Tape drive bearing temperature control

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 a temperature within the tape drive storage unit exceeds a threshold value. In response to determining that the temperature within the tape drive storage unit exceeds the threshold value, a determination is made of a direction of travel of a tape media within the tape drive storage unit. In response to determining that the direction of travel is a forward direction, a first cooling device is powered on. The first cooling device lowers the temperature of a first guide roller and the tape media coming off a first tape storage reel prior to the tape media passing by a read/write head within the tape drive storage unit.

BACKGROUND

The present invention relates generally to the field of magnetic tape data storage, and more particularly to controlling the temperature of roller bearings within a tape drive to improve the track-following performance of the media within the tape drive.

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

Embodiments of the present invention include an apparatus for controlling the temperature of roller bearings within a tape drive storage unit to improve the track-following performance of the media within the tape drive. In one embodiment, the apparatus is comprised of the following: a first tape storage reel located on a left side of the apparatus; a second tape storage reel located on a right side of the apparatus; a tape attached to the first tape storage reel on an end of the tape and the tape also attached to the second 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 first tape storage reel and the second tape storage reel; a read/write head located in between the first tape storage reel and the second tape storage reel; a first cooling device attached to and in intimate contact with a portion of the tape transport mechanism; a second cooling device attached to and in intimate contact with another portion of the tape transport mechanism; and a controller.

Additional embodiments of the present invention include an approach for controlling the temperature of roller bearings within a tape drive storage unit to improve the track-following performance 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 a temperature within the tape drive storage unit exceeds a threshold value. In response to determining that the temperature within the tape drive storage unit exceeds the threshold value, a determination is made of a direction of travel of a tape media within the tape drive storage unit. In response to determining that the direction of travel is a forward direction, a first cooling device is powered on. The first cooling device lowers the temperature of a first guide roller and the tape media coming off a first tape storage reel prior to the tape media passing by a read/write head within the tape drive storage unit.

DETAILED DESCRIPTION

Embodiments of the present invention provide for controlling the temperature of roller bearings within a tape drive to improve the track-following performance of the media within the tape drive. Temperature fluctuations within the tape drive, along with tape path imperfections, can contribute to lateral tape motion (LTM) which negatively impacts the precise positioning of the read/write head over the data tracks on the tape media. Increased temperature within the tape drive can cause problems such as harmonic disturbance of the guide rollers, expansion of the roller barrels and roller bearing races, and less dampening of the bearing lubrication in the tape drive.

Embodiments of the present invention disclose an approach for controlling the temperature of roller bearings within a tape drive to improve the track-following performance of the media within the tape drive. In an embodiment, thermoelectric cooling devices (such as Peltier coolers) are placed inside the tape drive and are used to cool the tape media, guide rollers, and/or tape guides, which helps to control the expansion of the various components in an effort to maintain positional accuracy of the head relative to the data tracks of the media.

As referred to herein, certain components in this specification are substantially identical with the exception of a “first side” versus “second side” position and arrangement within the tape drive (e.g., inFIG. 1, first tape storage reel102A and second tape storage reel102B). In those situations where components are substantially identical, only one of the substantially identical components will be described in detail (e.g., only first tape storage reel102A will be described in detail).

FIG. 1is a schematic of an example tape storage unit with first and second guide rollers, generally designated100, in accordance with one embodiment of the present invention.FIG. 1provides 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.

In an embodiment, tape storage unit100includes first tape storage reel102A, second tape storage reel102B, read/write head104, tape106, first cooler110A, second cooler110B, first guide roller112A, second guide roller112B, controller118, and cooling program120.

In an embodiment, first tape storage reel102A is an open reel made of a plastic, a similar material, or any material suitable for the application, used to either collect or dispense the tape media as the tape media travels across read/write head104within tape storage unit100. In an embodiment, first tape storage reel102A is ninety-seven plus or minus one millimeter in diameter. In another embodiment, first tape storage reel102A can be any diameter. According to embodiments of the present invention, first tape storage reel102A may be contained within a cartridge or a cassette instead of being an open reel. In an embodiment, second tape storage reel102B is substantially similar to first tape storage reel102A.

In an embodiment, read/write head104is a type of transducer in tape storage unit100used to convert electrical signals to magnetic fluctuations and vice versa for writing and reading, respectively, data to and/or from tape106. In an embodiment, read/write head104includes 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 tape106when passing adjacent to read/write head104. In this manner, read/write head104changes the electrical polarity of the bits on tape106resulting in data records being written (i.e., stored) to tape106as a series of zeroes and ones for digital data. Reversing the process induces an electrical current across the small air gap allowing read/write head104to read (i.e., retrieve) data from tape106. 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.

In an embodiment, tape106is the media within tape storage unit100that data is written to or read from via read/write head104. In an embodiment, tape106includes 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, tape106includes 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 tape106available for data storage.

In an embodiment, forward direction108A is a direction of travel for tape106when tape106is coming off of first tape storage reel102A and being wound onto second tape storage reel102B.

In an embodiment, backward direction108B is the opposite direction of travel of tape106from forward direction108A.

In an embodiment, first cooler110A is a thermoelectric cooling device (e.g., a Peltier cooler) used to lower the temperature of first guide roller112A and tape106within tape storage unit100. In an embodiment, first cooler110A is attached to and in intimate contact with one side of first guide roller112A. According to embodiments of the present invention, first cooler110A uses the Peltier effect to create a heat flux between the junction of two different types of materials. First cooler110A 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, second cooler110B is substantially similar to first cooler110A with the exception that second cooler110B is attached to and in intimate contact with one side of second guide roller112B.

In an embodiment, first guide roller112A is a sub-assembly component of the tape transport mechanism within tape storage unit100that guides tape106as tape106moves between first tape storage reel102A and read/write head104. According to an embodiment of the present invention, first guide roller112A is shown inFIG. 5by sub-assembly500which consists of main cylinder502constrained to stationary shaft508by two roller bearing sub-assemblies (i.e., outer roller bearing sub-assembly504and inner roller bearing sub-assembly506) which allow free rotation of main cylinder502around stationary shaft508. In an embodiment, first guide roller112A changes the direction of travel of tape106by ninety degrees plus or minus two degrees. According to an embodiment of the present invention, first guide roller112A is made from stainless steel. According to another embodiment, first guide roller112A is made from a non-stainless steel with a coating. According to yet another embodiment, first guide roller112A is made from any type of material used to construct guide rollers in a transport mechanism within a tape drive storage unit. In an embodiment, second guide roller112B is substantially similar to first guide roller112A with the exception that second guide roller112B guides tape106as tape106moves between second tape storage reel102B and read/write head104.

In an embodiment, controller118is a logic card that provides control function to tape storage unit100. In an embodiment, controller118includes cooling program120. According to embodiments of the present invention, functions managed by controller118include centralized management of tape storage unit100and sending read/write instructions to read/write head104for retrieving data from and storing data to tape106.

In an embodiment, cooling program120is 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 tape106, first guide roller112A (or second guide roller112B) to improve the track-following performance of tape106within tape storage unit100. 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 a temperature exceeding a threshold, cooling program120will power on first cooler110A or second cooler110B, depending on the direction of travel of tape106. Cooling program120may run by itself but may be dependent on system software (not shown inFIG. 1) to execute. In one embodiment, cooling program120functions as a stand-alone program residing on controller118. In another embodiment, cooling program120may work in conjunction with other programs, applications, etc., found in tape storage unit100. In yet another embodiment, cooling program120may be found on other computing devices (not shown inFIG. 1) in tape storage unit100.

FIG. 2is a schematic of an example tape storage unit with first and second guide rollers replaced by first and second tape guides, generally designated200, in accordance with one embodiment of the present invention.FIG. 2provides 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.

In an embodiment, tape storage unit200includes the following previously discussed features: first tape storage reel102A, second tape storage reel102B, read/write head104, tape106, first cooler110A, second cooler110B, controller118, and cooling program120. In the embodiment, tape storage unit200includes new features first roller114A, second roller114B, first tape guide116A, and second tape guide116B which replace first guide roller112A and second guide roller112B. The new features will be discussed in detail in the following paragraphs.

In an embodiment, first roller114A is a sub-assembly component of the tape transport mechanism within tape storage unit200that moves tape106as tape106travels between first tape storage reel102A and read/write head104. In an embodiment, first roller114A is shown inFIG. 5by sub-assembly500which consists of main cylinder502constrained to stationary shaft508by two roller bearing sub-assemblies (i.e., outer roller bearing sub-assembly504and inner roller bearing sub-assembly506) which allow free rotation of main cylinder502around stationary shaft508. According to an embodiment of the present invention, first roller114A is made from stainless steel. According to another embodiment, first roller114A is made from non-stainless steel with a coating. According to yet another embodiment, first roller114A is made from any type of material used to construct rollers in a transport mechanism within a tape drive storage unit. In an embodiment, first roller114A is positioned between first tape guide116A and read/write head104. In an embodiment, second roller114B is substantially similar to first roller114A with the exception that second roller114B is positioned between second tape guide116B and read/write head104.

In an embodiment, first tape guide116A is a component of the tape transport mechanism within tape storage unit200that moves tape106as tape106travels between first tape storage reel102A and read/write head104. In an embodiment, first tape guide116A includes a curved side, which contacts tape106as tape106moves within tape storage unit200, and a flat side opposite the curved side. According to an embodiment of the present invention, first tape guide116A is made from stainless steel for high thermal conductivity. In an embodiment, first tape guide116A changes the direction of travel of tape106ninety plus or minus two degrees. According to an embodiment of the present invention, first tape guide116A is positioned between first tape storage reel102A and first roller114A. In an embodiment, second tape guide116B is substantially similar to first tape guide116A with the exception that second tape guide116B is positioned between second tape storage reel102B and second roller114B.

According to embodiments of the present invention, first cooler110A is attached to and in intimate contact with the flat side of first tape guide116A and second cooler110B is attached to and in intimate contact with the flat side of second tape guide116B.

FIG. 3is a flowchart of workflow300depicting an approach for controlling the temperature of roller bearings within a tape drive to improve the track-following performance of the media within the tape drive. In one embodiment, the method of workflow300is performed by cooling program120. In an alternative embodiment, the method of workflow300may be performed by any other program working with cooling program120. In an embodiment, a user may invoke workflow300upon powering on tape storage unit100or tape storage unit200. In an alternative embodiment, a user may invoke workflow300upon accessing cooling program120.

In an embodiment, cooling program120determines whether read/write is enabled (decision step302). In other words, cooling program120determines whether a tape drive storage unit is writing data to a tape media or reading data from a tape media. In an embodiment (decision step302, YES branch), cooling program120determines that read/write is enabled on the tape drive storage unit; therefore, cooling program120proceeds to decision step304to determine whether the temperature within the tape drive storage unit exceeds a threshold value. In the embodiment (decision step302, NO branch), cooling program120determines that read/write is not enabled on the tape drive storage unit; therefore, cooling program120proceeds to step308to power off any coolers that are running.

In an embodiment, cooling program120determines whether a temperature exceeds a threshold (decision step304). In other words, responsive to determining that read/write is enabled in the tape drive storage unit, cooling program120determines whether the temperature within the tape drive storage unit exceeds a threshold value. According to embodiments of the present invention, a temperature sensor (not shown inFIG. 1) within controller118monitors the temperature within the tape drive storage unit. In an embodiment, the temperature threshold value is a value of the temperature within the tape drive storage unit above which problems, such as thermal expansion of components, effectiveness of lubrication, and increased harmonic disturbance of the guide rollers, may occur and affect track-following performance. In an embodiment (decision step304, NO branch), cooling program120determines that the temperature within the tape drive storage unit does not exceed a threshold value; therefore, cooling program120proceeds to step306to turn off cooler power. In the embodiment (decision step304, YES branch), cooling program120determines that the temperature within the tape drive storage unit exceeds a threshold value; therefore, cooling program120proceeds to decision step308to determine whether the tape media in the tape drive storage unit is traveling in the forward direction.

In an embodiment, cooling program120turns cooler power off (step306). In other words, responsive to (i) determining that read/write is not enabled in the tape drive storage unit or (ii) that a temperature within the tape storage unit does not exceed a threshold value, cooling program120powers off any cooler that is powered on as cooling is not required within the tape drive storage unit.

In an embodiment, cooling program120determines whether the direction of movement is forward (decision step308). In other words, responsive to determining that read/write is enabled in the tape drive storage unit and the temperature within the tape drive storage unit exceeds a threshold value, cooling program120determines whether the tape media is traveling in the forward direction. In an embodiment (decision step308, YES branch), cooling program120determines that the tape media is traveling in the forward direction; therefore, cooling program120proceeds to step310to power on the first cooler. In the embodiment (decision step308, NO branch), cooling program120determines that the tape media is not traveling in the forward direction; therefore, cooling program120proceeds to step312to power on the second cooler.

In an embodiment, cooling program120turns on power to the first cooler (step310). In other words, responsive to determining that read/write is enabled in the tape drive storage unit, the temperature within the tape drive storage unit exceeds a threshold value, and the tape media is traveling in the forward direction, cooling program120powers on the first cooler. In a first example, referring toFIG. 1, tape106is traveling in forward direction108A (i.e., tape106is coming off of first tape storage reel102A, passing under read/write head104, and is being wound onto second tape storage reel102B). In the first example, first cooler110A is powered on by cooling program120in order to cool first guide roller112A, the associated guide roller bearings, and tape106. In a second example, referring toFIG. 2, tape106is traveling in forward direction108A (i.e., tape106is coming off of first tape storage reel102A, passing under read/write head104, and is being wound onto second tape storage reel102B). In the second example, first cooler110A is powered on by cooling program120in order to cool first tape guide116A. first roller114A, the associated roller bearings, and tape106.

In an embodiment, cooling program120turns on power to the second cooler (step312). In other words, responsive to determining that read/write is enabled in the tape drive storage unit, the temperature within the tape drive storage unit exceeds a threshold value, and the tape media is not traveling in the forward direction, cooling program120powers on the second cooler. In a third example, referring toFIG. 1, tape106is traveling in backward direction108B (i.e., tape106is coming off of second tape storage reel102B, passing under read/write head104, and is being wound onto first tape storage reel102A). In the third example, second cooler110B is powered on by cooling program120in order to cool second guide roller112B, the associated guide roller bearings, and tape106. In a fourth example, referring toFIG. 2, tape106is traveling in backward direction108B (i.e., tape106is coming off of second tape storage reel102B, passing under read/write head104, and is being wound onto first tape storage reel102A). In the fourth example, first cooler110A is powered on by cooling program120in order to cool second tape guide116B, second roller114B, the associated roller bearings, and tape106.

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.

FIG. 4depicts computer system400, which is an example of a system that includes cooling program120. Computer system400includes processor(s)401, cache403, memory402, persistent storage405, communications unit407, input/output (I/O) interface(s)406and communications fabric404. Communications fabric404provides communications between cache403, memory402, persistent storage405, communications unit407, and input/output (I/O) interface(s)406. Communications fabric404can 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 fabric404can be implemented with one or more buses or a crossbar switch.

Memory402and persistent storage405are computer readable storage media. In this embodiment, memory402includes random access memory (RAM). In general, memory402can include any suitable volatile or non-volatile computer readable storage media. Cache403is a fast memory that enhances the performance of processors401by holding recently accessed data, and data near recently accessed data, from memory402.

Program instructions and data used to practice embodiments of the present invention may be stored in persistent storage405and in memory402for execution by one or more of the respective processors401via cache403. In an embodiment, persistent storage405includes a magnetic hard disk drive. Alternatively, or in addition to a magnetic hard disk drive, persistent storage405can 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.

The media used by persistent storage405may also be removable. For example, a removable hard drive may be used for persistent storage405. 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 storage405.

Communications unit407, in these examples, provides for communications with other data processing systems or devices. In these examples, communications unit407includes one or more network interface cards. Communications unit407may 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 storage405through communications unit407.

I/O interface(s)406allows for input and output of data with other devices that may be connected to each computer system. For example, I/O interface406may provide a connection to external devices408such as a keyboard, keypad, a touchscreen, and/or some other suitable input device. External devices408can 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 storage405via I/O interface(s)406. I/O interface(s)406also connect to display409.