Tandberg Data SLR7-140 PROGRAMMER, Руководство пользователя

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Tandberg Data About Tape Streamers
2-10 Tandberg SLR Product Line SCSI Functional Specifications
When the Medium Partition Page(1) is used to specify the
size of any partition, the Partition Size Descriptor
fields are used to specify a requested size. As the
actual partition size must match an integral number of
track set pairs, the Drive will round the value
requested up to the nearest number divisible by the
minimum partition size given by the loaded medium (see
table 2-2). As an example, if a partition is requested
to have a value of 450 MBytes, the Drive will round the
size up to 666 MBytes (333 * 2) when using an SLRtape24
medium, up to 694 MBytes when using an SLRtape50 medium
and up to 2916 MBytes when using an SLRtape140 medium.
If a partition is requested to have a size of 200
MBytes, the Drive will round the size up to 333, 444,
694 or 2916 Mbytes and so on. The Partition Size
Descriptors returned by the MODE SENSE command may be
used to read out the partition sizes after rounding has
taken place.
The number of Partition Size Descriptors must always
equal the Maximum Addition Partition plus one,
specifying the size of the default partition plus all
additional partitions. When the Additional Partitions
Defined is less than the Maximum Additional Partitions,
the last Partition Size Descriptors are set to zero. If
the Maximum Additional Partitions field has a value of
35 and the Additional Partitions Defined has a value of
n, then there must be n+1 non-zero Partition Size
Descriptors. These descriptors must be the first n+1
descriptors (the medium has been partitioned into n+1
partitions numbered 0 through n). The last 35-n Parti-
tion Size Descriptors are all set to zero. The size of
partition 0 (the default partition) must be greater than
zero.
The sum of all sizes requested by the non-zero Partition
Size Descriptors may be less than the total size on the
medium. In this case some capacity remains inaccessible.
Sometimes it may be desirable to have the last partition
cover the remainder of the medium. In this case the last
non-zero Partition Size Descriptor can be set to a value
of FFFFh.
If insufficient space exists on the medium for the
requested partition sizes or if multiple Partition Size
Descriptors are set to FFFFh, the Drive will return
CHECK CONDITION status.
When medium information has been read by the Drive, the
Medium Partition Page(1) returned by a MODE SENSE
command indicates the actual partitioning on the
currently mounted volume (the number and size of each
partition). When medium information has not yet been
read by the Drive, the Additional Partitions Defined and
the Partition Size Descriptor fields are undefined and
set to zeros. The SLR5 and DC9250 media have limited
medium information and the Additional Partitions Defined
and the Partition Size Descriptor fields are always
undefined and set to zeros for these media.
Note however that the partitions sizes returned by a
MODE SENSE command are estimated sizes. The sizes are
based on the calculated capacity for a given number of
pairs of track sets. The actual size achieved may differ
from the estimated size due to such factors as tape
length variations, the number of re-writes and amount of
filler data written by the Drive.