Tandberg Data SLR7-140 PROGRAMMER Manual page 33

Tandberg Data
2.3.4.1. Setting QFA-Mode
The MODE SELECT command is used to enter or leave the
QFA mode.
The Drive will be in non-QFA mode when the FDP bit in
the Medium Partition Parameter Page (Page Code 11h) is
set to zero. The Drive will be in QFA mode when the FDP
bit is set to one.
When going into QFA mode the FDP bit must be set to one
(the IDP bit must be set to zero). The Page Length field
must be set to 4Eh (to keep the page at a non-changing
length). The Maximum
ignored. The Additional
ignored (the Drive always partition the volume into two
partitions when FDP set to one). The SDP and the IDP
bits must be set to zero. The PSUM and Partition Units
fields are ignored.
to zero. The Medium Format Recognition field must be set
to 01h (the value returned by the MODE SENSE command).
The Partition Units field must be set to zero. The
Partition Size
drive (they can have any value).
When leaving QFA mode (when partitioning the volume into
a single partition) all fields have the values given
above. The only exception is that the FDP bit is set to
zero.
Setting or clearing the FDP bit is only legal when the
tape is positioned at BOT. Note also that a change in
partitioning (going from 1 to 2 partitions or the other
way around) leads to loss of all existing data (the
Drive runs an
partitions).
Since the Medium Partition Page(1) is not savable, the
Initiator is responsible
correct QFA mode is active whenever a new cartridge is
loaded.
When a QFA mode corresponding to the currently loaded
volume is in effect,
returned by the MODE SENSE command will indicate both
the number of partitions in effect and the size of those
partitions. In non-QFA mode the Additional Partitions
Defined field
partition). The
field returns the approximate size of the default (and
only) partition. In QFA mode the Additional Partitions
Defined field returns 01h (indicating a total of two
partitions). The first Partition Size Descriptor field
returns the approximate size of the data partition while
the second Partition Size Descriptor field indicates the
approximate size of the directory partition.
2.3.4.2. Changing Partition Using The LOCATE Command
The LOCATE command can be used to specify the active
partition. The Change Partition (CP) must be set to one
and the Partition
Partition) or 1 (Directory Partition). The Drive will
then move to the specified partition before the actual
block locate operation starts.
2-13 Tandberg SLR Product Line SCSI Functional Specifications
Additional
Partitions
The CLEAR and ADDP bits must be set
Descriptor fields
erase pass in
for
the Medium
returns 00h (indicating
very first Partition
field must
About Tape Streamers
Partitions field
Defined field
are ignored
each of the existing
making sure that
Partition Page(1)
a
Size Descriptor
be set to 0
is
is
by the
the
single
(Data