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MODE SELSECT
BOM
BOT
Partition 0
User
Device
System
EOD
Data
Area
Area
Area
BOM
BOT
Partition 0
User
Device
System
EOD DEV
Data
Area
Area
Area
BOM
BOT
Partition 0
User
Device
System
EOD
Data
Area
Area
Area
A tape does not require partitioning prior to use. On the first WRITE to a blank tape, the device creates the System,
Reference and Vendor areas before proceeding with the write. In order to reformat media from a two to a single, or
from a single to a two partition tape, the Host is required to use the Medium Partitions Parameter page.
PSUM: Partition Size Unit of Measured field defines the units in which the Partition Size value selects the partition
size, which in the case of this drive is Megabytes. Therefore, the drive returns 10b for a MODE SENSE and will only
accept this value for a MODE SELECT, otherwise a CHECK CONDITION status is returned with an ILLEGAL
REQUEST Sense Key set.
Medium Format Recognition: This field is only valid in response to the MODE SENSE command and is set to 03h
in order to indicate that the drive is capable of format and partition recognition. This is non-changeable field. It
accepts any values, and always returns 1.
Partition Sizes: This field allows the initiator to allocate the capacity for each partition. It will also allow the initiator to
reallocate the capacity of previously partitioned tapes.
The Partition Size specifies the capacity of all partitions in Megabytes (in the case of SDX-250V-see PSUM field
definition). The drive rounds the Partition Size to the next whole group value and then applies an algorithm which
allows for the writing of ECC-3 frames and for RAW error recovery so as to reserve sufficient physical space on the
media for the specified capacity. The minimum space allocated shall be 3050 frames.
SONY AIT-E Turbo drive SDX-250V series Ver.1.0
Single Partitioned Tape
Two Partitioned Tape
Partition 1
User
System
EOD
Data
Area
Area
Three Partitioned Tape
Partition 1
User
DEV
System
EOD DEV
Data
Area
Area
BOM = Beginning-of-Media (Physical)
BOT = Beginning-of-Tape (Logical)
EOM = End-of-Media (Physical)
EOP = End-of-Partition (Logical)
EOT = End-of-Tape (Logical)
Figure 6-2: Tape Partition Layout
Partition 2
User
System
EOD
Data
Area
Area
6.Command Specification
EOP/
EOM
EOT
EOP/
EOM
EOT
EOP/
EOM
EOT
6-37
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