Dynamic magnetic information storage or retrieval – Record transport with head stationary during transducing – Tape record
Reexamination Certificate
2001-01-19
2004-06-22
Letscher, George J. (Department: 2653)
Dynamic magnetic information storage or retrieval
Record transport with head stationary during transducing
Tape record
Reexamination Certificate
active
06754038
ABSTRACT:
The present invention relates to a library apparatus that reads and writes data from and to a magnetic cartridge tape used as the recording medium, and particularly to a library apparatus adapted to correct the alignment of a leader block attached to the leading end of a recording tape, so that the tape can be pulled out of its cartridge by the leader block.
BACKGROUND OF THE INVENTION
Some computer systems include at least one library apparatus which stores a plurality of magnetic tape cartridges in the racks of its cell units. In this type of library apparatus, after the desired cartridge is ejected from a rack in response to a command from the computer and is set in a magnetic tape apparatus, backup data are written to or read from the cartridge.
FIG. 21
is a schematic of the structure of a conventional library apparatus. In this drawing, auto cartridge loader (ACL)
10
includes a cell unit (not shown in
FIG. 21
) for storing a plurality of cartridges
300
shown in
FIGS. 22 and 23
, and an accessor mechanism (ACC) (not shown in
FIG. 21
) that automatically transfers a cartridge
300
to the cell unit or a magnetic tape unit (MTU)
20
, to be described later, in response to commands from the computer (not shown).
The cell unit described above is constructed from a plurality of racks called cells. The cartridges
300
are stored in these cells. The ACC ejects a cartridge
300
from the desired cell in the cell unit in response to commands from the computer and automatically transfers it to the MTU
20
. In addition, the ACC ejects a cartridge
300
from the MTU
20
and automatically transfers it to a cell in the cell unit.
FIG. 22
is a perspective view showing the structure of the cartridge
300
in an upright state.
FIG. 23
is a perspective view showing the structure when the cartridge
300
has been turned over. A cartridge case
301
of the cartridge
300
has a generally box shape and accommodates a tape
302
, which is the magnetic recording medium, wound around a tape reel
304
. Data is written to or read from this tape
302
by the MTU
20
.
A cartridge top
301
c
of the cartridge case
301
is formed from a transparent resin. Thus, the tape
302
wound around the tape reel
304
can be checked from the outside through the cartridge top
301
c
. A leader block latch
301
b
is an opening formed on the left side of a side surface
301
a
and functions as a leader port to pull out the tape
302
from the cartridge
300
and to latch or hold a leader block
303
to the cartridge case
301
.
The leader block
303
is attached to a tip
302
a
of the tape
302
and is the member that engages a threader pin
234
(shown in
FIG. 24A
) when the tape
302
is pulled out of the cartridge
300
and when the pulled out tape
302
is stored back in the cartridge
300
. The tape tip
302
a
is attached and fixed to a tape tip mount
303
a
. The threader pin latch
303
b
is formed to have a nearly hook-shaped cross-section to engage the threader pin
234
.
In the above structure, in response to commands from the computer, the ACC of the ACL
10
ejects a cartridge
300
from the desired cell in the cell unit and automatically transfers it to a transfer position on the MTU
20
. The threader pin
234
is positioned at the initial position in the MTU
20
as shown in FIG.
25
A. Then the MTU
20
loads the cartridge
300
from the transfer position to a read/write position, where the threader pin latch
303
b
of the leader block
303
engages the threader pin
234
as shown in FIG.
25
A. Next, as shown in
FIG. 25B
, under the control of the MTU
20
, the tape reel
304
is rotated forward by a motor (not shown), and the tape
302
is pulled out of the cartridge
300
by the motion of the threader pin
234
in the X+ direction. Then the MTU
20
reads from or writes to the tape
302
.
When the reading or the writing process on the tape
302
is finished, the tape reel
304
is rotated backwards by a motor (not shown), and the tape
302
is wound back inside the cartridge
300
by the motion of the threader pin
234
in the opposite direction to the X+ direction.
Next, the MTU
20
unloads the cartridge
300
from the read/write position to the transfer position. The ACC in the ACL
10
ejects the cartridge
300
from the MTU
20
and automatically transfers it to the desired cell of the cell unit in the ACL
10
. Thus, the cartridge
300
is stored in a cell.
At times, the leader block
303
separates from the tape
302
in a conventional library apparatus because of pressure applied from the outside or deterioration over time. Usually, the leader block
303
can be reattached to the tape
302
by using a special tool. Often, however, the leader block
303
may be attached improperly at an incline with respect to the tape
302
as shown in FIG.
24
A.
Consequently, the leader block
303
could slip and separate from the threader pin
234
while the tape
302
is being pulled out of the cartridge
300
by the threader pin
234
. Typically, when this occurs, after the tape
302
is temporarily stored back in the cartridge
300
and the cartridge is unloaded from the MTU
20
, then the cartridge
300
is reloaded and a retry of the read or write process is performed. That is, when a leader block slip occurs, the tape reel
304
is rotated to store the tape
302
back in the cartridge
300
. As shown in
FIG. 24C
, however, the leader block
303
does not fully latch to the leader block latch
301
b
(best shown in
FIG. 22
) because the leader block is mounted at an incline with respect to the tape
302
. Next, the threader pin
234
moves towards the leader block
303
in the X− direction. As shown in
FIG. 24D
, the threader pin
234
does not properly engage the leader block
303
because the leader block has not engaged the leader block latch
301
b
properly. As a result, the threader pin
234
and its supporting parts could become damaged when the threader pin collides with the leader block
303
, requiring not only the threader pin
234
, but other related parts to be replaced, which increases maintenance costs.
In the properly attached state, if a retry is performed with the leader block
303
attached to the tape
302
, the leader block will be fully latched to the leader block latch
301
b
. Therefore, the threader pin
234
will not collide with the leader block
303
.
Another problem associated with a conventional library apparatus is that the driving force of the motor (not shown) that rotates the tape reel
304
backwards becomes weaker over time due to deterioration. As a result, the leader block
303
incompletely latches to the leader block latch
301
b
when the tape
302
is wound in the cartridge
300
. In this case, since the leader block
303
of the cartridge
300
is stored in a cell in an incompletely latched state, the leader block
303
must be pushed into the leader block latch
301
b
, which is a serious problem in maintenance management.
Accordingly, one object of this invention is to provide improved library apparatus which prevents a threader pin from colliding with and damaging the leader block of a tape cartridge.
Another object of this invention is to provide improved library apparatus having a magnetic tape unit which holds a cartridge in a position where the threader pin is prevented from colliding with and damaging the leader block of the cartridge.
Yet another object of this invention is to provide improved library apparatus having a pressing device which is adapted to push the leader block into a latch provided on the cartridge.
SUMMARY OF THE INVENTION
In keeping with one aspect of this invention, a library apparatus is adapted to write to and read from a plurality of cartridges each housing a tape wound around a reel. The tape has a leader block attached to a tip thereof for pulling the tape out of its cartridge and adapted to be seated in a leader block latch provided on the cartridge. The apparatus includes a cell unit having a plurality of cells for storing the tape cartridges, a threader unit for writing data t
Akiyama Hitomi
Akiyama Yoshiki
Blouin Mark S
Fujitsu Limited
Greer Burns & Crain Ltd.
Letscher George J.
LandOfFree
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