User's Guide

Chapter 3 Emulated DLT7000 SCSI Commands
Overview of Command and Status Processing
Quantum DX-Series Software Interface Guide 115
DATA-Phase
Command
Components
3
Many of the SCSI commands cause data to be transferred between the
initiator and the drive. The content and characteristics of this data are
command-dependent. Table 5–5 lists the information transmitted for all
of the commands.
The "Length in CDB" column of Table 5–5 identifies the Command
Descriptor Block field used by the drive to determine how much
command-related data are to be transferred. The units (bytes or logical
blocks) for the different Length fields are implied by the Length Field
Name as follows:
The DATA OUT column in table 76 lists the information passed to the
drive by the initiator as part of the command. The DATA IN column lists
the information sent to the initiator by the drive. Numbers in parentheses
18h RESERVATION
CONFLICT
Another initiator has reserved the drive when it has
been reserved for another initiator with a RESERVE
UNIT command (this status is never returned for
INQUIRY or REQUEST SENSE commands).
28h QUEUE FULL The drive cannot service the command at the moment,
and its Command Descriptor Block has been discarded.
(Returned for a tagged command when all of the drive's
internal command buffers are in use, for instance.)
Field Name Units Implied
Allocation Length Bytes of data the drive is allowed
to send to the initiator
Parameter List Length Bytes of data the initiator has
available for the drive
Transfer Length Logical number of data blocks or
data bytes the initiator wants
transferred or verified
Byte Transfer Length Bytes of data the initiator wants
transferred
Status Code Definition Meaning