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Media Write Check
Parameter List Check
Reservation Check
This checks whether the media is write-protected. If it is,
reported with a sense key of
(write-protected).
For
,
LOG SELECT
MODE SELECT
associated data sent to the drive is in the form of parameter lists. These are
described under the command names in the next chapter. Checks are
performed to test the following:
Fixed and reserved fields have not been modified. Fixed fields are
indicated by a number in round brackets following the field name.
A field has been set to an invalid value.
The syntax of the page of parameters has been violated—for example,
where a particular value in one field imposes limitations on the valid range
for another field.
If a field has been set to an illegal value,
host with a sense key of
ILLEGAL REQUEST
(invalid field in parameter list).
The drive scans the data in the Command Description Block from "left" (bit 7)
to "right", and "down" (from byte 0 to byte n). It sets the field pointers to the
first bit of the first bad field encountered. If the bad field is contained in a
contiguous group of fixed fields, the pointers indicate the first bit of the first
field in the group, even though the error may be in a later field in the group.
With
Note
Mode Select
parameter list before acting on any parameters, so all the mode
parameters need to be correct before any of them are
implemented.
This checks to see if the drive has been reserved for use by a host, and if it has,
whether the host is the same host that sent the command being executed.
If the drive has been reserved for some other host then
status is reported.
See the
(page
RESERVE UNIT
and additional sense of 2700h
DATA PROTECT
and some diagnostic commands, the
CHECK CONDITION
and additional sense of 2600h
, the drive checks the integrity of the whole
141) and
(page
RELEASE UNIT
Commands—Introduction
is
CHECK CONDITION
is reported to the
RESERVATION CONFLICT
121) commands.
37
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