Patent Publication Number: US-8115647-B2

Title: Reducing HDD failure caused by electromagnetic interference from wireless devices

Description:
TECHNICAL FIELD 
     The invention pertains to electromagnetic interferences and disk drives. 
     BACKGROUND ART 
     Direct access storage devices (DASD) are integral in everyday life, and as such, expectations and demands continually increase for greater speed for manipulating and for holding larger amounts of data. To meet these demands for increased performance, the mechano-electrical assembly in a DASD device, specifically the Hard Disk Drive (HDD) has evolved to meet these demands. 
     Many processes in the fabrication of an HDD are commonly performed in a “clean room” environment, e.g., being dust free, static and/or electromagnetic free, oxygen filtered, specific clothing requirements (clean room suits), and the like. 
     Many of the various persons and/or operators entering a clean room are inadvertently remiss in powering down/off their wireless communication device(s), e.g., cell phones, pagers, PDAs or other wirelessly configured portable computer system/device. Operable wireless communication devices have been observed to cause electro magnetic interference (EMI) induced damage during HDD fabrication. 
     SUMMARY OF THE INVENTION 
     A system and method for reducing electromagnetic interference caused hard disk drive failure is described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention: 
         FIG. 1  is a block diagram of an environment for reducing electromagnetic interference caused hard disk drive failure in accordance with embodiments of the present invention. 
         FIG. 2  is a block diagram of environment having an electromagnetic interference restricted region and upon which various embodiments of the present invention may be practiced, in an embodiment of the present invention. 
         FIG. 3  is a block diagram of components in a system for reducing electromagnetic interference induced hard disk drive damage, in accordance with an embodiment of the present invention. 
         FIG. 4  is flowchart of a process for reducing electromagnetic interference induced hard disk drive damage, in accordance with an embodiment of the present invention. 
         FIG. 5  is a block diagram of components of an exemplary wireless device upon which embodiments of the present invention may be practiced, in accordance with embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to embodiment(s) of the present invention. While the invention will be described in conjunction with the embodiment(s), it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. 
     Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be recognized by one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well known methods, procedures, and components have not been described in detail as not to unnecessarily obscure aspects of the present invention. 
     Some portions of the detailed description, which follow, are presented in terms of procedures, steps, logic blocks, processing, and other symbolic representations of operations on data bits that can be performed by computer systems. These descriptions and representations are used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. A process, etc., is here, and generally, conceived to be a self-consistent sequence of operations or instructions leading to a desired result. The operations are those requiring physical manipulations of physical quantities. Usually, though not necessarily, those quantities take the form of electrical, electronic, magnetic, optical, and/or electro-optical signals, capable of being stored, transferred, combined, compared, and otherwise manipulated in a computer system. It has been proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. 
     It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities. Unless specifically stated otherwise, and as apparent from the following discussions, it is noted that throughout the present invention, the terms used herein refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the communications and computer systems&#39; registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission, or display device. 
     Certain portions of the detailed description of embodiments the present invention, which follow, are presented in terms of processes (e.g., process  400  of  FIG. 4 ). These processes are, in an embodiment of the present invention, carried out by processors and electrical and electronic components under the control of computer readable and computer executable instructions. The computer readable and computer executable instructions reside, for example, in registers and other features of processors, memories, and data storage features of computers executing programs and processes. However, the computer readable and computer executable instruction may reside in any type of computer readable medium. Although specific portions are disclosed in figures herein describing the operations of processes, e.g.,  FIG. 4 ; describing processes, e.g., process  400 , such portions are exemplary. That is, the present invention is well suited to performing various others portions or variations of the portions recited in the flowchart of the figures herein. Further, it is appreciated that the steps of the processes may be performed by software, firmware, hardware, or any combination of software and firmware and hardware. 
     Overview 
     With reference now to  FIG. 1 , a block diagram of an environment  100  for reducing electromagnetic interference (EMI) induced hard disk drive (HDD) damage is shown. Environment  100  is shown to include a network  190 . Network  190  may be a wireless network, a wired network, or a combination wireless and wired network. In an embodiment of the present invention, network  190  may be a communication network located within a firewall of an organization or corporation (an “Intranet”), or network  190  may represent a portion of the World Wide Web or Internet. Portable computer devices  581 ,  582 ,  583  and  584  and system  300  are communicatively coupled via a communication line, in which the mechanisms for coupling computer systems over the Internet or over Intranets are well known in the art. This coupling can be accomplished over any network protocol, wired or wireless, that supports a network connection, such as IP (Internet Protocol), TCP (Transmission Control Protocol), UDP (User Datagram Protocol), TELNET, NetBIOS, IPX (Internet Packet Exchange), IR (infra red), RF (radio frequency), wireless broadband, Bluetooth, LU6.2, and link layers protocols such as Ethernet, token ring, and ATM (Asynchronous Transfer Mode). Alternatively, devices  581 - 584  and apparatus  300  may be coupled to network  190  via an input/output port (e.g., a serial port). It is noted that, for simplicity, four portable computer devices and a single system  300  are shown; however, it is understood that network  190  may comprise any number of portable computer devices and systems  300 . In the present embodiment, network  190  is a combination network, exhibiting functional characteristics of both a wired and a wireless network. 
     In an embodiment of the present invention, environment  100  is shown to include a region  150  (indicated with a dotted line) upon which embodiments of the present invention are directed for reducing EMI induced HDD damage, in accordance with various embodiment of the present invention. Region  150  includes a transmission signal restricted area, e.g., clean room area  200 , as described herein with reference to  FIG. 2 . In an embodiment of the present invention, area  200  may be a hard disk drive (HDD) fabrication/assembly/disassembly room. Region  150  further includes a system  300  for reducing electromagnetic interference induced damage that may be caused within area  200 , in accordance with embodiments of the present invention, and as described in detail in  FIG. 3 . In an embodiment of the present invention, system  300  is operably coupled to area  200 . 
     Still referring to  FIG. 1 , shown in network  190  are an antenna  101  and a base station  102 . In an embodiment of the present invention, transmission signals, e.g., wireless communication signals, are sent (indicated by arrow  114 ) and received (indicated by arrow  116 ) between antenna  101  and base station  102  and wireless devices that may be connected to network  190 . In an embodiment of the present invention, system  300  is configured to detect a transmission signal that may be generated by a wirelessly configured portable computer system, e.g., devices  581 ,  582  and  583 . 
     Also shown is a short range wireless device  584  that, in an embodiment of the present invention, may be a Bluetooth device, e.g., a hands-free cell phone accessory, commonly used in and around the ear of a user of a device  581 ,  582  and/or  583 . In an embodiment of the present invention, device  581  emits a signal  591 , device  582  emits a signal  592 , device  583  emits a signal  593 , and device  584  emits a signal  594 . In an embodiment of the present invention, devices  581 ,  582  and  583  may be, but are not limited to, a personal digital assistant (PDA), a cellular phone or a laptop computer system. Additionally, each device  581 ,  582  and  583  may include a device  584 , enabling localized, e.g., Bluetooth, wireless communication. 
       FIG. 2  is an expanded block diagram view of area  200  of  FIG. 1 . Area  200  includes a signal detection portion  205  and a signal restricted portion  210 , in an embodiment of the present invention. Area  200  includes a door  204  and an opening  203  enabling access to portion  205 . Area  200  further includes a door  209  and an opening  208 , disposed within portion  205 , enabling access to portion  210 . Area  200  may optionally include an emergency exit  299 . 
     In an embodiment of the present invention, system  300  is configured to detect a wireless signal that may be present within a particular physical location of area  200 . In the present embodiment, system  300  is shown configured for signal detection in monitoring region  371 . In an embodiment of the present invention, monitoring region  371  monitors signal detection portion  205  and extends outside the confines of portion  205 . 
     In an embodiment of the present invention, system  300  includes a detector  353  configured therewithin, as seen in  FIG. 3 . In an alternative embodiment of the present invention, detector  353  may be externally coupled to system  300 , such that system  300  may be disposed elsewhere within network  190 . 
     In accordance with an embodiment of the present invention, upon a portable computer device, e.g., device  581 ,  582 ,  583  and/or  584  entering signal restricted region  371 , detector  353  detects the presence of a signal generated from the portable computer device. In accordance with embodiments of the present invention, detector  353  may activate an alert/access controller  354 . Controller  354  may then activate an alert mechanism, e.g., alarm  355 , to indicate the presence of a wireless signal within region  371 , in an embodiment of the present invention. In an alternative embodiment of the present invention, controller  371  may activate an access control mechanism, e.g., access control mechanism  356 , such that entering room  210  is prevented. 
       FIG. 3  is a block diagram illustrating components and circuitry of an exemplary computer system  380 , which can be implemented as a system  300  as described herein with reference to  FIGS. 1 ,  2  and  4 , in accordance with embodiments of the present invention. Computer system  380  includes an address/data bus  310  for communicating information, a central processor  301  coupled with the bus for processing information and instructions, a volatile memory  302  (e.g., random access memory, RAM) coupled with the bus  310  for storing information and instructions for the central processor  301  and a non-volatile memory  303  (e.g., read only memory, ROM) coupled with the bus  310  for storing static information and instructions for the processor  301 . Optionally, computer system  300  can include non-volatile cache  304  and dynamic ROM (DROM, not shown). It is noted that in an embodiment, computer system  380  can be configured with a plurality of processors  301 . 
     Computer system  380  of  FIG. 3  also includes a data storage device  360  coupled with bus  310  for storing instructions and information. In the present embodiment, data storage device  360  also includes a set of instructions  399  for monitoring a network for signals in a signal restricted area, e.g., area  200  of  FIGS. 1 and 2 , in accordance with an embodiment of the present invention. Instructions  399  enable computer system  380  to monitor a restricted signal region, e.g., region  371 , for signal presence, in an embodiment of the present invention, and as described herein with reference to  FIGS. 1-5 . 
     It is noted that instructions  399  are shown stored within a data storage device, e.g.,  360 , in which data is stored in a relatively permanent environment. However, in an alternative embodiment, portions of instructions  399  may be combinationally distributed among non-volatile memory, e.g., ROM  303  and cache  304  and a data storage device  360 . Data storage device  360  can be, for example, an HDD (hard disk drive), an FDD (floppy disk drive), a compact memory device, a CD-RW (compact disk with write functionality), a DVD-RW or DVD+RW (digital versatile disk with + or − write functionality), a dual layer DVD, a tape drive, a USB drive, etc., and furthermore device  360  can be in multiples or in a combination thereof. Data storage device  360  may also be local or remote to the computer system, plurally instanced, removable, and/or hot swappable (connected or unconnected while computer system is powered). 
     Computer system  380  is also shown to include a signal detector  353  coupled to bus  301 , in an embodiment of the present invention. Detector  353  is configured to monitor a signal restricted region, e.g., region  371 , within a wireless network, e.g., network  190 , for the presence of a wireless signal, e.g., signals  591 - 594  generated by a portable computer device  581 - 584 , respectively. In an embodiment of the present invention, upon detection of a wireless signal within region  371 , instructions  399  may activate an alert/access controller, e.g., alert/access controller  354 . In an embodiment of the present invention, upon activation, controller  354  may cause activation of an alerting device, e.g., alert device  355 . In an embodiment of the present invention, alert device  355  may produce an audible sound to indicate the presence of a signal within signal restricted region  371 . In another embodiment of the present invention, alert device  355  may produce a visible indicator to indicate the presence of a signal within signal restricted region  371 . 
     In an embodiment of the present invention, controller  354  may be further configured to control access to the restricted area, e.g., clean room  210 . In accordance with an embodiment of the present invention, controller  354  may interact with access control device  356  so to render door  209  inoperable, such that access to room  210  is prevented. 
     In accordance with various embodiments of the present invention, alert device  355  and/or access control device  356  may be deactivated upon removal of the detected signal, e.g., when the detected signal is removed from region  371  or when the device generating the detected signal is powered off. 
     With reference still to  FIG. 3 , computer system  380  also includes a network communication device  335 , which is coupled to bus  310  for providing a communication link between computer system  300 , and a network environment, e.g., network environment  150  of  FIG. 1 . As such, network communication device  335  enables central processor unit  301  to communicate with other electronic systems coupled to the network, e.g., network  150  of  FIG. 1 . It is noted that the present embodiment of network communication device  335  is well suited to be implemented in a wide variety of ways. In one example, network communication device  335  is coupled to an antenna and provides the functionality to transmit and receive information over a wireless communication interface, e.g., Bluetooth, IR (infra-red), RF (radio frequency), satellite and the like. In another example, network communication device  335  could be implemented as a modem, wired or wireless. In yet another example, network communication device  335  could be configured as a NIC (network interface card), wired or wireless. 
     Still referring to  FIG. 3 , network communication device  335 , in an embodiment, includes an optional digital signal processor (DSP)  320  for processing data to be transmitted or data that are received via network communication device  335 . Alternatively, processor  301  can perform some or all of the functions performed by DSP  320 . 
     Also included in computer system  380  of  FIG. 3  is an optional alphanumeric input device  306 . In an implementation, device  306  is a keyboard. Device  306  can be physically coupled to computer system  380 . Alternatively, device  306  may be wirelessly coupled to computer system  380 . Alphanumeric input device  306  can communicate information and command selections to processor  301 . 
     System  380  of  FIG. 3  also includes an optional cursor control or directing device (on-screen cursor control)  307  coupled to bus  310  for communicating user input information and command selections to processor  301 . In another common implementation, on-screen cursor control device  307  is a mouse or similar pointing device. 
     System  380  also contains a display device  305  coupled to the bus  310  for displaying information to the computer user. 
     Although embodiments of the present invention are shown implemented in a disk drive  111  that is configured with four hard disks and three actuator arm assemblies, it is noted that embodiments of the present invention are well suited for utilization in hard disk drives with a greater number or lesser number of hard disks as well as hard disk drives having a greater number or lesser number of actuator arm assemblies. As such, hard disk drives shown and described herein, and upon which embodiments of the present invention may be practiced, are exemplary in nature are not to be construed as a limitation. 
       FIG. 4  is a flowchart of a process  400  for maintaining a servo signal in accordance with various embodiments of the invention. Process  400  includes exemplary operations of various embodiments of the invention which can be carried out by a processor(s) and electrical components under the control of computing device readable and executable instructions (or code), e.g., instructions  399 . The computing device readable and executable instructions (or code) may reside, for example, in data storage features such as volatile memory, non-volatile memory and/or mass data storage that are usable by a computing device. However, the computing device readable and executable instructions (or code) may reside in any type of computing device readable medium. Although specific operations are disclosed in process  400 , such operations are exemplary. That is, process  400  may not include all of the operations illustrated by  FIG. 5 . Also, process  400  may include various other operations and/or variations of the operations shown by  FIG. 4 . Likewise, the sequence of the operations of process  400  can be modified. It is noted that the operations of process  400  can be performed by software, by firmware, by hardware, or by any combination thereof. 
     Process  400  for reducing electromagnetic interference caused damage will be described with reference to components and devices shown in  FIGS. 1-3 , and  FIG. 5 , in accordance with embodiments of the present invention. 
     In operation  402  of process  400 , a signal restricted area, e.g., region  371  of area  200  is monitored for the presence of a signal that may be generated by a portable computer device, e.g., portable computer devices  581 - 584  of  FIG. 1  and  FIG. 5 . In an embodiment of the present invention signal detector  353  monitors region  371  for wireless signal presence. If a powered on portable computer device, e.g.,  591 - 594  of  FIG. 1 , enters region  371 , signal detector  353  detects the signal generated thereby. In an embodiment of the present invention, opening of door  204  may activate operation of signal detector  353 . 
     In operation  404  of process  400 , upon detection of a portable computer system signal in region  371 , e.g., signals  591 - 594 , by signal detector  353 , detector  353  activates an alert/access controller, e.g., controller  354 . In accordance with an embodiment of the present invention, controller  354  may activate alarm  355 , indicating presence of a signal in signal restricted region  371 . In another embodiment of the present invention, controller  354  may activate access control device  356  so as to control operation of door  209 , such that door  209  is not operational, such that access to room  210  is prevented. 
     In process  406  of process  400 , once the detected signal is no longer present within signal restricted region  371 , e.g., by either removing the portable computer device from the signal restricted region or by powering down the portable device, controller  354  deactivates the alerting mechanism, e.g., alarm  355  or access control device  356 . If continued monitoring of a signal restricted region is warranted, process  400  returns to operation  402 . It is noted that subsequent to completion of operation  406 , process  400  may be also terminated. 
     It is noted that although various embodiments of the present invention are shown implemented in a hard disk drive fabrication environment, e.g., area  200 , embodiments of the present invention are well suited to be implemented in alternative environments. For example, embodiments of the present invention may be implemented in a public transportation facility, e.g., an airport, in which area  150  may be a boarding gate, opening  203  may be a door proximal to the boarding gate and opening  208  may be the entrance to an airplane. In another example, embodiments of the present invention may be implemented in a health care facility, e.g., a hospital, in which area  150  may be, but is not limited to, a surgical environment having a pre-operative region  205  and an operating region  210 . In yet another example, area  150  may be forensics laboratory. In each example, embodiments of the present invention may be configured to provide detection of a wireless signal, thus preventing the introduction of electromagnetic interference within a signal restricted region. 
       FIG. 5  is a block diagram illustrating components and circuitry of an exemplary portable computer system  580 , upon which various embodiments of the present invention may be practiced. Portable computer system  580  can be implemented as, but is not limited to, a cellular phone, a personal digital assistant, a laptop computer system, etc. It is noted that portable devices  581 ,  582 ,  583  and  584  may each implemented with some or all of the components and circuitry of portable computer system  580 . 
     Portable computer system  580  includes an address/data bus  510  for communicating information, a central processor  501  coupled with the bus for processing information and instructions, a volatile memory  502  (e.g., random access memory, RAM) coupled with the bus  510  for storing information and instructions for the central processor  501  and a non-volatile memory  503  (e.g., read only memory, ROM) coupled with the bus  510  for storing static information and instructions for the processor  401 . Optionally, portable computer system  580  can include dynamic ROM (DROM, not shown). It is noted that in an embodiment, portable computer system  580  can be configured with a plurality of processors  501 . 
     Portable computer system  580  of  FIG. 5  also includes a data storage device  560  coupled with bus  510  for storing instructions and information. Data storage device  560  can be, for example, an HDD (hard disk drive), an FDD (floppy disk drive), a compact memory device, a CD-RW (compact disk with write functionality), a DVD-RW or DVD+RW (digital versatile disk with + or − write functionality), a dual layer DVD, a tape drive, a USB drive, etc., and furthermore device  560  may be implemented in multiples or in a combination thereof within portable computer system  580 . Data storage device  560  may also be local or remote to the computer system, plurally instanced, removable, and/or hot swappable (connected or unconnected while computer system is powered). 
     With reference still to  FIG. 5 , device  580  includes a network communication device  535 , which is coupled to bus  510  for providing a communication link between device  580 , and a network environment, e.g., network environment  190  of  FIG. 1 . As such, network communication device  535  enables central processor unit  501  to communicate with other electronic systems coupled to the network, e.g., network  190  of  FIG. 1 . It is noted that the present embodiment of network communication device  535  is well suited to be implemented in a wide variety of ways. 
     In one example, network communication device  535  is coupled to an antenna and provides the functionality to transmit and receive information over a wireless communication interface  590 , e.g., Bluetooth, IR (infra-red), RF (radio frequency), satellite and the like. In another example, network communication device  535  could be implemented as a modem, e.g., a wired connection  540  or a wireless connection  590 . In yet another example, network communication device  535  could be configured as a NIC (network interface card), having wired ( 540 ) or wireless ( 590 ) connectivity to network  190 . 
     It is noted that portable computer system  580 , when configured with a network communication device  535  having wireless connective functionality produces a signal containing a frequency energy while powered on, in a manner mode (e.g., on vibrate), on standby, or in any other mode in which a signal is generated by device  535 . It is upon device  535  generated signals that various embodiments of the present invention are directed. 
     Still referring to  FIG. 5 , network communication device  535 , in an embodiment, includes an optional digital signal processor (DSP)  520  for processing data to be transmitted or data that are received via network communication device  535 . Alternatively, processor  501  can perform some or all of the functions performed by DSP  520 . 
     Also included in portable computer system  580  of  FIG. 5  is an optional alphanumeric input device  506 . In an implementation, device  406  is a keyboard. Device  506  can be integrated within the form factor of portable computer system  480 . Device  506  can be physically coupled to portable computer system  480 . Alternatively, device  506  may be wirelessly coupled to portable computer system  480 . Alphanumeric input device  506  can communicate information and command selections to processor  501 . 
     Portable computer system  580  of  FIG. 5  may also include an optional cursor control or directing device (on-screen cursor control)  507  coupled to bus  510  for communicating user input information and command selections to processor  501 . In another common implementation, on-screen cursor control device  507  is a mouse or similar pointing device. 
     Portable computer system  580  also contains a display device  505  coupled to the bus  410  for displaying information to the computer user. Portable computer system may also contain a camera  508  for capturing images. 
     Accordingly, embodiments of the present invention, as described herein with reference to  FIGS. 1-5  can be utilized to reduce electromagnetic interference induced damage, in accordance with embodiments of the present invention. 
     Embodiments of the present invention, in the various presented embodiments, provide reduced electromagnetic interference caused damage in an electromagnetic interference restricted environment. 
     The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and many modifications and variations are possible in light of the above teaching. The embodiments described herein were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.