT READY
,
INQUIRY
and
REQUEST SENSE
, is
received after the abort but before the drive is ready to process the command,
the drive will disconnect and wait until the abort processing has completed
before executing the command. A
TEST UNIT READY
command will report with