Element status data, Header, Element – Dell PowerVault TL2000 User Manual
Page 68: Status, Data, Sub-header, Descriptor), Page
DVCID:
If
the
DVCID
bit
is
set
the
media
changer
will
return
device
identifiers
for
the
Data
Transfer
element.
A
DVCID
bit
of
zero
specifies
that
the
device
shall
not
return
device
identifiers.
Allocation
Length:
This
field
specifies
the
number
of
bytes
that
the
initiator
has
allocated
for
returned
data.
Note
that
the
Read
Element
Status
command
can
be
issued
with
an
Allocation
Length
specified
as
8
bytes
(the
length
of
the
status
page
header)
to
determine
the
Allocation
Length
required
to
transfer
all
of
the
element
status
data
that
become
available
as
a
result
of
the
command.
Element
Status
Data
Data
returned
by
the
Read
Element
Status
command
is
described
below.
The
Element
Status
Data
consists
of
an
8-byte
Header
followed
by
one
or
more
status
pages
(for
each
element
type).
The
status
pages
are
made
up
of
an
8-byte
sub-header
and
one
or
more
element
descriptors
(one
for
each
element
address).
Header
The
data
returned
on
a
Read
Element
Status
command
always
starts
with
the
Header.
This
Header
reports
the
first
element
address,
the
number
of
elements,
and
the
byte
count
of
the
report.
Bit
7
6
5
4
3
2
1
0
Byte
0
-
1
First
Element
Address
Reported
2
-
3
Number
of
Elements
Available
4
Reserved
5
-
7
Byte
Count
of
Report
Available
Field
descriptions:
First
Element
Address
Reported:
This
field
indicates
the
element
address
of
the
element
with
the
smallest
element
address
found
to
meet
the
Read
Element
Status
command's
request.
Number
of
Elements
Available:
This
field
indicates
the
number
of
elements
found.
The
status
for
these
elements
is
returned
if
the
Allocation
Length
specified
in
the
Read
Element
Status
command's
CDB
was
sufficient.
Byte
Count
of
Report
Available:
This
field
indicates
the
number
of
available
element
status
bytes
that
meet
the
CDB
requirements.
This
value
does
not
adjust
to
match
the
Allocation
Length
field
of
the
CDB
and
does
not
include
the
8
byte
element
status
header.
Element
Status
Page
(Sub-header
and
Element
Descriptor)
The
Element
Status
Page
includes
an
8-byte
sub-header
and
one
or
more
element
descriptors.
The
sub-header
includes
the
element
type
code,
the
settings
for
PVolTag
and
AVolTag,
the
length
of
each
descriptor
block,
and
the
number
of
bytes
of
descriptor
information
that
follow
the
header
for
the
element.
Bit
7
6
5
4
3
2
1
0
Byte
0
Element
Type
Code
1
PvolTag
AvolTag
Reserved
2
-
3
Element
Descriptor
Length
3-54
TL2000
and
TL4000
SCSI
Reference