Dell PowerVault TL4000 SCSI Reference Guide - Page 98

WRITE, BUFFER, Write

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WRITE BUFFER (3Bh) Write Buffer is used with Read Buffer as a diagnostic function for testing the device data buffer, DMA engine, SCSI bus interface hardware, and SCSI bus integrity. Additional modes are provided for downloading and saving micro code and updating Vendor Unique settings. Bit 7 Byte 0 1 2 3 (MSB) 4 5 6 (MSB) 7 8 9 6 LUN 5 4 3 2 1 Operation Code (3Bh) Reserved Buffer ID Mode Buffer offset Parameter list length Control 0 (LSB) (LSB) Field descriptions: Mode: The Mode field is used to select the mode of operation. The media changer supports the following values within this field. 0010b 0100b 0101b 1010b Data Download microcode Download microcode and save Echo buffer If any non supported value is set, the media changer terminates the command with a Check Condition status. The sense key will be set to ILLEGAL REQUEST and the sense data to INVALID FIELD IN CDB. Buffer ID: When the Mode is set to Download micro code or Download micro code and save, the Buffer ID should be set to zero. When the mode is set to Vendor Unique operation, the Buffer ID indicates the requested page to update. If the value of the Buffer ID is not supported by the specified Mode the command is rejected. The target detects and rejects commands that would overrun the buffer. Buffer Offset: The Buffer Offset is required for the Download micro code (and save) modes and optional for the Vendor Unique and Data modes. In all other modes the Buffer Offset must be set to zero. Write Data Mode With this mode, SCSI bus integrity can be tested in conjunction with the READ BUFFER command. The host can by means of this mode send up to 256 bytes to the media changer. This data can be retrieved by means of the READ BUFFER command. The Buffer Offset specifies the offset within the buffer. Potential buffer overruns are detected and will result into a Check Condition the sense key will be set to ILLEGAL REQUEST and the additional sense data to INVALID FIELD IN CDB. 3-84 TL2000 and TL4000 SCSI Reference

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WRITE
BUFFER
(3Bh)
Write
Buffer
is
used
with
Read
Buffer
as
a
diagnostic
function
for
testing
the
device
data
buffer,
DMA
engine,
SCSI
bus
interface
hardware,
and
SCSI
bus
integrity.
Additional
modes
are
provided
for
downloading
and
saving
micro
code
and
updating
Vendor
Unique
settings.
Bit
7
6
5
4
3
2
1
0
Byte
0
Operation
Code
(3Bh)
1
LUN
Reserved
Mode
2
Buffer
ID
3
(MSB)
4
Buffer
offset
5
(LSB)
6
(MSB)
7
Parameter
list
length
8
(LSB)
9
Control
Field
descriptions:
Mode:
The
Mode
field
is
used
to
select
the
mode
of
operation.
The
media
changer
supports
the
following
values
within
this
field.
0010b
Data
0100b
Download
microcode
0101b
Download
microcode
and
save
1010b
Echo
buffer
If
any
non
supported
value
is
set,
the
media
changer
terminates
the
command
with
a
Check
Condition
status.
The
sense
key
will
be
set
to
ILLEGAL
REQUEST
and
the
sense
data
to
INVALID
FIELD
IN
CDB.
Buffer
ID:
When
the
Mode
is
set
to
Download
micro
code
or
Download
micro
code
and
save,
the
Buffer
ID
should
be
set
to
zero.
When
the
mode
is
set
to
Vendor
Unique
operation,
the
Buffer
ID
indicates
the
requested
page
to
update.
If
the
value
of
the
Buffer
ID
is
not
supported
by
the
specified
Mode
the
command
is
rejected.
The
target
detects
and
rejects
commands
that
would
overrun
the
buffer.
Buffer
Offset:
The
Buffer
Offset
is
required
for
the
Download
micro
code
(and
save)
modes
and
optional
for
the
Vendor
Unique
and
Data
modes.
In
all
other
modes
the
Buffer
Offset
must
be
set
to
zero.
Write
Data
Mode
With
this
mode,
SCSI
bus
integrity
can
be
tested
in
conjunction
with
the
READ
BUFFER
command.
The
host
can
by
means
of
this
mode
send
up
to
256
bytes
to
the
media
changer.
This
data
can
be
retrieved
by
means
of
the
READ
BUFFER
command.
The
Buffer
Offset
specifies
the
offset
within
the
buffer.
Potential
buffer
overruns
are
detected
and
will
result
into
a
Check
Condition
the
sense
key
will
be
set
to
ILLEGAL
REQUEST
and
the
additional
sense
data
to
INVALID
FIELD
IN
CDB.
3-84
TL2000
and
TL4000
SCSI
Reference