HP C737990900 User Manual
Page 76
76
Commands
10-byte Header
The 10-byte Mode Parameter header has the following format:
Header Fields
7
6
5
4
3
2
1
0
0
(MSB)
Mode Data Length
1
(LSB)
2
Medium Type [00h]
3
WP
Buffered Mode [001b]
Speed (0)
4
Reserved (0)
5
6
(MSB)
Block Descriptor Length
7
(LSB)
Mode Data Length MODE SELECT:
Mode Data Length field must be zero.
MODE SENSE:
Mode Data Length field is set to the number of bytes of data available to
return excluding itself (in other words, the number of actual bytes available is
mode data length + 1 for 6-byte
MODE SENSE
or +2 for 10-byte
MODE
SENSE
).
Note:
The actual amount returned may be truncated to the allocation length
for the command.
Medium Type
00h The usual medium type when the drive is in normal tape drive mode.
WP
Write Protect. Ignored for
MODE SELECT
.
0
M
ODE SENSE
: The tape is write-enabled
1
M
ODE SENSE
: The tape is write-protected
Buffered Mode
0
The drive will not report
GOOD
status on
WRITE
and
WRITE FILEMARKS
commands until
all data (blocks and filemarks) has been successfully written to tape.
1
The drive will report
GOOD
status for
WRITE
and
WRITE FILEMARKS
commands as soon
as all the data or marks specified in the command have been transferred to the data
buffer. Data for multiple commands from different initiators may be buffered. This is
the default value.
Note:
It is strongly recommended that this field is set to 1, otherwise there will be
significant performance penalties. A method of flushing the buffer to tape without
changing logical position is available with the
WRITE FILEMARKS
command.