Reference Guide

Chapter 3 Transport Layer Implementation Details
Parallel SCSI
DLT-S4 Interface Reference Guide 10
Parallel SCSI 3
This section contains descriptions of each of the messages the drive
supports.
Parallel SCSI message-level errors are communicated by messages that
are defined specifically for that purpose (for example,
MESSAGE PARITY
ERROR
or MESSAGE REJECT). Message-level errors are also handled by
drive-managed retries (see Supported Messages
on page 11 for more
detailed message-handling information).
SCSI Bus Reset Condition 3 The DLT-S4 tape drive responds to bus reset conditions as follows:
• Within 250 milliseconds—and typically under 4 milliseconds—after a
bus reset, the drive responds to SCSI bus selections and returns the
appropriate normal responses. Tape motion commands are returned
with
CHECK CONDITION status, Sense Key of Not Ready, until the
drive makes the medium ready.
• The drive rewinds the tape to Beginning of Partition 0.
The DLT-S4 tape drive recognizes multiple bus resets in succession as
well as bus resets of arbitrarily long duration (power-on conditions). It
recovers within the time limits specified above following the last bus
reset.
Note: The DLT-S4 tape drive does not implement the hard reset
alternative for bus
RESET processing.