U.S. patent application number 16/286660 was filed with the patent office on 2019-08-29 for tape drive temperature control for media dimensional stability.
The applicant listed for this patent is International Business Machines Corporation. Invention is credited to Nhan X. Bui, David H.F. Harper, Randy C. Inch, Kevin B. Judd, Mark A. Lantz.
Application Number | 20190267035 16/286660 |
Document ID | / |
Family ID | 66996636 |
Filed Date | 2019-08-29 |
United States Patent
Application |
20190267035 |
Kind Code |
A1 |
Bui; Nhan X. ; et
al. |
August 29, 2019 |
TAPE DRIVE TEMPERATURE CONTROL FOR MEDIA DIMENSIONAL STABILITY
Abstract
A determination is made whether read/write is enabled within the
tape drive storage unit. In response to determining that read/write
is enabled, a determination is made whether an absolute value of a
channel offset exceeds a threshold value. In response to
determining that the absolute value of the channel offset exceeds a
threshold value, a direction of travel of the tape media is
determined. In response to determining that the direction of travel
of the tape media is a forward direction, a determination is made
whether the channel offset is positive. In response to determining
that the channel offset is positive, a left cooling device within
the tape drive storage unit is powered on. The left cooling device
lowers the temperature of a left guide roller and the tape media
coming off a left tape storage reel prior to the media passing by a
read/write head.
Inventors: |
Bui; Nhan X.; (Tucson,
AZ) ; Judd; Kevin B.; (Vail, AZ) ; Inch; Randy
C.; (Tuscon, AZ) ; Lantz; Mark A.; (Thalwil,
CH) ; Harper; David H.F.; (Vail, AZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
International Business Machines Corporation |
Armonk |
NY |
US |
|
|
Family ID: |
66996636 |
Appl. No.: |
16/286660 |
Filed: |
February 27, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15905873 |
Feb 27, 2018 |
10332554 |
|
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16286660 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G11B 33/1406 20130101;
G11B 5/00813 20130101; G11B 15/60 20130101 |
International
Class: |
G11B 15/60 20060101
G11B015/60; G11B 5/008 20060101 G11B005/008 |
Claims
1. A computer system comprising: one or more computer processors; a
tape drive storage unit connected to the one or more computer
processors, the tape drive storage unit comprising a tape media,
first cooling device; a first guide roller, a first tape storage
reel and a read/write head within the tape drive storage unit; a
computer-readable storage media coupled to the one or more computer
processors, wherein the computer readable storage media contains
program instructions executing a computer-implemented method
comprising the steps of: determining whether read/write is enabled
within the tape drive storage unit; determining whether an absolute
value of a channel offset exceeds a threshold value; determining a
direction of travel of the tape media; determining that the
direction of travel of the tape media within the tape drive storage
unit is a forward direction and whether the channel offset is
positive; responsive to determining that the channel offset is
positive, powering on the first cooling device of the tape drive
storage unit; lowering a temperature of the first guide roller and
tape media coming off the first tape storage reel prior to the tape
media passing by the read/write head.
2. The computer system of claim 1, further comprising: a first
heating device within the tape drive storage unit, and responsive
to determining that the channel offset is not positive, the first
heating device increases the temperature of the first guide roller
and the tape media coming off the first tape storage reel prior to
the tape media passing by the read/write head.
3. The computer system of claim 1, wherein the tape drive storage
unit further comprises a second cooling device, a second guide
roller and a second tape storage reel; responsive to determining
that the direction of travel of the tape media within the tape
drive storage unit is not a forward direction, further determining,
whether a channel offset is positive; responsive to determining
that the channel offset is positive, powering on the second cooling
device; and lowering a temperature of the second guide roller and
the tape media coming off the second tape storage reel prior to the
tape media passing by the read/write head of the tape drive storage
unit.
4. The computer system of claim 3, further comprising: a second
heating device within the tape drive storage unit; responsive to
determining that the channel offset is not positive, powering on,
the second heating device within the tape drive storage unit;
increasing the temperature of the second guide roller and the tape
media coming off the second tape storage reel prior to the tape
media passing by the read/write head within the tape drive storage
unit.
5. The computer system of claim 1, wherein the channel offset is a
difference between a first span and a second span, where the first
span is a first distance between read/write head servo reader
elements and the second span is a second distance between servo
patterns on the tape media.
6. The computer system of claim 2, wherein the first cooling device
and the first heating device maintain tape dimensional stability to
prevent read/write errors.
7. The computer system of claim 1, further comprising: responsive
to determining that the read/write is not enabled within the tap
drive storage unit or the read/write is enabled within the tape
drive storage unit and the absolute value of the channel offset
does not exceed the threshold value, powering off any cooling
device or heating device that is powered on.
8. The computer system of claim 1, further comprising a controller,
wherein the controller comprises the one or more computer
processors.
9. The computer system of claim 8, wherein the controller sends
read/write instructions to the read/write head.
10. The computer system of claim 2, wherein the first cooling
device and the first heating device are Perltier thermoelectric
devices.
11. A computer system comprising: a controller comprising one or
more processors; a first tape storage reel connected to the
controller a second tape storage reel connected to the controller;
a read/write head, located between the first tape storage reel and
the second tape storage reel; a tape attached to the first tape
storage reel on an end of the tape and the tape attached to the
second tape storage reel on an opposing end of the tape; a tape
transport mechanism configured to move the tape along a tape path
between the first tape storage reel and the second tape storage
reel; a first cooling device attached to and placed in intimate
contact with a first portion of the tape transport mechanism; and a
computer-readable storage media coupled to the controller, wherein
the computer readable storage media contains program instructions
executing a computer-implemented method comprising the steps of:
determining whether read/write is enabled; determining whether an
absolute value of a channel offset exceeds a threshold value;
determining a direction of travel of the tape; determining that the
direction of travel of the tape is a forward direction and whether
the channel offset is positive; responsive to determining that the
channel offset is positive, powering on the first cooling device
and lowering a temperature of the tape transport mechanism and tape
coming off the first tape storage reel prior to the tape passing by
the read/write head.
12. The computer system of claim 11 further comprising: a first
heating device attached to and in intimate contact with a second
portion of the tape transport mechanism; and responsive to
determining that the channel offset is not positive, powering on
the first heating device and increasing the temperature of the tape
transport mechanism and the tape coming off the first tape storage
reel prior to the tape passing by a read/write head.
13. The computer system of claim 11, further comprising: a second
cooling device attached to and in intimate contact with a third
portion of the tape transport mechanism; responsive to determining
that the direction of travel of the tape media within the tape
drive storage unit is not a forward direction, further determining,
whether a channel offset is positive; responsive to determining
that the channel offset is positive, powering on the second cooling
device and lowering a temperature of the tape transport mechanism
and the tape coming off the second tape storage reel prior to the
tape media passing by the read/write head.
14. The computer system of claim 13, further comprising: a second
heating device attached to and in intimate contact with a fourth
portion of the tape transport mechanism; responsive to determining
that the channel offset is not positive, powering on, the second
heating device and increasing the temperature of the tape transport
mechanism and the tape coming off the second tape storage reel
prior to the tape passing by the read/write head.
15. The computer system of claim 11, wherein the channel offset is
a difference between a first span and a second span, where the
first span is a first distance between read/write head servo reader
elements and the second span is a second distance between servo
patterns on the tape media.
16. The computer system of claim 12, wherein the first cooling
device and the first heating device maintain tape dimensional
stability to prevent read/write errors.
17. The computer system of claim 11, wherein the controller sends
read/write instructions to the read/write head.
18. The computer system of claim 12, wherein the tape transport
mechanism comprises a first guide roller and a second guide roller;
the first guide roller and the second guide roller each include a
main cylinder constrained to a stationary shaft by two roller
bearing sub-assemblies which allow free rotation of the main
cylinder around the stationary shaft; the first guide roller is
positioned in the tape path between the first tape storage reel and
the read/write head; and the second guide roller is positioned in
the tape path between the second tape storage reel and the
read/write head.
19. The computer system of claim 18, wherein: the first cooling
device is attached to and in intimate contact with a first portion
of a side of the main cylinder of the first guide roller; and the
first heating device is attached to and in intimate contact with a
second portion of the side of the main cylinder of the first guide
roller, wherein the first portion and the second portion cover an
entire side of the main cylinder of the first guide roller.
20. The computer system of claim 12, where the first cooling device
and the first heating device are Perltier thermoelectric devices.
Description
BACKGROUND
[0001] The present invention relates generally to the field of
magnetic tape data storage, and more particularly to controlling
the temperature within a tape drive to maintain the dimensional
stability of the media within the tape drive.
[0002] Magnetic tape data storage (e.g., an automated tape library)
is a system for storing digital information on a magnetic tape
media using digital recording. Modern magnetic tape is most
commonly packaged in cartridges and cassettes; however, open reels
are also used to hold the tape media. The tape drive is the device
that performs writing or reading of data on the magnetic tape.
Autoloaders automate cartridge handling and provide increased speed
for accessing data stored on the tape media.
SUMMARY OF THE INVENTION
[0003] Embodiments of the present invention includes a system and
method for controlling the temperature within a tape drive storage
unit to maintain the dimensional stability of the media within the
tape drive. In one embodiment, the system is comprised of the
following: a left tape storage reel located on a left side of the
apparatus; a right tape storage reel located on a right side of the
apparatus; a tape attached to the left tape storage reel on an end
of the tape and the tape also attached to the right tape storage
reel on an opposing end of the tape, wherein the tape is magnetic;
a tape transport mechanism, wherein the tape transport mechanism
moves the tape along a tape path between the left tape storage reel
and the right tape storage reel; a read/write head located between
the left tape storage reel and the right tape storage reel; a left
cooling device attached to and in intimate contact with a first
portion of the tape transport mechanism; a right cooling device
attached to and in intimate contact with a second portion of the
tape transport mechanism; a left heating device attached to and in
intimate contact with a third portion of the tape transport
mechanism; a right heating device attached to and in intimate
contact with a fourth portion of the tape transport mechanism; and
a controller.
[0004] Additional embodiments of the present invention include a
system and method for controlling the temperature within a tape
drive storage unit to maintain the dimensional stability of the
media within the tape drive. In one embodiment, a determination is
made whether read/write is enabled within the tape drive storage
unit. In response to determining that read/write is enabled, a
determination is made whether an absolute value of a channel offset
exceeds a threshold value. In response to determining that the
absolute value of the channel offset exceeds a threshold value, a
direction of travel of the tape media is determined. In response to
determining that the direction of travel of the tape media is a
forward direction, a determination is made whether the channel
offset is positive. In response to determining that the channel
offset is positive, a left cooling device within the tape drive
storage unit is powered on. The left cooling device lowers the
temperature of a left guide roller and the tape media coming off a
left tape storage reel prior to the media passing by a read/write
head.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 depicts a schematic of an example tape storage unit
with heater/cooler pairs on each guide roller, in accordance with
an embodiment of the present invention;
[0006] FIG. 2 depicts a schematic of an example tape storage unit
with independent heaters and coolers, in accordance with an
embodiment of the present invention;
[0007] FIG. 3 depicts a flowchart of a program for controlling the
temperature within a tape drive to maintain the dimensional
stability of the media within the tape drive, in accordance with an
embodiment of the present invention; and
[0008] FIG. 4 depicts a block diagram of components of a computing
environment, in accordance with an embodiment of the present
invention.
DETAILED DESCRIPTION
[0009] Embodiments of the present invention provide for controlling
the temperature within a tape drive to maintain the dimensional
stability of the media within the tape drive. Temperature
fluctuations within the tape drive can result in tape dimensional
stability (TDS) issues. If the temperature is too hot within the
tape drive, the media (i.e., tape) can increase in size due to
thermal expansion. If the temperature is too cold within the tape
drive, the media can decrease in size due to thermal contraction.
In either instance, read/write errors can occur.
[0010] Embodiments of the present invention disclose an approach
for controlling the temperature within a tape drive to maintain the
dimensional stability of the media within the tape drive. In an
embodiment, thermoelectric devices (such as Peltier devices) are
placed inside the tape drive and are used to heat or cool the tape
media and guide rollers, which helps to control the expansion or
contraction of the media to maintain TDS.
[0011] References in the specification to "one embodiment", "an
embodiment", "an example embodiment", etc., indicate that the
embodiment described may include a particular feature, structure,
or characteristic. Moreover, such phrases are not necessarily
referring to the same embodiment. Further, when a particular
feature, structure, or characteristic is described in connection
with an embodiment, it is submitted that it is within the knowledge
of one skilled in the art to affect such feature, structure, or
characteristic in connection with other embodiments whether or not
explicitly described.
[0012] For purposes of the description hereinafter, the terms
"upper", "right", "left", "vertical", "horizontal", "top",
"bottom", and derivatives thereof shall relate to the disclosed
structures and methods, as oriented in the drawing Figures. The
terms "overlaying", "atop", "positioned on", or "positioned atop"
mean that a first element, such as a first structure, is present on
a second element, such as a second structure, wherein intervening
elements, such as an interface structure may be present between the
first element and the second element. The term "direct contact"
means that a first element, such as a first structure, and a second
element, such as a second structure, are connected without any
intermediary conducting, insulating or semiconductor layers at the
interface of the two elements.
[0013] As referred to herein, certain components in this
specification are substantially similar with the exception of a
"right side" versus "left side" position and arrangement within the
tape drive (e.g., in FIG. 1, left tape storage reel 102A and right
tape storage reel 102B). In those situations where components are
substantially similar, only one of the substantially similar
components will be described in detail (e.g., only left tape
storage reel 102A will be described in detail).
[0014] The present invention will now be described in detail with
reference to the Figures.
[0015] FIG. 1 is a schematic of an example tape storage unit with
right and left guide rollers, generally designated 100, in
accordance with one embodiment of the present invention. FIG. 1
provides only an illustration of one implementation and does not
imply any limitations with regard to the different embodiments that
may be implemented. Many modifications to the depicted embodiment
may be made by those skilled in the art without departing from the
scope of the invention as recited by the claims.
[0016] In an embodiment, tape storage unit 100 includes left tape
storage reel 102A, right tape storage reel 102B, read/write head
104, tape 106, left guide roller 112A, right guide roller 112B,
left cooler 114A, right cooler 114B, left heater 116A, right heater
116B, controller 118, and temperature program 120.
[0017] In an embodiment, left tape storage reel 102A is an open
reel made of a plastic, or a similar material, used to either
collect or dispense the tape media as the tape media travels across
read/write head 104 within tape storage unit 100. In an embodiment,
left tape storage reel 102A is ninety-seven plus or minus one
millimeter in diameter. In another embodiment, left tape storage
reel 102A can be any diameter. According to embodiments of the
present invention, left tape storage reel 102A may be contained
within a cartridge or a cassette instead of being an open reel. In
an embodiment, right tape storage reel 102B is substantially
similar to left tape storage reel 102A.
[0018] In an embodiment, read/write head 104 is a type of
transducer in tape storage unit 100 used to convert electrical
signals to magnetic fluctuations and vice versa for writing and
reading, respectively, data to and/or from tape 106. In an
embodiment, read/write head 104 includes a toroidal core with a
small air gap. In the embodiment, a coil of wire is wound around
the toroidal core which is made of a magnetically permeable metal.
Passing an electrical signal through the coil of wire results in a
changing magnetic field which flows through tape 106 when passing
adjacent to read/write head 104. In this manner, read/write head
104 is able to change the electrical polarity of the bits on tape
106 resulting in data records being stored to tape 106 as a series
of zeroes and ones for digital data. Reversing the process induces
an electrical current across the small air gap allowing read/write
head 104 to read (i.e., retrieve) data from tape 106. In other
embodiments, data may be read using a shielded magnetoresistive
sensor such as an anisotropic magnetoresistive (AMR) sensor, a
giant magnetoresistive (GMR) sensor, and a tunneling
magnetoresistive (TMR) sensor.
[0019] In an embodiment, tape 106 is the media within tape storage
unit 100 that data is written to or read from via read/write head
104. In an embodiment, tape 106 includes a plastic film base
material (e.g., polyethylene naphthalate) with a thin, magnetizable
coating on the surface (e.g., metal particulate, barium ferrite).
In the embodiment, tape 106 includes four data bands, varying
numbers of wraps per band, and varying numbers of tracks
(read/write elements) per wrap. The number of wraps/band and
tracks/wrap determine the total number of tracks on tape 106
available for data storage.
[0020] In an embodiment, forward direction 108A is a direction of
travel for tape 106 when tape 106 is coming off of left tape
storage reel 102A and being wound onto right tape storage reel
102B. In the embodiment, when tape 106 is traveling in forward
direction 108A, tape 106 moves across read/write head 104 from the
left to the right.
[0021] In an embodiment, backward direction 108B is the opposite
direction of travel of tape 106 from forward direction 108A.
[0022] In an embodiment, left guide roller 112A is a sub-assembly
component of the tape transport mechanism within tape storage unit
100 that guides tape 106 as tape 106 moves between left tape
storage reel 102A and read/write head 104. According to an
embodiment of the present invention, left guide roller 112A is a
sub-assembly that consists of a main cylinder constrained to a
stationary shaft by two roller bearing sub-assemblies which allow
free rotation of the main cylinder around the stationary shaft. In
an embodiment, left guide roller 112A changes the direction of
travel of tape 106 by ninety plus or minus two degrees. According
to an embodiment of the present invention, left guide roller 112A
is made from stainless steel. According to another embodiment, left
guide roller 112A is made from a non-stainless steel with a
coating. In an embodiment, right guide roller 112B is substantially
similar to left guide roller 112A with the exception that right
guide roller 112B guides tape 106 as tape 106 moves between right
tape storage reel 102B and read/write head 104.
[0023] In an embodiment, left cooler 114A is a thermoelectric
cooling device (e.g., a Peltier cooler) used to lower the
temperature of left guide roller 112A and tape 106 within tape
storage unit 100. In an embodiment, left cooler 114A is attached to
and in intimate contact with (i.e., covers) fifty plus or minus two
percent of left guide roller 112A. In another embodiment, left
cooler 114A is attached to and in intimate contact with any
percentage of left guide roller 112A. According to embodiments of
the present invention, left cooler 114A uses the Peltier effect to
create a heat flux between the junction of two different types of
materials. Left cooler 114A is a solid-state active heat pump which
transfers heat from one side of a device to the other, with
consumption of electrical energy, depending on the direction of the
current. The advantages of Peltier cooling are a lack of moving
parts or circulating liquid, very long life, invulnerability to
leaks, small size, and flexible shape. The disadvantages of Peltier
cooling are high cost and poor power efficiency. In an embodiment,
right cooler 114B is substantially similar to left cooler 114A with
the exception that right cooler 114B is attached to and in intimate
contact with fifty plus or minus two percent of right guide roller
112B.
[0024] In an embodiment, left heater 116A is a thermoelectric
heating device (e.g., a Peltier heater) used to increase (i.e.,
raise) the temperature of left guide roller 112A and tape 106
within tape storage unit 100. In an embodiment, left heater 116A is
attached to and in intimate contact with (i.e., covers) fifty plus
or minus two percent of left guide roller 112A. In another
embodiment, left heater 116A is attached to and in intimate contact
with any percentage of left guide roller 112A. According to
embodiments of the present invention, left heater 116A uses the
Peltier effect to create a heat flux between the junction of two
different types of materials. In an embodiment, left heater 116A is
a solid-state active heat pump which transfers heat from one side
of a device to the other, with consumption of electrical energy,
depending on the direction of the current. The advantages of
Peltier heating are a lack of moving parts or circulating liquid,
very long life, invulnerability to leaks, small size, and flexible
shape. The disadvantages of Peltier heating are high cost and poor
power efficiency. In an embodiment, right heater 116B is
substantially similar to left heater 116A with the exception that
right heater 116B is attached to and in intimate contact with fifty
plus or minus two percent of right guide roller 112B.
[0025] In an embodiment, thermoelectric devices left cooler 114A
and left heater 116A are in opposite orientation compared to one
another so that left cooler 114A lowers the temperature of left
guide roller 112A and tape 106 while left heater 116A increases the
temperature of left guide roller 112A and tape 106. In the
embodiment, thermoelectric devices right cooler 114B and right
heater 116B are in opposite orientation compared to one another so
that right cooler 114B lowers the temperature of right guide roller
112B and tape 106 while right heater 116B increases the temperature
of right guide roller 112B and tape 106. In another embodiment,
left cooler 114A, left heater 116A, right cooler 114B, and right
heater 116B are located in any orientation and/or position with
respect to one another such that the respective guide rollers and
tape media can be heated and/or cooled to maintain tape dimensional
stability. According to an embodiment of the present invention,
left cooler 114A and left heater 116A cover an entire side of left
guide roller 112A. Also according to the embodiment, right cooler
114B and right heater 116B cover an entire side of right guide
roller 112B.
[0026] In an embodiment, controller 118 is a logic card that
provides control function to tape storage unit 100. In an
embodiment, controller 118 includes temperature program 120.
According to embodiments of the present invention, functions
managed by controller 118 include centralized management of tape
storage unit 100 and sending read/write instructions to read/write
head 104 for retrieving data from and storing data to tape 106.
[0027] In an embodiment, temperature program 120 is a program, a
subprogram of a larger program, an application, a plurality of
applications, or mobile application software, which functions to
control the temperature of left guide roller 112A, right guide
roller 112B, and tape 106 to maintain tape dimensional stability
(TDS) of tape 106 within tape storage unit 100 to prevent
read/write errors to tape 106. A program is a sequence of
instructions written by a programmer to perform a specific task.
According to embodiments of the present invention, responsive to an
absolute value of the channel offset exceeding a threshold,
temperature program 120 will power on left cooler 114A, left heater
116A, right cooler 114B, or right heater 116B, depending on (i) the
direction of travel of tape 106 and (ii) whether or not the channel
offset is positive. Temperature program 120 may run by itself but
may be dependent on system software (not shown in FIG. 1) to
execute. In one embodiment, temperature program 120 functions as a
stand-alone program residing on controller 118. In another
embodiment, temperature program 120 may work in conjunction with
other programs, applications, etc., found in tape storage unit 100.
In yet another embodiment, temperature program 120 may be found on
other computing devices (not shown in FIG. 1) in tape storage unit
100.
[0028] FIG. 2 is a schematic of an example tape storage unit with
thermoelectric devices used for cooling and conventional heating
devices used for heating, generally designated 200, in accordance
with one embodiment of the present invention. FIG. 2 provides only
an illustration of one implementation and does not imply any
limitations with regard to the different embodiments that may be
implemented. Many modifications to the depicted embodiment may be
made by those skilled in the art without departing from the scope
of the invention as recited by the claims.
[0029] In an embodiment, tape storage unit 200 includes the
following previously discussed features: left tape storage reel
102A, right tape storage reel 102B, read/write head 104, tape 106,
left guide roller 112A, right guide roller 112B, left cooler 114A,
right cooler 114B, left heater 116A, right heater 116B, controller
118, and temperature program 120. In the embodiment however, left
heater 116A and right heater 116B are not thermoelectric devices,
but instead are conventional heating devices. The new features will
be discussed in detail in the following paragraphs.
[0030] According to embodiments of the present invention, left
heater 116A is a heater used to directly heat tape 106. In various
embodiments, left heater 116A is a heating element, a conventional
bulb, an infrared bulb, a resistor, a resistance material, a
resistance wire, and the like. In an embodiment, left heater 116A
is positioned near left tape storage reel 102A directly adjacent to
tape 106 to provide efficient heating of tape 106 as it moves
toward read/write head 104. In an embodiment, right heater 116B is
substantially similar to left heater 116A with the exception of
being positioned near right tape storage reel 102B directly
adjacent to tape 106.
[0031] According to embodiments of the present invention, left
cooler 114A is attached to and in intimate contact with the flat
side of left guide roller 112A and right cooler 114B is attached to
and in intimate contact with the flat side of right guide roller
112B.
[0032] FIG. 3 is a flowchart of workflow 300 depicting an approach
for controlling the temperature within a tape drive to maintain the
dimensional stability of the media within the tape drive. In one
embodiment, the method of workflow 300 is performed by temperature
program 120. In an alternative embodiment, the method of workflow
300 may be performed by any other program working with temperature
program 120. In an embodiment, a user may invoke workflow 300 upon
powering on tape storage unit 100 or tape storage unit 200. In an
alternative embodiment, a user may invoke workflow 300 upon
accessing temperature program 120.
[0033] In an embodiment, temperature program 120 determines whether
read/write is enabled (decision step 302). In other words,
temperature program 120 determines whether a tape drive storage
unit is writing data to a tape media or reading data from a tape
media. In an embodiment (decision step 302, YES branch),
temperature program 120 determines that read/write is enabled on
the tape drive storage unit; therefore, temperature program 120
proceeds to decision step 304 to determine whether the absolute
value of the channel offset exceeds a threshold value. In the
embodiment (decision step 302, NO branch), temperature program 120
determines that read/write is not enabled on the tape drive storage
unit; therefore, temperature program 120 proceeds to step 306 to
power off any heaters or coolers that are running.
[0034] In an embodiment, temperature program 120 determines whether
an absolute value of a channel offset exceeds a threshold (decision
step 304). In other words, responsive to determining that
read/write is enabled in the tape drive storage unit, temperature
program 120 determines whether the absolute value of the channel
offset within tape drive 200 exceeds a threshold value. According
to embodiments of the present invention, a servo system (not shown)
is used to determine the channel offset. In an embodiment, the
channel offset is the difference in two spans, where the first span
is the distance between the read/write head servo reader elements
and second span is the distance between the servo patterns on the
tape media. When the first span minus the second span is positive,
the tape is too narrow and needs to be expanded. When the first
span minus the second span is not positive (i.e., negative), the
tape is too wide and second span needs to be reduced. For example,
a negative channel offset (i.e., "0-2=-2") indicates that the tape
is too wide and needs to be cooled to shrink the tape while a
positive channel offset (i.e., "0-(-2)=2") indicates that the tape
is too narrow and needs to be warmed to expand the tape. In an
embodiment (decision step 304, NO branch), temperature program 120
determines that the absolute value of the channel offset does not
exceed a threshold value; therefore, temperature program 120
proceeds to step 306 to turn off all heater/cooler power. In the
embodiment (decision step 304, YES branch), temperature program 120
determines that the absolute value of the channel offset does
exceed a threshold value; therefore, temperature program 120
proceeds to decision step 308 to determine whether the tape media
in the tape drive storage unit is traveling in the forward
direction.
[0035] In an embodiment, temperature program 120 turns
heater/cooler power off (step 306). In other words, responsive to
(i) determining that read/write is not enabled in the tape drive
storage unit and/or (ii) that the absolute value of the channel
offset does not exceed a threshold value, temperature program 120
powers off any cooler that is powered on as cooling is not required
within the tape drive storage unit.
[0036] In an embodiment, temperature program 120 determines whether
the direction of movement is forward (decision step 308). In other
words, responsive to determining that read/write is enabled in the
tape drive storage unit and the absolute value of the channel
offset exceeds a threshold value, temperature program 120
determines whether the tape media is traveling in the forward
direction. In an embodiment (decision step 308, YES branch),
temperature program 120 determines that the tape media is traveling
in the forward direction; therefore, temperature program 120
proceeds to step 310 to determine if the channel offset is
positive. In the embodiment (decision step 308, NO branch),
temperature program 120 determines that the tape media is not
traveling in the forward direction (i.e., the tape media is
traveling in the backward direction); therefore, temperature
program 120 proceeds to step 312 to determine if the channel offset
is positive.
[0037] According to an embodiment of the present invention,
temperature program 120 determines whether the channel offset is
positive (decision step 310). In other words, responsive to
determining that the tape media is moving in the forward direction,
temperature program 120 determines whether the value of the channel
offset within tape drive 200 is positive. In an embodiment
(decision step 310, YES branch), temperature program 120 determines
that the channel offset is positive; therefore, temperature program
120 proceeds to step 314 to turn on left cooler 114A. In the
embodiment (decision step 310, NO branch), temperature program 120
determines that the channel offset is not positive; therefore,
temperature program 120 proceeds to step 316 to turn on left heater
116A.
[0038] According to an embodiment of the present invention,
temperature program 120 determines whether the channel offset is
positive (decision step 312). In other words, responsive to
determining that the tape media is not moving in the forward
direction, temperature program 120 determines whether the value of
the channel offset within tape drive 200 is positive. In an
embodiment (decision step 312, YES branch), temperature program 120
determines that the channel offset is positive; therefore,
temperature program 120 proceeds to step 318 to turn on right
cooler 114B. In the embodiment (decision step 312, NO branch),
temperature program 120 determines that the channel offset is not
positive; therefore, temperature program 120 proceeds to step 320
to turn on right heater 116B.
[0039] In an embodiment, temperature program 120 turns on power to
the left cooler (step 314). In other words, responsive to
determining that read/write is enabled in the tape drive storage
unit, the absolute value of the channel offset exceeds a threshold
value, the tape media is traveling in the forward direction, and
the value of the channel offset is positive, temperature program
120 powers on left cooler. In a first example, referring to FIG. 1,
tape 106 is traveling in forward direction 108A (i.e., tape 106 is
coming off of left tape storage reel 102A, passing under read/write
head 104, and is being wound onto right tape storage reel 102B). In
the first example, left cooler 114A is powered on by temperature
program 120 in order to cool left guide roller 112A, the associated
guide roller bearings, and tape 106. In a second example, referring
to FIG. 2, tape 106 is traveling in forward direction 108A (i.e.,
tape 106 is coming off of left tape storage reel 102A, passing
under read/write head 104, and is being wound onto right tape
storage reel 102B). In the second example, left cooler 114A is
powered on by temperature program 120 in order to cool left guide
roller 112A, the associated guide roller bearings, and tape
106.
[0040] In an embodiment, temperature program 120 turns on power to
the left heater (step 316). In other words, responsive to
determining that read/write is enabled in the tape drive storage
unit, the absolute value of the channel offset exceeds a threshold
value, the tape media is traveling in the forward direction, and
the value of the channel offset is not positive, temperature
program 120 powers on left heater. In a third example, referring to
FIG. 1, tape 106 is traveling in forward direction 108A (i.e., tape
106 is coming off of left tape storage reel 102A, passing under
read/write head 104, and is being wound onto right tape storage
reel 102B). In the third example, left heater 116A is powered on by
temperature program 120 in order to heat left guide roller 112A,
the associated guide roller bearings, and tape 106. In a fourth
example, referring to FIG. 2, tape 106 is traveling in forward
direction 108A (i.e., tape 106 is coming off of left tape storage
reel 102A, passing under read/write head 104, and is being wound
onto right tape storage reel 102B). In the fourth example, left
heater 116A is powered on by temperature program 120 in order to
heat tape 106.
[0041] In an embodiment, temperature program 120 turns on power to
the right cooler (step 318). In other words, responsive to
determining that read/write is enabled in the tape drive storage
unit, the absolute value of the channel offset exceeds a threshold
value, the tape media is not traveling in the forward direction,
and the value of the channel offset is positive, temperature
program 120 powers on right cooler. In a fifth example, referring
to FIG. 1, tape 106 is traveling in backward direction 108B (i.e.,
tape 106 is coming off of right tape storage reel 102B, passing
under read/write head 104, and is being wound onto left tape
storage reel 102A). In the fifth example, right cooler 114B is
powered on by temperature program 120 in order to cool right guide
roller 112B, the associated guide roller bearings, and tape 106. In
a sixth example, referring to FIG. 2, tape 106 is traveling in
backward direction 108B (i.e., tape 106 is coming off of right tape
storage reel 102B, passing under read/write head 104, and is being
wound onto left tape storage reel 102A). In the sixth example,
right cooler 114B is powered on by temperature program 120 in order
to cool right guide roller 112B, the associated guide roller
bearings, and tape 106.
[0042] In an embodiment, temperature program 120 turns on power to
the right heater (step 320). In other words, responsive to
determining that read/write is enabled in the tape drive storage
unit, the absolute value of the channel offset exceeds a threshold
value, the tape media is not traveling in the forward direction,
and the value of the channel offset is not positive, temperature
program 120 powers on right heater. In a seventh example, referring
to FIG. 1, tape 106 is traveling in backward direction 108B (i.e.,
tape 106 is coming off of right tape storage reel 102B, passing
under read/write head 104, and is being wound onto left tape
storage reel 102A). In the seventh example, right heater 116B is
powered on by temperature program 120 in order to heat right guide
roller 112B, the associated guide roller bearings, and tape 106. In
an eighth example, referring to FIG. 2, tape 106 is traveling in
backward direction 108B (i.e., tape 106 is coming off of right tape
storage reel 102B, passing under read/write head 104, and is being
wound onto left tape storage reel 102A). In the eighth example,
right heater 116B is powered on by temperature program 120 in order
to heat tape 106.
[0043] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a," "an," and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
[0044] Having described embodiments of an approach for controlling
the temperature of a tape drive to improve the track-following
performance of the media within the tape drive (which are intended
to be illustrative and not limiting), it is noted that
modifications and variations may be made by persons skilled in the
art in light of the above teachings. It is therefore to be
understood that changes may be made in the particular embodiments
disclosed which are within the scope of the invention as outlined
by the appended claims.
[0045] FIG. 4 depicts computer system 400, which is an example of a
system that includes temperature program 120. Computer system 400
includes processor(s) 401, cache 403, memory 402, persistent
storage 405, communications unit 407, input/output (I/O)
interface(s) 406 and communications fabric 404. Communications
fabric 404 provides communications between cache 403, memory 402,
persistent storage 405, communications unit 407, and input/output
(I/O) interface(s) 406. Communications fabric 404 can be
implemented with any architecture designed for passing data and/or
control information between processors (such as microprocessors,
communications and network processors, etc.), system memory,
peripheral devices, and any other hardware components within a
system. For example, communications fabric 404 can be implemented
with one or more buses or a crossbar switch.
[0046] Memory 402 and persistent storage 405 are computer readable
storage media. In this embodiment, memory 402 includes random
access memory (RAM). In general, memory 402 can include any
suitable volatile or non-volatile computer readable storage media.
Cache 403 is a fast memory that enhances the performance of
processors 401 by holding recently accessed data, and data near
recently accessed data, from memory 402.
[0047] Program instructions and data used to practice embodiments
of the present invention may be stored in persistent storage 405
and in memory 402 for execution by one or more of the respective
processors 401 via cache 403. In an embodiment, persistent storage
405 includes a magnetic hard disk drive. Alternatively, or in
addition to a magnetic hard disk drive, persistent storage 405 can
include a solid state hard drive, a semiconductor storage device,
read-only memory (ROM), erasable programmable read-only memory
(EPROM), flash memory, or any other computer readable storage media
that is capable of storing program instructions or digital
information.
[0048] The media used by persistent storage 405 may also be
removable. For example, a removable hard drive may be used for
persistent storage 405. Other examples include optical and magnetic
disks, thumb drives, and smart cards that are inserted into a drive
for transfer onto another computer readable storage medium that is
also part of persistent storage 405.
[0049] Communications unit 407, in these examples, provides for
communications with other data processing systems or devices. In
these examples, communications unit 407 includes one or more
network interface cards. Communications unit 407 may provide
communications through the use of either or both physical and
wireless communications links. Program instructions and data used
to practice embodiments of the present invention may be downloaded
to persistent storage 405 through communications unit 407.
[0050] I/O interface(s) 406 allows for input and output of data
with other devices that may be connected to each computer system.
For example, I/O interface 406 may provide a connection to external
devices 408 such as a keyboard, keypad, a touchscreen, and/or some
other suitable input device. External devices 408 can also include
portable computer readable storage media such as, for example,
thumb drives, portable optical or magnetic disks, and memory cards.
Software and data used to practice embodiments of the present
invention can be stored on such portable computer readable storage
media and can be loaded onto persistent storage 405 via I/O
interface(s) 406. I/O interface(s) 406 also connect to display
409.
[0051] Display 409 provides a mechanism to display data to a user
and may be, for example, a computer monitor.
[0052] The present invention may be a system, a method, and/or a
computer program product at any possible technical detail level of
integration. The computer program product may include a computer
readable storage medium (or media) having computer readable program
instructions thereon for causing a processor to carry out aspects
of the present invention.
[0053] The computer readable storage medium can be a tangible
device that can retain and store instructions for use by an
instruction execution device. The computer readable storage medium
may be, for example, but is not limited to, an electronic storage
device, a magnetic storage device, an optical storage device, an
electromagnetic storage device, a semiconductor storage device, or
any suitable combination of the foregoing. A non-exhaustive list of
more specific examples of the computer readable storage medium
includes the following: a portable computer diskette, a hard disk,
a random access memory (RAM), a read-only memory (ROM), an erasable
programmable read-only memory (EPROM or Flash memory), a static
random access memory (SRAM), a portable compact disc read-only
memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a
floppy disk, a mechanically encoded device such as punch-cards or
raised structures in a groove having instructions recorded thereon,
and any suitable combination of the foregoing. A computer readable
storage medium, as used herein, is not to be construed as being
transitory signals per se, such as radio waves or other freely
propagating electromagnetic waves, electromagnetic waves
propagating through a waveguide or other transmission media (e.g.,
light pulses passing through a fiber-optic cable), or electrical
signals transmitted through a wire.
[0054] Computer readable program instructions described herein can
be downloaded to respective computing/processing devices from a
computer readable storage medium or to an external computer or
external storage device via a network, for example, the Internet, a
local area network, a wide area network and/or a wireless network.
The network may comprise copper transmission cables, optical
transmission fibers, wireless transmission, routers, firewalls,
switches, gateway computers and/or edge servers. A network adapter
card or network interface in each computing/processing device
receives computer readable program instructions from the network
and forwards the computer readable program instructions for storage
in a computer readable storage medium within the respective
computing/processing device.
[0055] Computer readable program instructions for carrying out
operations of the present invention may be assembler instructions,
instruction-set-architecture (ISA) instructions, machine
instructions, machine dependent instructions, microcode, firmware
instructions, state-setting data, configuration data for integrated
circuitry, or either source code or object code written in any
combination of one or more programming languages, including an
object oriented programming language such as Smalltalk, C++, or the
like, and procedural programming languages, such as the "C"
programming language or similar programming languages. The computer
readable program instructions may execute entirely on the user's
computer, partly on the user's computer, as a stand-alone software
package, partly on the user's computer and partly on a remote
computer or entirely on the remote computer or server. In the
latter scenario, the remote computer may be connected to the user's
computer through any type of network, including a local area
network (LAN) or a wide area network (WAN), or the connection may
be made to an external computer (for example, through the Internet
using an Internet Service Provider). In some embodiments,
electronic circuitry including, for example, programmable logic
circuitry, field-programmable gate arrays (FPGA), or programmable
logic arrays (PLA) may execute the computer readable program
instructions by utilizing state information of the computer
readable program instructions to personalize the electronic
circuitry, in order to perform aspects of the present
invention.
[0056] Aspects of the present invention are described herein with
reference to flowchart illustrations and/or block diagrams of
methods, apparatus (systems), and computer program products
according to embodiments of the invention. It will be understood
that each block of the flowchart illustrations and/or block
diagrams, and combinations of blocks in the flowchart illustrations
and/or block diagrams, can be implemented by computer readable
program instructions.
[0057] These computer readable program instructions may be provided
to a processor of a general purpose computer, special purpose
computer, or other programmable data processing apparatus to
produce a machine, such that the instructions, which execute via
the processor of the computer or other programmable data processing
apparatus, create means for implementing the functions/acts
specified in the flowchart and/or block diagram block or blocks.
These computer readable program instructions may also be stored in
a computer readable storage medium that can direct a computer, a
programmable data processing apparatus, and/or other devices to
function in a particular manner, such that the computer readable
storage medium having instructions stored therein comprises an
article of manufacture including instructions which implement
aspects of the function/act specified in the flowchart and/or block
diagram block or blocks.
[0058] The computer readable program instructions may also be
loaded onto a computer, other programmable data processing
apparatus, or other device to cause a series of operational steps
to be performed on the computer, other programmable apparatus or
other device to produce a computer implemented process, such that
the instructions which execute on the computer, other programmable
apparatus, or other device implement the functions/acts specified
in the flowchart and/or block diagram block or blocks.
[0059] The flowchart and block diagrams in the Figures illustrate
the architecture, functionality, and operation of possible
implementations of systems, methods, and computer program products
according to various embodiments of the present invention. In this
regard, each block in the flowchart or block diagrams may represent
a module, segment, or portion of instructions, which comprises one
or more executable instructions for implementing the specified
logical function(s). In some alternative implementations, the
functions noted in the blocks may occur out of the order noted in
the Figures. For example, two blocks shown in succession may, in
fact, be executed substantially concurrently, or the blocks may
sometimes be executed in the reverse order, depending upon the
functionality involved. It will also be noted that each block of
the block diagrams and/or flowchart illustration, and combinations
of blocks in the block diagrams and/or flowchart illustration, can
be implemented by special purpose hardware-based systems that
perform the specified functions or acts or carry out combinations
of special purpose hardware and computer instructions.
[0060] The programs described herein are identified based upon the
application for which they are implemented in a specific embodiment
of the invention. However, it should be appreciated that any
particular program nomenclature herein is used merely for
convenience, and thus the invention should not be limited to use
solely in any specific application identified and/or implied by
such nomenclature.
* * * * *