Abstract:
A self-biasing storage device sled for mounting a storage device within a chassis is provided. The self-biasing storage device sled includes a bezel, which includes a first portion that is stationary relative to a storage device, a second portion vertically captured within the first portion and configured to slide between unlatching and latching positions, and a spring configured to push the latch outwardly from the bezel. The second portion includes a finger-movable member, a latch, and a horizontal biasing feature adjacent to the latch and configured to move in concert with the latch. When the storage device is installed in the chassis, the horizontal biasing feature exerts force against a first chassis interior side surface and biases the storage device sled against a second chassis interior side surface.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application is related to pending non-Provisional U.S. application Ser. No. 14/871,050 (Docket No DHP0115 US, filed Sep. 30, 2015, entitled METHOD AND APPARATUS FOR MITIGATING INDUCED SHOCK AND VIBRATION (inventors Christopher Ellis Schroeder, Charles Powell Morris, and Kevin Lee Van Pelt) and pending non-Provisional U.S. application Ser. No. 14/871,173 (Docket No DHP0116 US, filed Sep. 30, 2015, entitled IMPROVED STORAGE DEVICE SLED AND ASSEMBLY METHOD THEREOF (inventors Kevin Lee Van Pelt, Charles Powell Morris, and Christopher Ellis Schroeder). 
     
    
     FIELD 
       [0002]    The present invention is directed to computer data storage. In particular, the present invention is directed to improved storage device sleds with self-biasing features for mounting data storage devices in storage enclosures. 
       BACKGROUND 
       [0003]    Storage subsystems provide system mass storage incorporating many storage devices. Storage devices usually include hard disk drives, but may include solid-state drives, optical drives, or tape drives. Storage subsystems include within a single storage chassis one or more storage devices, power supplies, and possibly one or more storage controllers, including Redundant Array of inexpensive disks (RAID) controllers. 
         [0004]    In order to provide non-stop operation, redundant controllers, power supplies, and/or storage devices are often provided in the storage subsystem. Additionally, such assemblies are generally provided as field replaceable modules or FRUs. Field replaceable modules are packaged individually, in order to facilitate removal and replacement of individual controllers, power supplies, or storage devices. Additionally, such modules are often hot replaceable, and able to be replaced while the storage subsystem is powered up and even actively conducting I/O operations to one or more storage devices. Individual storage devices are commonly packaged within a storage device module consisting of a plastic or sheet metal tray for mounting the storage device and a front bezel incorporating a latching mechanism, and in some cases visual indicators. 
         [0005]    Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The oscillations may be periodic such as the motion of a pendulum or random such as the movement of a tire on a gravel road. Storage enclosures often include spinning devices such as fans or hard disk drives that generate vibrations related to rotation speed and how well motors are balanced. Storage enclosures may additionally be subject to shock events such as when a storage enclosure is dropped onto a hard surface or an outside force strikes the storage enclosure. Both vibration and shock may be transferred at least in part to operating storage devices, resulting in loss of performance and possibly degrading long-term reliability. 
       SUMMARY 
       [0006]    The present invention is directed to solving disadvantages of the prior art. In accordance with embodiments of the present invention, a self-biasing storage device sled for mounting a storage device within a chassis is provided. The self-biasing storage device sled includes a bezel forming a front surface of the storage device sled. The bezel includes a first portion that is stationary relative to a storage device mounted within the storage device sled, a second portion vertically captured within the first portion and configured to slide transversely between an unlatching and a latching position, and a spring retained between the bezel first and second portions and configured to push the latch outwardly from the bezel. The second portion includes a finger-movable member, a latch configured to engage a matching opening in a first chassis interior side surface when the storage device sled is installed in the chassis, and a horizontal biasing feature adjacent to the latch and configured to move in concert with the latch. When the storage device is mounted to the storage device sled and installed in the chassis, the horizontal biasing feature exerts force against the first chassis interior side surface and biases the storage device sled against a second chassis interior side surface, where the second chassis interior side surface is on an opposite side of the storage device from the first chassis interior side surface. 
         [0007]    In accordance with another embodiment of the present invention, a method for removing a self-biasing storage device sled from a chassis is provided. The method includes moving, by a finger, a finger-movable member of a second portion of a storage device sled bezel horizontally toward the center of a first portion of the storage device sled bezel, where the second portion is vertically captured within the first portion and is configured to slide transversely between an unlatching and a latching position. The second portion includes a latch, configured to engage a matching opening in a first chassis interior side surface when the storage device sled is installed in the chassis, and a horizontal biasing feature adjacent to the latch and configured to move in concert with the latch. The method also includes unloading, by the second portion, the horizontal biasing feature away from the first interior side surface of the chassis, where the horizontal biasing feature does not exert force against chassis interior side surfaces when unloaded. The method further includes unlatching, by the second portion, the latch from the matching opening in the first chassis interior side surface and pulling the storage device sled from the chassis. 
         [0008]    An advantage of the present invention is it provides a storage device sled that includes both vertical and horizontal integral self-biasing features to self-bias a mounted storage device within a storage enclosure. The mounted storage device includes a storage device securely mounted to the storage device sled. The self-biasing features load the mounted storage device under spring pressure within the chassis and minimize adverse affects due to induced shock and vibration. 
         [0009]    Another advantage of the present invention is that the self-biasing features are integral to the storage device sled longitudinal and latching members. Therefore, additional components are not required to provide the self-biasing features, and the advantages of a self-biasing storage device sled can be advantageously provided relative to a non-biased storage device sled. 
         [0010]    Additional features and advantages of embodiments of the present invention will become more readily apparent from the following description, particularly when taken together with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a block diagram illustrating components of a data storage network in accordance with embodiments of the present invention. 
           [0012]      FIG. 2 a    is a block diagram illustrating components of a host-based or expansion data storage system in accordance with embodiments of the present invention. 
           [0013]      FIG. 2 b    is a block diagram illustrating components of a non host-based data storage system in accordance with embodiments of the present invention. 
           [0014]      FIG. 3 a    is a diagram illustrating an isometric view of a storage enclosure with a drawer extended in accordance with a first embodiment of the present invention. 
           [0015]      FIG. 3 b    is a diagram illustrating an isometric view of a storage device mounted in a drawer in accordance with a first embodiment of the present invention. 
           [0016]      FIG. 3 c    is a diagram illustrating an isometric view of a conventional mounted storage device in accordance with a first embodiment of the conventional art. 
           [0017]      FIG. 3 d    is a diagram illustrating an exploded isometric view of a conventional mounted storage device in accordance with a first embodiment of the conventional art. 
           [0018]      FIG. 4 a    is a diagram illustrating an isometric view of a storage enclosure with a mounted storage device removed in accordance with a second embodiment of the present invention. 
           [0019]      FIG. 4 b    is a diagram illustrating an isometric view of a conventional mounted storage device in accordance with a second embodiment of the conventional art. 
           [0020]      FIG. 4 c    is a diagram illustrating an exploded isometric view of a conventional mounted storage device in accordance with a second embodiment of the conventional art. 
           [0021]      FIG. 5 a    is a diagram illustrating an isometric view of an improved mounted storage device in accordance with a first embodiment of the present invention. 
           [0022]      FIG. 5 b    is a diagram illustrating an exploded isometric view of an improved mounted storage device in accordance with a first embodiment of the present invention. 
           [0023]      FIG. 5 c    is a diagram illustrating a bottom rear isometric view of an improved storage device sled in accordance with a first embodiment of the present invention. 
           [0024]      FIG. 5 d    is a diagram illustrating a side view of an improved mounted storage device in accordance with a first embodiment of the present invention. 
           [0025]      FIG. 5 e    is a diagram illustrating a detail view of an improved mounted storage device in accordance with a first embodiment of the present invention. 
           [0026]      FIG. 5 f    is a diagram illustrating a top view of a clip and latch arrangement of an improved storage device sled in accordance with a first embodiment of the present invention. 
           [0027]      FIG. 5 g    is a diagram illustrating a detail view of a clip and latch arrangement of an improved storage device sled in accordance with a first embodiment of the present invention. 
           [0028]      FIG. 6 a    is a diagram illustrating a first step of an assembly sequence for an improved mounted storage device in accordance with a first embodiment of the present invention. 
           [0029]      FIG. 6 b    is a diagram illustrating a second step of an assembly sequence for an improved mounted storage device in accordance with a first embodiment of the present invention. 
           [0030]      FIG. 6 c    is a diagram illustrating a third step of an assembly sequence for an improved mounted storage device in accordance with a first embodiment of the present invention. 
           [0031]      FIG. 7 a    is a diagram illustrating an isometric view of an improved mounted storage device in accordance with a second embodiment of the present invention. 
           [0032]      FIG. 7 b    is a diagram illustrating an exploded isometric view of an improved mounted storage device in accordance with a second embodiment of the present invention. 
           [0033]      FIG. 7 c    is a diagram illustrating a side view of an improved mounted storage device in accordance with a second embodiment of the present invention. 
           [0034]      FIG. 7 d    is a diagram illustrating a detail view of an improved mounted storage device in accordance with a second embodiment of the present invention. 
           [0035]      FIG. 8 a    is a diagram illustrating an untreated shock response in accordance with embodiments of the present invention. 
           [0036]      FIG. 8 b    is a diagram illustrating a treated shock response in accordance with embodiments of the present invention. 
           [0037]      FIG. 9 a    is a diagram illustrating an untreated vibration response in accordance with embodiments of the present invention. 
           [0038]      FIG. 9 b    is a diagram illustrating storage device I/O performance over a predetermined frequency range in accordance with embodiments of the present invention. 
           [0039]      FIG. 9 c    is a diagram illustrating a treated damped vibration response in accordance with embodiments of the conventional art. 
           [0040]      FIG. 9 d    is a diagram illustrating a treated vibration response by reducing response frequencies in accordance with embodiments of the present invention. 
           [0041]      FIG. 9 e    is a diagram illustrating desired post-treatment I/O performance response according to embodiments of the present invention. 
           [0042]      FIG. 9 f    is an illustration of insufficient correction of I/O performance according to embodiments of the present invention. 
           [0043]      FIG. 10  is a block diagram illustrating a resonant frequency determination configuration in accordance with embodiments of the present invention. 
           [0044]      FIG. 11  is a block diagram illustrating a shock and vibration evaluation configuration in accordance with embodiments of the present invention. 
           [0045]      FIG. 12  is a flowchart illustrating a storage device shock optimization process in accordance with the preferred embodiment of the present invention. 
           [0046]      FIG. 13  is a flowchart illustrating a storage device vibration optimization process in accordance with the preferred embodiment of the present invention. 
           [0047]      FIG. 14  is a flowchart illustrating a process to determine a frequency or frequencies of concern for a storage device in accordance with the preferred embodiment of the present invention. 
           [0048]      FIG. 15  is a flowchart illustrating a process to establish resonant frequencies of storage devices in accordance with the preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0049]    The present invention is directed to the problem of reducing induced shock and vibration to storage devices in storage enclosures. Referring now to  FIG. 1 , a block diagram illustrating components of a data storage network  100  in accordance with embodiments of the present invention is shown. Data storage network  100  provides interconnection between one or more host computers  108  and one or more storage enclosures  112 . Network  104  includes networking communication technologies suitable for high-volume data transfers between host computers  108  and storage enclosures  112 . Such technologies include Fiber Channel, Ethernet, SSA, SAS, iSCSI, Infiniband, ESCON, and FICON. Network  104  includes, but is not limited to local area networks (LANs), storage area networks (SANs), and cellular communication networks. 
         [0050]    Host computers  108  execute application programs, and communicate with other host computers  108  or storage enclosures  112  through network  104 . Storage enclosures  112  include storage devices that provide mass data storage. Storage devices include hard disk drives, tape drives, optical drives, and solid state drives. In some embodiments, data storage network  100  includes one or more management computers  116 . Management computers  116  monitor network  104 , and provide error monitoring, configuration, and control functions. In most embodiments, management computer  116  includes a graphical user interface (GUI)  120 , through which users or system administrators interact with management computer  116 . In some embodiments, management computer  116  interfaces with storage enclosures  112  through network  104 . In other embodiments, management computer  116  interfaces with storage enclosures  112  through a different connection or network other than network  104 . Although three host computers  108   a ,  108   b ,  108   c  and three storage enclosures,  112   a ,  112   b ,  112   c  are shown in  FIG. 1 , network  104  includes any number of host computers  108  and storage enclosures  112 . 
         [0051]    Referring now to  FIG. 2 a   , a block diagram illustrating components of a host-based or expansion data storage system  200  in accordance with embodiments of the present invention is shown. 
         [0052]    The data storage system  200  includes one or more host computers  108 . Host computer  108  is generally a server, but could also be a desktop or mobile computer. Host computer  108  executes application programs that generate read and write requests to a storage controller  204  within the host computer  108 . In some embodiments, storage controller  204  is a host bus adapter or storage controller card in host computer  108 . In other embodiments, storage controller  204  is a combination of an I/O controller often on a motherboard of host computer  108  and software applications running on one or more processors of host computer  108 . Storage controller  204  communicates with storage devices  208  in a drawer  212  of JBOD storage enclosure  112  over host bus or network  104 . Host bus or network  104  in one embodiment is a bus such as SCSI, FC-AL, USB, Firewire, SSA, SAS, SATA, or Infiniband. In another embodiment, host bus or network  104  is a network such as Ethernet, iSCSI, Fiber Channel, SSA, ESCON, ATM, FICON, or Infiniband. 
         [0053]    Host computer  108  interfaces with one or more storage controllers  204 , although only a single storage controller  204  is illustrated for clarity. In one embodiment, storage controller  204  is a RAID controller. In another embodiment, storage controller  204  is a storage appliance such as a provisioning, virtualization, replication, or backup appliance. Storage controller  204  transfers data to and from storage devices  208   a - 208   z  in drawer  212  of JBOD storage enclosure  112 . 
         [0054]    JBOD Storage enclosure  112  in one embodiment contains 48 storage devices  208 , with 16 storage devices  208  in each of three drawers  212 . In other embodiments, JBOD Storage enclosure  112  may contain fewer or more than 48 storage devices  208 , or include all storage devices  208  in a single chassis without drawers  212 . Storage devices  208  include various types of storage devices, including hard disk drives, solid state drives, optical drives, and tape drives. Within a specific storage device  208  type, there may be several sub-categories of storage devices  208 , organized according to performance. For example, hard disk drives may be organized according to cache size, drive RPM (5,400, 7,200, 10,000, and 15,000, for example), queue depth, random transfer rate, or sequential transfer rate. 
         [0055]    Referring now to  FIG. 2 b   , a block diagram illustrating components of a non host-based data storage system  216  in accordance with embodiments of the present invention is shown. Non host-based data storage system  216  is similar to host-based or expansion data storage system  200 , with the exception being storage controller  204  is within storage enclosure  112 , along with storage devices  208 . In the embodiment illustrated in  FIG. 2 b   , storage controller  204  is a single RAID controller  204 . However, in other embodiments, storage controller  204  represents multiple RAID or other storage controllers  204  discussed with respect to  FIG. 2   a.    
         [0056]    Referring now to  FIG. 3 a   , a diagram illustrating an isometric view of a storage enclosure  112   a  with a drawer  212  extended in accordance with a first embodiment of the present invention is shown. Storage enclosure  112   a  includes a plurality of drawers  212 , each of which stores a plurality of mounted storage devices  308 ,  508  in a chassis  304 . Chassis  304  also includes one or more power supplies, and in some embodiments, one or more storage controllers  204 . In the embodiment illustrated, each drawer  212  stores up to 16 mounted storage devices  308 ,  508 , where all storage devices  208  have a 2.5 inch form factor. However, the present invention is not limited to any number of drawers  212 , mounted storage devices  308 ,  508 , or storage devices  208 . 
         [0057]    Referring now to  FIG. 3 b   , a diagram illustrating an isometric view of a storage device  208  mounted in a drawer  212  in accordance with a first embodiment of the present invention is shown. It is generally assumed that all drawers  212  have a similar general configuration, and store the same number of mounted storage devices  308 ,  508 . 
         [0058]    Each mounted storage device  308 ,  508  is individually removable and insertable from drawer  212 . This allows rapid replacement of a failed storage device  208  with a spare or otherwise working storage device  208 . Each mounted storage device  308 ,  508  therefore includes a rail system to slide the mounted storage device  308 ,  508  into the drawer  212 , as well as a means to latch each mounted storage device  308 ,  508  into the chassis  304  or drawer  212 . 
         [0059]    Mounted storage devices  308 ,  508  include a finger-actuated latching mechanism to allow a latch of the mounted storage device  308 ,  508  to engage a matching opening  320  in a first chassis interior side surface  312 . In most cases, only a single latch is provided in each mounted storage device  308 ,  508 . Correspondingly, the drawer  212  has a second chassis interior side surface  316  opposite the first chassis interior side surface  312  that lacks a matching opening  320  or other latch receiving feature. In storage enclosures  112   a  of the first embodiment, each drawer  212  must be extended from the chassis  304  in order to insert or remove mounted storage devices  308 ,  508 . 
         [0060]    Referring now to  FIG. 3 c   , a diagram illustrating an isometric view of a conventional mounted storage device  308  in accordance with a first embodiment of the conventional art is shown. The conventional mounted storage device  308  does not include primary features of the present invention, and instead represents conventional features intended to mitigate the effect of shock and vibration events to storage devices  208 . 
         [0061]    The conventional mounted storage device  308  provides a sliding rail system and other features mounted to a storage device  208  to allow storage device  208  to be individually inserted or removed from a chassis  304  or drawer  212 . One half of the conventional mounted storage device  308  is a non-latching side of a storage device sled  324 , and the other half of the conventional mounted storage device  308  is a latching side of a storage device sled  328 . The latching side of the storage device sled  328  includes an integral latch  336  that moves relative to the matching opening  320  when the finger grabs  332  are pinched together. The conventional mounted storage device  308  includes shock and vibration absorbing features in the form of elastomeric overmold around mounting holes  340 . The elastomeric overmold  340  is formed over side member material, and is generally rubber or an elastic polymer. Although the elastomer overmold around mounting holes  340  is effective for shock and vibration mitigation, applying the overmold  340  adds cost to the mounted storage device  308  by requiring additional manufacturing processes and material. It is desirable to provide shock and vibration mitigation in a mounted storage device  308  without requiring different materials or manufacturing steps to apply the different materials. 
         [0062]    Referring now to  FIG. 3 d   , a diagram illustrating an exploded isometric view of a conventional mounted storage device  308  in accordance with a first embodiment of the conventional art is shown. Conventional mounted storage device  308  includes two halves, each mounted to a side of storage device  208  through threaded fasteners  344 . 
         [0063]    The latching side of the storage device sled  328  deflects under finger pressure relative to the non-latching side of the storage device sled  324 , which allows a latch in the side of the latching side of the storage device sled  328  to disengage from the matching opening  320 . The threaded fasteners  344  engage mounting holes in the side of the storage device  208 , and the elastomer overmold around the mounting holes  340  mechanically isolates each of the threaded fasteners  344  from the storage device sled  324 ,  328 . 
         [0064]    Referring now to  FIG. 4 a   , a diagram illustrating an isometric view of a storage enclosure  112   b  with a mounted storage device  408 ,  708  removed in accordance with a second embodiment of the present invention is shown. In the second embodiment, mounted storage devices  408   708  are directly inserted or removed from a chassis  404 , and individual storage device drawers  212  are not present. In the embodiment illustrated in  FIG. 4 a   , the storage devices  208  are all 3.5″ in form factor. In general, mounted storage devices  308 ,  408 ,  508 ,  708  are all hot pluggable into a back planar midplane within a chassis  304 ,  404  or drawer  212 . 
         [0065]    Referring now to  FIG. 4 b   , a diagram illustrating an isometric view of a conventional mounted storage device  408  in accordance with a second embodiment of the conventional art is shown. The conventional mounted storage device  408  does not include the shock and vibration mitigation features of the present invention, and instead represents conventional features intended to mitigate the effect of shock and vibration events to storage devices  208 . 
         [0066]    The conventional mounted storage device  408  provides a sliding rail system and other features mounted to a storage device  208  to allow storage device  208  to be individually inserted or removed from the chassis  404 . The conventional mounted storage device  408  includes a storage device sled bezel  412  mounted across the front of a storage device sled, with side pieces extending rearward that physically mount to the sides of storage device  208 . The storage device sled bezel  412  includes a finger movable member  416  coupled to a latch  420  that engages the matching opening  320  in the side of the chassis  404 . The conventional mounted storage device  408  includes shock and vibration absorbing features in the form of elastomeric overmold around mounting holes  420 . The elastomeric overmold  420  is formed over side member material, and is generally rubber or an elastic polymer. Although the elastomer overmold around mounting holes  420  is effective for shock and vibration mitigation, applying the overmold  420  adds cost to the mounted storage device  408  by requiring additional manufacturing processes and material. It is desirable to provide shock and vibration mitigation in a mounted storage device  408  without requiring different materials or manufacturing steps to apply the different materials. 
         [0067]    Referring now to  FIG. 4 c   , a diagram illustrating an exploded isometric view of a conventional mounted storage device  408  in accordance with a second embodiment of the conventional art is shown. The conventional mounted storage device  408  includes a storage device  208  mounted to a storage device sled by a plurality of threaded fasteners  344 . In most cases, the threaded fasteners  344  are conventional sheet metal screws. Each of the threaded fasteners  344  engages a different mounting hole on the sides of the storage device  208 , through an elastomer overmold around mounting holes  424 . 
         [0068]    Referring now to  FIG. 5 a   , a diagram illustrating an isometric view of an improved mounted storage device  508  in accordance with a first embodiment of the present invention is shown. The improved mounted storage device  508  is able to mount within the same drawer  212  or chassis  304  is the conventional mounted storage device  308 . Additionally, the storage device sled includes a non-latching side bezel member  512  as well as a latching side bezel member  516 . 
         [0069]    However, a key difference between the improved mounted storage device  508  and the conventional mounted storage device  308  involves the attachment area of the storage device sled around the holes through which threaded fasteners  344  are coupled to the sides of storage device  208 . Instead of an elastomer overmold around the mounting holes  340 , the improved mounted storage device  508  includes no elastomer compound or other material separate from the side rails of the storage device sled to provide shock or vibration reduction to the storage device  208 . Rather, the area around the holes has an altered structural stiffness  504  compared to an unmodified storage device sled. The area of altered structural stiffness  504  will be discussed in more detail with respect to  FIG. 5   e.    
         [0070]    Referring now to  FIG. 5 b   , a diagram illustrating an exploded isometric view of an improved mounted storage device  508  in accordance with a first embodiment of the present invention is shown. The improved mounted storage device  508  includes a non-latching side bezel member  512  coupled to a longitudinal member  532   a  extending rearward toward a hot pluggable midplane or backplane in the drawer  212  or chassis  304 . The non-latching side bezel member  512  is a stationary member  536 , and does not move relative to the storage device  208 . A threaded fastener  344  attaches longitudinal member  532   a  to a mounting hole of storage device  208 . 
         [0071]    The improved mounted storage device  508  also includes a latching side bezel member  516  coupled to a longitudinal member  532   b  extending rearward toward the hot pluggable midplane or backplane in the drawer  212  or chassis  304 . The latching side bezel member  516  includes a finger movable member  520  coupled to a latch  524 . Therefore, when the finger movable member  520  is moved toward the stationary member  536 , the latch  524  is retracted within the latching side bezel member  516  and does not retain the improved mounted storage device  508  within the drawer  212  or chassis  304 . Another threaded fastener  344  attaches longitudinal member  532   b  to another mounting hole of storage device  208 . 
         [0072]    One bezel member  512 ,  516  includes a latching clip  528 , which engages a latching clip receiver in the other bezel member  512 ,  516 . The latching clip  528  maintains a positive connection between the non-latching side bezel member  512  and the latching side bezel member  516 , independent of the finger movable member  520 . 
         [0073]    Additionally, one bezel member  512 ,  516  includes alignment projections  540  which extend toward the other bezel member  512 ,  516  and engage cutouts  544  in the other bezel member  512 ,  516  to align the non-latching side bezel member  512  with the latching side bezel member  516 . It should be noted that the latching clip  528 , latching clip receiver, alignment projections  540 , and cutouts  544  may be located on either bezel member  512 ,  516  as long as there is a complementary registration in the other bezel member  512 ,  516 . That is, the latching clip  528  and latching clip receiver provide complementary registration, and the alignment projections  540  and cutouts  544  provide complementary registration. 
         [0074]    In order to minimize manufacturing cost, longitudinal member  532   a  and the non-latching side bezel member  512  are a single piece of material. Similarly, longitudinal member  532   b  and the latching side bezel member  516  (but excluding the finger-movable member  520  and latch  524 ) are also a single piece of material. In the preferred embodiment, the material for both pieces is an injection molded polymer such as ABS or PCABS plastic. 
         [0075]    Referring now to  FIG. 5 c   , a diagram illustrating a bottom rear isometric view of an improved storage device sled in accordance with a first embodiment of the present invention is shown. The improved mounted storage device  508  includes a storage device  208  mounted within the improved storage device sled. 
         [0076]    As described previously with reference to  FIG. 5 c   , one of bezel members  512 ,  516  includes a latching clip receiver  548  which retains latching clip  528  and keeps non-latching side bezel member  512  coupled to latching side bezel member  516 . The latching clip  528  is oriented in a fashion that prevents the non-latching side of bezel member  512  from being separated from the latching side of bezel member when longitudinal member  532   a  is parallel to longitudinal member  532   b . Instead, when the distal end of longitudinal member  532   a  is pulled away from the distal end of longitudinal member  532   b , latching clip  528  separates from latching clip receiver  548  and the non-latching side bezel member  512  may then be separated from the latching side bezel member  516 . 
         [0077]    The improved mounted storage device  508  also includes one or more tapered posts  552  on the inside of each longitudinal member  532   a ,  532   b . The tapered posts  552  substitute for threaded fasteners  344 , and reduce the number of threaded fasteners  344  and assembly time required to mount the storage device  208  in the improved storage device sled. The function and operation of the tapered posts  552  is discussed in more detail with respect to  FIGS. 6 a -6 c   . It is generally preferred, but not required, that the tapered posts  552  have a slight interference fit with the storage device mounting holes  604 . 
         [0078]    Referring now to  FIG. 5 d   , a diagram illustrating a side view of an improved mounted storage device  508  in accordance with a first embodiment of the present invention is shown. Although longitudinal member  532   b  is illustrated, each of the longitudinal members  532   a ,  532   b  includes a front vertical biasing feature  560   a  and a rear vertical biasing feature  560   b . The front vertical biasing feature  560   a  is formed from the same material as longitudinal members  532   a ,  532   b  and is oriented toward the front end of improved mounted storage device  508 . The front vertical biasing feature  560   a  exerts spring force against a drawer  212  or chassis  304  surface directly above the mounted storage device  508 , and therefore biases a bottom surface of the improved mounted storage device  508  against an adjacent planar surface of the drawer  212  or chassis  304 . In this way, the front portion of the improved mounted storage device  508  is securely held in place within the drawer  212  or chassis  304  and is not free to move in response to shock or vibration events exposed to storage enclosure  112 . 
         [0079]    Similarly, the rear vertical biasing feature  560   b  is also formed from the same material as longitudinal members  532   a ,  532   b  and is oriented toward the rear of improved mounted storage device  508 . The rear vertical biasing feature  560   b  exerts spring force against a drawer  212  or chassis  304  surface directly above the mounted storage device  508 , and therefore biases a bottom surface of the improved mounted storage device  508  against an adjacent planar surface of the drawer  212  or chassis  304 . In this way, the rear portion of the improved mounted storage device  508  is securely held in place within the drawer  212  or chassis  304  and is not free to move in response to shock or vibration events exposed to storage enclosure  112 . At least one vertical biasing feature  560   a ,  560   b  does not exert biasing force against a chassis  304 ,  404  interior surface until the storage device sled is inserted at least halfway into the chassis  304 ,  404 . Each of the front and rear vertical biasing features  560   a ,  560   b  exerts similar biasing forces against the chassis interior surface when the storage device sled is fully installed in the chassis  304 ,  404 . In another embodiment, at least one of the front vertical biasing feature  560   a  or the rear vertical biasing feature  560   b  is located on the bottom surface of the storage device sled. In yet another embodiment, each of the top and bottom surfaces of the storage device sled includes at least one vertical biasing feature  560 . 
         [0080]    The latching side bezel member  516  includes the latch  524  as well as a horizontal biasing feature  556 . In the preferred embodiment, the horizontal biasing feature  556  is formed as a step of the latch  524  and is formed from the same material as the latch  524 . The latch  524  engages the matching opening  320  in order to secure the mounted storage device  508  within the drawer  212  or chassis  304 . However, the horizontal biasing feature  556  does not engage the matching opening  320  and instead bears against the first chassis interior side surface  312  to bias the improved mounted storage device  508  against the second chassis interior side surface  316 . In this way, the improved mounted storage device  508  does not freely move horizontally in response to shock or vibration events exposed to the storage enclosure  112 . 
         [0081]    The combination of the horizontal biasing feature  556  and front and rear vertical biasing features  560   a ,  560   b  on each of the longitudinal members  532   a ,  532   b  thus secures and locates the improved mounted storage device  508  within the drawer  212  or chassis  304 ,  404  and reduces susceptibility of the storage device  208  to storage enclosure  112  shock and vibration events. 
         [0082]    Referring now to  FIG. 5 e   , a diagram illustrating a detail view of an improved mounted storage device  508  in accordance with a first embodiment of the present invention is shown. The detail view illustrates the area around each threaded fastener  344  of each longitudinal member  532   a ,  532   b.    
         [0083]    Improved shock and vibration performance is achieved by altering material in proximity to each of the threaded fastener  344  holes in each longitudinal member  532   a ,  532   b . Specifically, perforations  564  are placed approximately symmetrically around the threaded fastener  344  holes in order to reduce material stiffness at each threaded fastener  344 . The perforations  564  affect shock and vibration response, and are described in more detail with respect to  FIGS. 8 a -9 f   . It should be noted that the perforations  564  may be simple holes, slotted holes as shown in  FIG. 5 e   , S-shaped slots, or other arrangements. The reduction in stiffness is determined by the area of the perforations  564  compared to the non-perforated areas  568  the same radial distance from the threaded fastener  344  hole. The perforations  564  eliminate the need for elastomer overmold around the mounting holes  340 , and since the perforations  564  may be part of a stamping or injection molding or other forming process (depending on the material) used to form longitudinal members  532   a ,  532   b  there is no need for a secondary overmold process or elastomeric bumpers which adds cost to conventional mounted storage devices  308 . 
         [0084]    Referring now to  FIG. 5 f   , a diagram illustrating a top view of a clip and latch arrangement of an improved storage device sled in accordance with a first embodiment of the present invention is shown. The improved mounted storage device  508  includes a non-latching side bezel member  512  and a latching side bezel member  516 . The latch  524  has a corresponding adjacent horizontal biasing feature  556  which does not extend as far outward as the distal end of latch  524 . 
         [0085]    The latching side bezel member  516  includes a spring  572 , which exerts force between the latching side bezel member  516  and the finger movable member  520  to bias the latch  524  and horizontal biasing feature  556  against the first chassis interior side surface  312 . In the preferred embodiment, the spring  572  is normally in compression, and travel limits between the finger movable member  520  in the latching side bezel member  516  prevent over compression and yield of the spring  572 . In the preferred embodiment, the spring  572  has a wire diameter of 0.024 in and a spring rate of 28.3+/−2.83 lbs/in. (4.95 N/mm). When installed in the latching side bezel member  516 , the spring  572  is normally compressed approximately 0.5 mm. 
         [0086]    Referring now to  FIG. 5 g   , a diagram illustrating a detail view  576  of a clip and latch arrangement of an improved storage device sled in accordance with a first embodiment of the present invention is shown. The latching clip  528  secures the non-latching side bezel member  512  to the latching side bezel member  516 . 
         [0087]    When the improved mounted storage device  508  is latched within a drawer  212  or chassis  304  and it is desired to remove the improved mounted storage device  508 , a user or human operator moves the finger movable member  520  toward the stationary member  536 . Since the finger movable member  520  is preferably formed from the same material as the latch  524  and the horizontal biasing feature  556 , movement of the finger movable member  520  causes both the latch  524  and the horizontal biasing feature  5562  move in the same direction by the same amount. This in turn causes the latch  524  to disengage from the matching opening  320 , thus allowing a user or human operator to pull the complete improved mounted storage device  508  from the drawer  212  or chassis  304 . When the finger movable member  520  is released, the compressed spring  572  then moves the finger movable member  520  away from the stationary member  536  and the latch  524  and horizontal biasing feature  556  again extend fully outward from the latching side bezel member  516 . 
         [0088]    Referring now to  FIG. 6 a   , a diagram illustrating a first step of an assembly sequence for an improved mounted storage device  508  in accordance with a first embodiment of the present invention is shown. Prior to assembly, the components of the improved mounted storage device  508  include a storage device  208 , a non-latching side bezel member  512 , a latching side bezel member  516 , and two threaded fasteners  344 . 
         [0089]    In the first step of assembly, the storage device  208  is tilted upward while a first tapered post  552  engages a forward mounting hole  604  of the storage device  208 . Next, the latching side of the bezel member  516  engages the storage device  208  and the non-latching side bezel member  512  at three points: at a tapered post  552  of the latching side bezel member  516  engaging a forward mounting hole  604  of the storage device  208 , at alignment projections  540  engaging cutouts  544 , and at the latching clip  528  engaging the latching clip receiver  548 . At the conclusion of this first step, the latching side bezel member  516  will be joined to the non-latching side bezel member  512 , and the front tapered posts  552  will engage front mounting holes  604  in the sides of the storage device  208 . 
         [0090]    Referring now to  FIG. 6 b   , a diagram illustrating a second step of an assembly sequence for an improved mounted storage device  508  in accordance with a first embodiment of the present invention is shown. At the second step, the latching clip engages the latching clip receiver  612 , the alignment projections engage the cutouts  616 , and the storage device pivots around the tapered posts  620  such that the storage device is now coplanar with the non-latching side bezel member  512 , the latching side bezel member  516 , and both longitudinal members  532   a ,  532   b.    
         [0091]    Referring now to  FIG. 6 c   , a diagram illustrating a third step of an assembly sequence for an improved mounted storage device  508  in accordance with a first embodiment of the present invention is shown. The final assembly step for improved mounted storage device  508  is to attach threaded fasteners  344  through each of the longitudinal members  532   a ,  532   b . On one side, a threaded fastener  344  screws into a storage device mounting hole  624   a . On the other side, a threaded fastener  344  screws into a storage device mounting hole on the opposite side  624   b.    
         [0092]    Disassembling the improved mounted storage device  508  is essentially the opposite of the steps illustrated in  FIGS. 6 a -6 c   . The only difference is in the final step corresponding to  FIG. 6 a   . Once the storage device  208  is tilted up while pivoting around the tapered posts  552 , the non-latching side bezel member  512  is separated from the latching side bezel member  516  by pulling the distal ends of the longitudinal members  532   a ,  532   b  apart. This causes the latching clip  528  to disengage from the latching clip receiver  548 . 
         [0093]    Referring now to  FIG. 7 a   , a diagram illustrating an isometric view of an improved mounted storage device  708  in accordance with a second embodiment of the present invention is shown. The improved mounted storage device  708  is intended for use in a chassis  404  as illustrated in  FIG. 4 a   . The front portion of the improved mounted storage device  708  is generally similar to the front portion of the conventional mounted storage device  408 . However, the improved mounted storage device  708  does not include the elastomer overmold around mounting holes  424  used in the conventional mounted storage device  408 . Instead, the improved mounted storage device  708  includes mounting holes with affected structural stiffness  704 . 
         [0094]    Referring now to  FIG. 7 b   , a diagram illustrating an exploded isometric view of an improved mounted storage device  708  in accordance with a second embodiment of the present invention is shown. Unlike the improved mounted storage device  508  of the first embodiment, the improved mounted storage device  708  of the second embodiment has more threaded fasteners  344  than the conventional mounted storage device  408 . Although four threaded fasteners  344  are shown, each of which engages storage device mounting holes  712  in the sides of storage device  208 , it should be noted that the second embodiment could just as well have used two threaded fasteners  344  and two tapered posts  552  as the first embodiment shown in  FIGS. 5 a   - 5   g.    
         [0095]    Referring now to  FIG. 7 c   , a diagram illustrating a side view of an improved mounted storage device  708  in accordance with a second embodiment of the present invention is shown. The improved mounted storage device  708  includes a storage device  208  mounted within an improved storage device sled. The improved mounted storage device  708  includes two threaded fasteners  344  in each longitudinal member  716   a ,  716   b . The threaded fasteners  344  secure the improved storage device sled to the storage device  208 . 
         [0096]    Referring now to  FIG. 7 d   , a diagram illustrating a detail view of an improved mounted storage device  708  in accordance with a second embodiment of the present invention is shown. Similar to the improved mounted storage device  508  of the first embodiment, the improved mounted storage device  708  of the second embodiment utilizes areas of reduced stiffness  704  around each of the threaded fasteners  344 . Perforations  724  arranged approximately symmetrically around each threaded fastener  344  are combined with non-perforated areas  720  between the perforations to reduce material stiffness at the hole corresponding to the threaded fastener  344 . The perforations  724  affect shock and vibration response, and are described in more detail with respect to  FIGS. 8 a -9 f   . It should be noted that the perforations  724  may be simple holes, slotted holes as shown in  FIG. 7 d   , S-shaped slots, or other perforation arrangements. 
         [0097]    Referring now to  FIG. 8 a   , a diagram illustrating an untreated shock response in accordance with embodiments of the present invention is shown. Storage enclosures  112  may be exposed to a variety of shock events. For example, a storage enclosure  112  may be dropped, kicked, or impacted by movement of other equipment in proximity to the storage enclosure  112 . When a shock event impacts a storage enclosure  112 , the storage enclosure  112  structure translates components of the shock event to subassemblies, including power supplies, storage controllers  204 , drawers  212 , and mounted storage devices  308 ,  408 ,  508 , and  708 . The storage device sled of a mounted storage device  308 ,  408 ,  508 , and  708  in turn translates components of the shock event to the storage device  208  itself. 
         [0098]    Shock events are characterized by a g force level over a period of time, or shock duration  812   a . Each shock event has a maximum, or peak shock level  804 . After the peak shock level  804 , the shock event is naturally damped by various components and assemblies of the storage enclosure  112  and decays over time. It is important to note that the peak shock level  804  delivered to a storage enclosure  112  may not be the peak shock level  804   a  delivered to a storage device  208 , and it is most important to measure shock events at individual storage devices  208  with accelerometers or similar instrumentation. Storage devices  208  have a maximum allowed operating shock level  808  specified by the manufacturer. The maximum allowed operating shock level  808  is the level above which a storage device  208  may experience unreliable operation or even damage. Therefore, it is important to keep the peak shock level  804   a  presented to a storage device  208  below the maximum allowed operating shock level  808 . It should be noted that some shock events may have a peak shock level  804   a  so high that is impossible to reduce the peak shock level  804   a  below the maximum allowed operating shock level  808 . 
         [0099]    Referring now to  FIG. 8 b   , a diagram illustrating a treated shock response in accordance with embodiments of the present invention is shown. Shock event treatment seeks to reduce the peak shock level  804   b  experienced by the storage device  208  below the maximum allowed operating shock level  808 , while increasing the shock duration  812   b  compared to the shock duration  812   a  of the untreated shock event. Altering the stiffness  504 ,  704  of longitudinal members  532   a / 532   b  or  716   a / 716   b , respectively, in the area of the threaded fasteners  344  may beneficially alter the shock response illustrated in  FIG. 8   b.    
         [0100]    Performance testing of storage devices  208  includes reading and writing known data patterns to the storage device  208 . In general, storage devices  208  may sustain predetermined performance levels under normal conditions based on design parameters of each storage device  208 . For example, a given hard disk drive storage device  208  is able to sustain a given read or write data transfer rate (in megabytes per second, or MB/s) based on many parameters, including data interface characteristics, disk rotation rate, read and write channel performance, and data caching policies. 
         [0101]    When a shock impulse is presented to hard disk drive storage device  208  during testing, the shock impulse duration is commonly about 40 milliseconds (ms) in duration. Some shock impulses may cause host read or write errors to storage devices  208 . By altering the stiffness  504 .  704  of longitudinal members  532   a / 532   b  or  716   a / 716   b , respectively, it is possible to reduce the peak shock level  804   b  below the maximum allowed shock level  808 . When translated to shock testing, the shock impulse is reduced to a shock impulse where host read and write errors no longer occur. 
         [0102]    The techniques of the present invention do not treat shock impulses using conventional damping techniques. Therefore, the shock impulse energy into the storage device  208  is the same before and after treatment, and the area under the shock impulse of  FIG. 8 a    is the same as the area under the shock impulse in  FIG. 8   b.    
         [0103]    Referring now to  FIG. 9 a   , a diagram illustrating an untreated vibration response in accordance with embodiments of the present invention is shown. Mechanical vibration is provided by operating motors in proximity to a storage enclosure  112 . Within a storage enclosure  112 , vibration is provided by disk drive devices, tape drive devices, optical drives, and rotating fans. Outside a storage enclosure  112 , vibration is typically sourced from compressors, fans, generators, and various other HVAC equipment. Unlike shock events, mechanical vibration is periodic in nature and generally constant. 
         [0104]    Various components of a storage enclosure  112 , including storage device sleds, have inherent resonant frequencies  904  depending on the material, mass, and shape of the components. Resonant frequencies  904  illustrated in  FIG. 9 a    are identified as frequencies f 1 , f 2 , f 3 , f 4 , and f 5 . Each of the resonant frequencies f 1 -f 5  has a center vibration frequency (in Hertz, or Hz) as well as a frequency bandwidth. Additionally, each resonant frequency  904  has a corresponding g force associated with it. 
         [0105]    Referring now to  FIG. 9 b   , a diagram illustrating storage device  208  I/O performance over a predetermined frequency range in accordance with embodiments of the present invention is shown. Performance testing is discussed with reference to  FIG. 11 . In the absence of vibration, a maximum performance level  912  is maintained to storage devices  208 . 
         [0106]    While noting the resonant frequencies  904  identified in  FIG. 9 a   , performance testing is performed to identify which of the resonant frequencies  904  produces a drop in performance below the performance threshold  916 . The performance threshold  916  is a predetermined minimum performance level the system is required to support while exposed to a range of vibration frequencies. In the preferred embodiment, the performance threshold is 90% of the maximum performance level  912 . 
         [0107]    In the example of  FIG. 9 b   , there are two resonant frequencies  904  at which performance drops below the performance threshold  916 . These frequencies are known as frequencies of concern  908 , and are identified as frequencies f 3  and f 5 . Performance at frequencies f 1  and f 4  do not produce levels below the performance threshold  916 , and therefore do not require specific treatment. Additionally, performance at resonant frequency  904  f 2  is unaffected and remains at the maximum performance value  912 . 
         [0108]    Referring now to  FIG. 9 c   , a diagram illustrating a treated damped vibration response in accordance with embodiments of the conventional art is shown. Damped vibration frequencies have the characteristic of a reduced g force compared with un-damped vibration frequencies, but a greater vibration frequency bandwidth. Damped treatment generally includes use of softer or elastomeric materials such as rubber bumpers or overmolds located at mechanical coupling points between assemblies. For example the elastomer overmold around mounting holes  340 ,  424  illustrated in  FIGS. 3 c  and 4 b   , respectively, would provide a damped vibration frequency response. Even with a damped treatment, one or more vibration frequencies  924  may exceed a g force threshold  920 . The g force threshold  920  corresponds to a level above which performance degradation by the storage device  208  may be observed. 
         [0109]    Referring now to  FIG. 9 d   , a diagram illustrating a treated vibration response by reducing response frequencies in accordance with embodiments of the present invention is shown. As discussed previously, damped treatments increase costs by requiring additional components and secondary manufacturing operations to add elastomeric materials to rigid components. 
         [0110]    The present invention seeks to mitigate storage device  208  performance problems due to vibration frequencies by lowering the effective resonant frequencies that may cause performance problems. This is achieved by altering the stiffness  504 ,  704  of longitudinal members  532   a / 532   b  or  716   a / 716   b , respectively, in proximity to the holes where threaded fasteners  344  are located. The stiffness may be altered by either increasing the stiffness or by lowering the stiffness. Stiffness may be increased by increasing the thickness of the material in proximity to the threaded fastener  344  mounting holes or by substituting a stiffer material for the longitudinal members  532   a / 532   b  or  716   a / 716   b . Stiffness may be reduced by substituting a less stiff material for the longitudinal members  532   a / 532   b  or  716   a / 716   b , or by relieving or perforating the material  504 ,  704  in proximity to mounting holes used for the threaded fasteners  344 . Substituting a less stiff material may be undesirable due to wear or cost considerations. However, relieving or perforating the material often comes at little to no cost impact since relieving/perforating the material may be easily integrated into injection molds used for polymers or stamping/drilling operations suitable for use with metal materials. The effect of reducing stiffness  344  in proximity to threaded fastener  344  mounting holes is illustrated in  FIG. 9 d   , where the response near the frequencies of concern  928  are reduced below the g force threshold  920 . 
         [0111]    Referring now to  FIG. 9 e   , a post-treatment I/O performance response according to embodiments of the present invention is shown. The I/O performance response shown in  FIG. 9 e    is the desired post-treatment response, in which no dips below the performance threshold  916  are observed across the tested frequency range. Most commonly, the dips that still exist have center frequencies slightly lower than the resonant frequencies  904  due to reducing the material stiffness  504 ,  704  in proximity to the threaded fasteners  344 . 
         [0112]    Referring now to  FIG. 9 f   , an illustration of insufficient correction of I/O performance according to embodiments of the present invention is shown. Once testing has identified frequencies of concern  908  as shown in  FIG. 9 b   , the material stiffness  504 ,  704  in proximity to the threaded fasteners  344  is reduced. After reducing the material stiffness, the mounted storage device  508 ,  708  is retested according to the test configuration described with respect to  FIG. 11 . 
         [0113]    If retesting reveals one or more dips below the performance threshold  916 , additional treatment is required. In the preferred embodiment, the material stiffness in proximity to the storage device sled mounting holes  504 ,  704  is again reduced. Subsequent stiffness reduction corresponding to dip  932  compared with the untreated dip shown in  FIG. 9 b    should be used to guide the amount of material relieved. After further reducing the material stiffness, the mounted storage device  508 ,  708  is retested again until the response resembles the response shown and described in  FIG. 9 e   . If further reduction of material stiffness is not possible or practical, then either conventional damping techniques using elastomeric materials or a change in storage device sled materials or thicknesses may be required. 
         [0114]    Referring now to  FIG. 10 , a block diagram illustrating a resonant frequency  904  determination configuration in accordance with embodiments of the present invention is shown. Different types, brands, and sizes of storage devices  208  have different resonant frequencies  904 . In order to empirically determine the resonant frequencies  904  for a specific storage device  208 , it is necessary to instrument a storage device  208  and observe the response to a vibration profile presented to the storage device  208 . 
         [0115]    A swept sine wave generator  1004  generates a swept sine wave  1008  over a frequency range determined by the operator. Because low frequencies are often resonant frequencies, in most cases the lower limit of the swept sine wave  1008  should be 0 Hz, or DC. The upper range of vibration frequencies for the swept sine wave  1008  depends on the characteristics of the individual storage device  208 . With current hard disk drive technology, approximately 5 kHz is a reasonable upper frequency for the swept sine wave  1008 . However, with track densities increasing every year it should be expected to have upper frequency limits at 10 kHz or even 20 kHz or more. 
         [0116]    Storage device  208  is instrumented with an accelerometer  1012  or other device that reports g forces that may be graphically observed or recorded. Accelerometer  1012  provides accelerometer data  1016  to a display terminal or computer  1020 . The result of the resonant frequency  904  determination testing will be a graph approximately similar to that which is illustrated in  FIG. 9 a   . The graph will identify where the resonant frequencies  904  of the storage device  208  are, and which frequencies are likely to be frequencies of concern  908 . 
         [0117]    Referring now to  FIG. 11 , a block diagram illustrating a shock and vibration evaluation configuration in accordance with embodiments of the present invention is shown. Shock and vibration testing is independently conducted to the storage enclosure  112 , and most of the configuration is the same for either shock or vibration testing. 
         [0118]    Storage enclosure  112  includes one or more mounted storage devices  308 ,  408 ,  508 ,  708 , and an accelerometer  1012  is placed on the specific storage device  208  under test. A computer running a performance test or I/O profiling application  1112  is connected to the storage enclosure  112  through a standard I/O interface that handles read and write requests to the mounted storage devices  308 ,  408 ,  508 ,  708 . The I/O profiling software application  1112  generates read and write I/O requests  1116  to individually addressed storage devices  208 . 
         [0119]    The accelerometer  1012  provides accelerometer data  1016  to a display terminal or computer  1020 . In general, the accelerometer data  1016  includes g forces the storage device  208  under test is exposed to. The display terminal or computer  1020  provides a graphical illustration of the accelerometer data  1016  as either the g force profile and the duration of a shock impulse  1108 , or the g force profile over a range of vibration frequencies provided by a swept sine wave  1008 . In some embodiments, the display terminal or computer  1020  is the same computer running the I/O profiling application  1112 . In other embodiments, the display terminal or computer  1020  is a different computer from the computer running the I/O profiling application  1112 . 
         [0120]    For vibration measurements, a swept sine wave generator  1004  provides a swept sine wave  1008  to the storage enclosure  112 . The storage enclosure  112  translates the swept sine wave  1008  into a specific vibration profile detected by the accelerometer  1012 . It has been found that for current storage devices  208 , a minimum vibration testing range of 100 Hz. to 500 Hz. should be used since the most serious resonant frequency  904  problems occur within that range. In other embodiments, the predetermined range of frequencies may extend above or below 5 kHz. For shock measurements, a shock impulse generator  1104  generates a shock impulse  1108  to the storage enclosure  112 . The storage enclosure  112  then translates the shock impulse  1108  into a specific shock profile detected by the accelerometer  1012  at the storage device  208 . 
         [0121]    Referring now to  FIG. 12 , a flowchart illustrating a storage device  208  shock optimization process in accordance with the preferred embodiment of the present invention is shown. Flow begins at block  1204 . 
         [0122]    At block  1204 , a shock impulse generator  1104  is connected to the storage enclosure  112 . The shock impulse generator  1104  creates shock impulses  1108  and delivers them to the storage enclosure  112 . The shock impulses  1108  have a predetermined g force  804   a  and duration  812   a . Flow continues to block  1208 . 
         [0123]    At block  1208 , a computer running in I/O profiling application  1112  is connected to the storage enclosure  112 . The computer  1112  is connected through an I/O interface to the storage enclosure  112 , where the I/O interface supports a data protocol supported by both the computer  1112  and the storage enclosure  112 . The computer  1112  includes a profiling software application that generates I/O requests  1116  and measures response time or throughput of the I/O requests. The I/O requests include read and write requests  1116 . In some embodiments, the protocol used for the I/O requests  1116  is a block level protocol such as SCSI. In other embodiments the protocol used for the I/O requests  1116  is a file level protocol. Flow continues to block  1212 . 
         [0124]    At block  1212 , the computer  1112  runs the profiling software application which generates I/O requests  1116  to a selected storage device  208 . The computer  1112  measures and records response time and throughput to the I/O requests  1116 . Flow continues to block  1216 . 
         [0125]    At block  1216 , the shock impulse generator  1104  generates predetermined shock impulses  1108  to the storage enclosure  112 . An accelerometer  1012  or other device able to measure shock g forces is attached to the storage device  208  under test. While the shock impulses  1108  are being presented to the storage enclosure  112 , the profiling software application  1112  identifies the shock events and duration, including where there is a drop of more than a predetermined percentage in I/O performance. Flow proceeds to decision block  1220 . 
         [0126]    At decision block  1220 , if there is a drop of more than the predetermined percentage in I/O performance, flow proceeds to block  1224 . If there is not a drop of more than the predetermined percentage in I/O performance  820 , then the administered shock profile is not affecting I/O performance more than a predetermined percentage  820 , and flow instead proceeds to decision block  1228 . 
         [0127]    At block  1224 , the mounting members (longitudinal members  532   a / 532   b  or  716   a / 716   b ) are modified in order to reduce stiffness. In the preferred embodiment, the stiffness is initially reduced by 50% by perforating  504 ,  704  an area around the threaded fasteners  344  mounting holes. It has been found that an initial 50% reduction in stiffness is large enough to produce a meaningful change in performance loss without significantly altering the structural rigidity of the mounting members  532   a / 532   b  or  716   a / 716   b . After the stiffness is initially reduced by 50%, each time block  1224  is executed, in the preferred embodiment the stiffness is reduced by an additional 10% from what it had previously been. In other embodiments, the initial stiffness reduction may be less than 50%, and subsequent stiffness reduction may be less than or more than 10% additional. Flow proceeds to block  1216  to retest the storage device with the new mounting member  532   a / 532   b  or  716   a / 716   b  altered stiffness. 
         [0128]    At decision block  1228 , if there are more untested storage devices  208  in the storage enclosure  112  and it is desirable to test the untested storage devices  208 , flow proceeds to block  1232 . If there are not more untested storage devices  208  in the storage enclosure  112 , or it is not desirable to test the untested storage devices  208 , then flow ends. 
         [0129]    At block  1232 , a next untested storage device  208  is selected. An accelerometer  1012  or appropriate shock instrumentation is attached to the next untested storage device  208 . The profiling software application running on the computer  1112  is modified to address the next untested storage device  208 . Flow proceeds to block  1212  to run the I/O profiling software  1112  to generate I/O requests  1116  to the selected storage device  208 . 
         [0130]    Referring now to  FIG. 13 , a flowchart illustrating a storage device  208  vibration optimization process in accordance with the preferred embodiment of the present invention is shown. Flow begins at block  1304 . 
         [0131]    At block  1304 , the frequency or frequencies of concern  908  are determined. The frequency or frequencies of concern  908  are those frequencies where there is a drop of more than a predetermined percentage in I/O performance  820  of a storage device  208  within the range of a swept sine wave  1008  presented to the storage enclosure  112 . The determination process for the frequency or frequencies of concern  908  is illustrated in more detail in  FIG. 14 . Flow proceeds to block  1308 . 
         [0132]    At block  1308 , the resonant frequencies  904  for the storage devices  208  to be tested are determined. In one embodiment, the manufacturer of the storage devices  208  provides the resonant frequency  904  information. If the manufacturer is unable to provide the resonant frequency  904  information, the resonant frequencies  904  are determined empirically by the process illustrated in  FIG. 15 . The resonant frequencies  904  will validate where the frequencies of concern  908  are, and provides explanations for the frequencies of concern  908  determined in block  1304 . Flow proceeds to decision block  1312 . 
         [0133]    At decision block  1312 , the frequencies of concern  908  are compared to the resonant frequencies  904 . If none of the frequencies of concern  908  correspond to a resonant frequency  904 , then altering the stiffness of a mounting member  532   a / 532   b  or  716   a / 716   b  will not affect the frequencies of concern  908  since the loss of performance at those frequencies  908  is not due to a resonant frequency  904  for the storage device  208  under test. Therefore, if none of the frequencies of concern  908  correspond to a resonant frequency  904 , then flow ends. However, if at least one of the frequencies of concern  908  corresponds to a resonant frequency  904 , then altering the stiffness of a mounting member  532   a / 532   b  or  716   a / 716   b  will affect at least one frequency of concern  908 . In that case, flow proceeds to block  1316 . 
         [0134]    At block  1316 , the mounting members (longitudinal members  532   a / 532   b  or  716   a / 716   b ) are modified in order to reduce performance loss at the frequencies of concern  908 . Performance loss is reduced by reducing the stiffness of the mounting members  532   a / 532   b  or  716   a / 716   b . In the preferred embodiment, the stiffness is initially reduced by 50% by perforating area around the threaded fasteners  344  mounting holes. It has been found that an initial 50% reduction in stiffness is large enough to produce a meaningful change in performance loss without significantly altering the structural rigidity of the mounting members  532   a / 532   b  or  716   a / 716   b . After the stiffness is initially reduced by 50%, each time block  1224  is executed, in the preferred embodiment the stiffness is reduced by an additional 10% from what it had previously been. In other embodiments, the initial stiffness reduction may be less than 50%, and subsequent stiffness reduction may be less than or more than 10% additional. Flow proceeds to decision block  1320 . 
         [0135]    At decision block  1320 , if the initial test or a retest is successful (i.e. no frequencies of concern  908 ), then flow proceeds to block  1324 . If the initial test or a retest is not successful (i.e. at least one frequency of concern  908  remains), then flow proceeds to block  1316  to again modify the mounting members  532   a / 532   b  or  716   a / 716   b  and initiate a retest. 
         [0136]    At block  1324 , the test to the selected storage device  208  is successful. Other storage devices  208  are tested in order to verify reliable operation. Flow proceeds to decision block  1328 . 
         [0137]    At decision block  1328 , if there are problems with the other storage devices  208 , then flow proceeds to block  1304  to reinitiate testing. If there are not problems with the other storage devices  208 , then flow ends. 
         [0138]    Referring now to  FIG. 14 , a flowchart illustrating a process to determine a frequency or frequencies of concern  908  for a storage device  208  in accordance with the preferred embodiment of the present invention is shown. The process illustrated in  FIG. 14  details the steps required to empirically determine the frequency or frequencies of concern  908  at block  1304  of  FIG. 13 . Flow begins at block  1404 . 
         [0139]    At block  1404 , a swept sine wave generator  1004  is connected to the storage enclosure  112 . The swept sine wave generator  1004  imparts a sine wave vibration  1008  to the storage enclosure  112  across a predetermined range of frequencies. In the preferred embodiment, the predetermined range of frequencies is a DC to 5 kHz. It has been found that for current storage devices  208 , a minimum vibration testing range of 100 Hz. to 500 Hz. should be used since the most serious resonant frequency  904  problems occur within that range. In other embodiments, the predetermined range of frequencies may extend above or below 5 kHz. However, it should be noted that newer generations of hard disk drives, for example, have a much higher track density than previous generations of hard disk drives. Therefore, higher vibration frequencies may have increasing effect in inducing off-track read or write failures. It is therefore expected that the upper range of vibration frequencies will increase significantly over future generations of storage devices  208 . Flow proceeds to block  1408 . 
         [0140]    At block  1408 , a computer  1112  is connected to the storage enclosure  112 . The computer  1112  is connected through an I/O interface to the storage enclosure  112 , where the I/O interface supports a protocol supported by both the computer  1112  and the storage enclosure  112 . The computer  1112  includes a profiling software application that generates I/O requests and measures response time or throughput of the I/O requests. The I/O requests include read and write requests  1116 . In some embodiments, protocol is a block level protocol such as SCSI. In other embodiments the protocol is a file level protocol. Flow continues to block  1412 . 
         [0141]    At block  1412 , the computer  1112  runs the profiling software application which generates I/O requests  1116  to a selected storage device  208 . The computer  1112  measures and records response time and throughput to the I/O requests  1116 . Flow continues to block  1416 . 
         [0142]    At block  1416 , the swept sine wave generator  1104  generates a predetermined vibration profile  1008  to the storage enclosure  112  across a range of frequencies. An accelerometer  1012  or other device able to measure shock g forces is attached to the storage device  208  under test. While the vibration profile  1008  is being presented to the storage enclosure  112 , the profiling software application records the I/O performance, including where there is a drop of more than a predetermined percentage in I/O performance  820 . Flow proceeds to decision block  1420 . 
         [0143]    At decision block  1420 , if there are more untested storage devices  208  in the storage enclosure  112 , then flow proceeds to block  1424 . If there are not more untested storage devices  208  in the storage enclosure  112 , then flow ends. 
         [0144]    At block  1424 , a next untested storage device  208  is selected. An accelerometer  1012  or appropriate vibration instrumentation is attached to the next untested storage device  208 . The profiling software application running on the computer  1112  is modified to address the next untested storage device  208 . Flow proceeds to block  1412  to run the I/O profiling software to generate I/O requests  1116  to the next selected storage device  208 . 
         [0145]    Referring now to  FIG. 15 , a flowchart illustrating a process to establish resonant frequencies  904  of storage devices  208  in accordance with the preferred embodiment of the present invention is shown. The process of  FIG. 15  corresponds to block  1308  of  FIG. 13 , and utilizes the block diagram of the resonant frequency determination configuration illustrated in  FIG. 10 . 
         [0146]    At block  1504 , a swept sine wave generator  1004  is connected to the storage device  208 . The swept sine wave generator  1004  generates a swept sine wave  1008  as vibration frequencies to the storage device  208 . Flow proceeds to block  1508 . 
         [0147]    At block  1508 , an accelerometer  1012  is connected to the storage device  208 . The accelerometer  1012  measures g forces imparted by the swept sine wave generator  1004 . Flow proceeds to block  1512 . 
         [0148]    At block  1512 , while altering the swept sine wave  1008  to the storage device  208 , accelerometer data  1016  is presented to a display terminal or computer  1020 . Thus, the display terminal or computer  1020  displays the g forces seen by the storage device  208  across the vibration frequencies  1008 . Flow proceeds to block  1512 . 
         [0149]    At block  1516 , the resonant frequencies  904  are those frequencies where the accelerometer g force  1016  exceeds the input g force  1008  from the swept sine wave generator  1004 . Flow ends at block  1516 . 
         [0150]    Finally, those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiments as a basis for designing or modifying other structures for carrying out the same purposes of the present invention without departing from the spirit and scope of the invention as defined by the appended claims.