Tandberg Data
About Tape Streamers
2-5
Tandberg SLR Product Line SCSI Functional Specifications
When the IDP bit is zero, the second method is used. In
this case the FDP bit is used to select one or two fixed
size partitions. This method of using partitions is
often called “ Quick File Access” (QFA).
Regardless of which method is used, executing a MODE
SELECT command where the Medium Partition Page(1) is
included in the parameter list, some form of
partitioning will take place. This means that such a
MODE SELECT command is only accepted at the beginning of
partition 0 (BOP0).
The Partition Size Unit of Measure (PSUM) field defines
the unit of the Partition Size Descriptors. A value of
2 specifies the unit to be MBytes and a value of 3
specifies the unit to be GBytes. MODE SELECT will
ignore this field when the IDP bit is not set. MODE
SENSE will return 2 (MBytes) in this field when the
currently mounted volume has a capacity (uncompressed)
of 65535 MBytes or less. MODE SENSE will return 3
(GBbytes) in this field when the capacity is above 65535
MBytes. This boundary is introduced because 65535
(FFFFh) is the maximum value of the Partition Size
Descriptors.
The Partition Units field defines the unit of the
Partition Size Descriptors when the PSUM field is set to
3. The Partition Units must be set to 9 when the PSUM
field is set to 3 to indicate that GBytes (10
9
) is the
only supported unit.
The Maximum Additional Partitions field is ignored by
the MODE SELECT command. When the Medium Partition
Page(1) is returned by the MODE SENSE command this field
is used to indicate the maximum number of partitions (in
addition to the default partition) that the current
medium is able to hold.
The Additional Partitions Defined field is used to
specify the requested number of partitions (MODE SELECT)
or it shows the actual number of partitions (MODE
SENSE). The Partitions Size Descriptors is used to
specify the requested size of each partition (MODE
SELECT) or to show the current (estimated) size of each
partition (MODE SENSE).
Note that setting the IDP or FDP bits to one is only
allowed when the medium to be partitioned is a
SLRtape140 to SLRtape7 or SLR32, medium. In this case a
maximum of 24 partitions is allowed when using a
SLRtape140, SLRtape100, SLRtape75, SLRtape60 or
SLRtape40 medium. A maximum of 36 partitions is allowed
when using a SLRtape50, SLR32 or SLRtape24 medium. A
maximum of 3 partitions is allowed when using a SLRtape7
medium. (See also section 2.3.3 Using Initiator Defined
Partitions).
When using other medium types, partitioning can not be
used and only a single partition is available.
When partition sizes are quoted later on in this
section, all sizes are uncompressed sizes.
