Data-Phase Command Components - Quantum DLT 8000 Product Manual

SCSI Commands
In contrast to the BUSY status condition, the DRIVE NOT READY Sense Key is returned as part of
the Sense data following a REQUEST SENSE command and indicates that a media access
command has been issued and the medium is not ready to be accessed. For example, the
medium is not installed, the medium has been unloaded, and the drive is currently initializing
the medium to prepare it for access.

5.1.4 DATA-Phase Command Components

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:
Field Name
Allocation Length
Parameter List Length
Transfer Length
Byte Transfer Length
The DATA OUT column in Table 5–5 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 after an item indicate the item's length in
bytes. In some cases, additional length information is communicated during the DATA
phase.
5-8
NOTE
Units Implied
Bytes of data the drive is allowed to send to the initiator
Bytes of data the initiator has available for the drive
Logical number of data blocks or data bytes the initiator wants
transferred or verified
Bytes of data the initiator wants transferred
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