Abstract:
An integrated computer module having an EMI shielding plate which doubles as a mechanical retainer for a disk drive within the module and as an shield to insulate the disk drive&#39;s electronics from electromagnetic interference (EMI) emanating from a main PCBA located nearby. The module is adapted for removable insertion into a docking bay within a host assembly, and upon such insertion for connecting to a host connector and thereby controlling a display device. The preferred module comprises an enclosure, a main PCBA in the enclosure including a microprocessor generating EMI; a module connector electrically connected to the main PCBA and supported at the enclosure&#39;s back wall for connection to the host connector upon insertion of the integrated module into the docking bay in the host assembly; a disk drive including a casting and a controller PCBA mounted on one side of the casting; a conductor assembly electrically connecting the main PCBA to the controller PCBA; and an intermediate plate located above the disk drive, between the disk drive&#39;s controller PCBA and the main PCBA, and attached to the enclosure to capture the disk drive in the enclosure and to insulate the controller PCBA from EMI generated by the main PCBA.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates generally to integrated computer modules and, more specifically, to an integrated computer module of compact construction having an intermediate plate which captures a magnetic disk drive in the module and protects the disk drive from electromagnetic interference.  
           [0003]    2. Description of the Related Art  
           [0004]    Today&#39;s personal computers (PC&#39;s) are usually sold in a desktop configuration or a notebook configuration. Desktop PC&#39;s are generally housed in a relatively large chassis containing a main printed circuit board or “motherboard” and other components that are incorporated into or connected to the motherboard. The components may be located inside or outside of the chassis. Typical internal components include a power supply, a central processing unit (CPU), random access memory (RAM), a mass storage device such as a magnetic disk drive, expansion cards connected to a bus on the motherboard, and various peripherals mounted on “rails” in “bays” within the chassis and electrically connected to the motherboard or an associated expansion card by a ribbon cable or the like. Typical expansion cards are a SCSI adapter, a sound adapter, and a network adapter. Typical bay-mounted peripherals are a magnetic disk drive, a floppy drive, a tape drive or a CD-ROM drive. Typical external “peripherals” include user input devices such as a keyboard, a mouse, a microphone, a joystick, a graphics tablet or a scanner) and user output devices such as speakers a printer, and a video display device (e.g. a CRT display or an LCD display). The video adapter that controls the display, as with other adapters, may be integrated into the motherboard or provided on a separate expansion card.  
           [0005]    The users of desktop PC&#39;s may be divided into two divergent groups: (1) experienced users who understand the individual components and tend to frequently upgrade their PC&#39;s by replacing such components, and (2) new users who do not understand or even want to understand the individual components. The latter group may prefer to replace the entire PC, if they upgrade at all. With respect to both groups, however, it has been observed that the need or desire to upgrade occurs far sooner with respect to some components than with respect to other components. In particular, users more frequently upgrade the CPU, the RAM, the magnetic disk drive, and the video adapter. These upgrades tend to provide more capacity and more speed because of rapid technological advancements on the part of manufacturers in response to ever-increasing demands from ever more complicated and more graphics intensive software applications and an associated increase in file sizes. Both user-types less frequently need or desire to upgrade the monitor, the speakers, the keyboard or the power supply, however, because these latter components have withstood the test of time and employ technologies that are less prone to obsolescence.  
           [0006]    These inventors expect that the computer paradigm will move from a large chassis full of individual components of different manufacture toward a readily upgraded system consisting of two primary components: (1) an integrated computer module that compactly houses the frequently upgraded components (e.g. the CPU, the memory, the disk drive, and the video adapter) and provides a module connector for interfacing the module&#39;s electronics with peripherals, and (2) a “host assembly” with a docking bay that receives the module and provides a host connector that mates with the module connector. The host assembly can comprise any “shell” that includes the bay that receives the integrated computer module. The docking bay may be in a host assembly that doubles as a peripheral or in an intermediate assembly that is connected to conventional peripherals. The host assembly, for example, may function and appear generally like a conventional CRT display, save for the addition of the docking bay. A CRT-like host assembly of this nature would also provide a first connector for receiving input from a keyboard and, in all likelihood, a second connector for receiving input from a mouse. As another example, the host assembly may appear like a conventional tower chassis that contains a docking bay for receiving the module, and suitable electronics (e.g. a PCB, cables, and so on) to interface the integrated computer module to conventional expansion cards via an expansion bus, and to conventional peripherals like a display, a keyboard, and a mouse, via connector ports built-in to the host assembly or carried by an expansion card.  
           [0007]    There are a number challenges associated with packing computer components and storage capability into a small integrated computer module. One such challenge is attaching the magnetic disk drive within the module in a secure, cost-effective manner. Another challenge is making sure the analog circuitry associated with the magnetic disk drive, which operates at low voltage levels and is very sensitive to EMI, functions properly in the vicinity of the microprocessor which operates at very high power and at very high clock speeds.  
           [0008]    Computer modules and associated bays have already been proposed. For example, in U.S. Pat. No. 5,463,742 that issued to Kobayashi in 1995, assigned to Hitachi, the inventor discloses a “personal processor module” (PPM) that fits within a notebook type docking station or a desktop type docking station, or simply attaches to a docking housing  6  that is cabled to a keyboard and a monitor. (See FIG. 1). The &#39;742 Patent discloses an embodiment in FIGS. 10 and 11 where a magnetic disk drive and a PCB which carries a microprocessor are situated in a stacked arrangement. The &#39;742 Patent, however, does not show any particular structure for mounting the magnetic disk drive in the PPM, nor does it teach or suggest using an EMI shield between the magnetic disk drive and the PCB.  
           [0009]    In U.S. Pat. No. 5,550,710 that issued in 1996 to Rahamim et al., also assigned to Hitachi, the inventors also disclose a PPM wherein a disk drive and main PCB are stacked. The &#39;710 Patent, however, focuses on a particular cooling structure for a PPM, and also does not disclose any particular structure for mounting the magnetic disk drive in the PPM or for shielding the drive from EMI emanating fom the main PCB.  
           [0010]    There remains a need, therefore, for an integrated computer module with a simple, rugged mechanism for securing the disk drive in the module and for effectively protecting the analog electronics associated with the disk drive from EMI generated by the microprocessor and associated circuitry.  
         SUMMARY OF THE INVENTION  
         [0011]    In a first aspect, the invention may be regarded as an integrated computer module adapted for removable insertion into a docking bay within a host assembly, and upon such insertion for connecting to a host connector and thereby controlling a display device, the integrated computer module comprising: an enclosure defined by a front wall, a back wall opposite the front wall, a first side wall, a second side wall opposite the first guide wall, a floor wall and a ceiling wall; a main printed circuit board assembly (main PCBA) located in the enclosure, the main PCBA including a microprocessor clocked at high frequency and generating electromagnetic interference (EMI); a module connector electrically connected to the main PCBA and supported at the enclosure&#39;s back wall for connection to the host connector upon insertion of the integrated module into the docking bay in the host assembly; a disk drive including a casting and a controller PCBA mounted on one side of the casting, the controller PCBA including integrated circuits that define a hard disk storage control subsystem that operates with relatively low amplitude signals that are subject to distortion from EMI; a conductor assembly electrically connecting the main PCBA to the controller PCBA; and an intermediate plate including a central section, a front edge, a back edge opposite the front edge, a first side edge, and a second side edge opposite the first side edge, the intermediate plate located between the disk drive&#39;s controller PCBA and the main PCBA and attached to the enclosure to capture the disk drive in the enclosure and to protect the controller PCBA from EMI generated by the main PCBA. In the preferred embodiment, the main PCBA and the disk drive are located in a stacked arrangement within the enclosure, with the disk drive&#39;s controller PCBA facing the main PCBA to reduce the length of the conductor assembly and minimize signal degradation 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The just summarized invention may best be understood with reference to the Figures of which:  
         [0013]    [0013]FIG. 1 is a perspective view of an integrated computer module that may be used with a host assembly according to this invention;  
         [0014]    [0014]FIG. 2 is an exploded view of the integrated computer module of FIG. 1;  
         [0015]    [0015]FIG. 2A shows a partially assembled integrated computer module with emphasis on the intermediate plate and its interconnection to the tub;  
         [0016]    [0016]FIG. 2B is an exploded view of the integrated computer module of FIG. 2A;  
         [0017]    [0017]FIG. 3 is a rear view of the integrated computer module of FIG. 1;  
         [0018]    [0018]FIG. 4 is a section view of FIG. 3 taken along section lines  4 - 4 ;  
         [0019]    [0019]FIG. 5 is a rear perspective view of a host assembly that contains a CRT display and is configured to appear like a conventional CRT monitor;  
         [0020]    [0020]FIG. 6 is a front perspective view of a host assembly configured to appear like a conventional tower chassis that may be connected to a monitor, a keyboard, and a mouse (not shown);  
         [0021]    [0021]FIG. 7 is a generalize cutaway view of a docking bay according to this invention, suitable for use in a host assembly like those illustrated in FIGS. 5 and 6 and configured to receive, electrically mate with, and retain an integrated computer module like the one shown in FIG. 1;  
         [0022]    [0022]FIG. 7A is a cutaway plan view of the integrated computer module partially inserted into a host assembly to illustrate engagement with the projecting member;  
         [0023]    [0023]FIG. 8 is an elevational view of an adapter PCB for transforming a standard 5¼″ peripheral bay of a conventional chassis into a docking bay according to this invention;  
         [0024]    [0024]FIG. 9 is a side view of the adapter PCB of FIG. 8 and an associated adapter sleeve that is externally sized for insertion into a standard 5¼″ drive bay and is internally sized for receiving an integrated computer module like the one shown in FIG. 1;  
         [0025]    [0025]FIG. 10 is a top view of the adapter sleeve of FIG. 9;  
         [0026]    [0026]FIG. 11 is a rear view of the adapter sleeve of FIG. 9; and  
         [0027]    [0027]FIG. 12 is a side view of a preferred bay configuration (shown here in connection with an adapter sleeve) wherein the host connector is incorporated into the edge of a main host PCB; 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
     A. The Integrated Computer Module  
       [0028]    [0028]FIG. 1 shows an integrated computer module (ICM)  100  that may be used in a host assembly having a docking bay according to this invention. From a structural point of view, the ICM  100  generally comprises a metal enclosure (not shown in FIG. 1, but see FIG. 2) that may be aesthetically surrounded by a case comprising, for example, a sleeve  180  and an associated bezel or faceplate  181 . The preferred faceplate  181  includes cooling apertures  186  and a handle  182  for carrying the ICM  100  and for pushing or pulling the ICM  100  into or out of a docking bay (not shown in FIG. 1). The preferred sleeve  180  includes at least one key feature such as chamfered edge  189  that mates with a corresponding key feature in the docking bay. In the example shown, key feature  189  comprises a chamfered edge along one corner of the substantially rectangular periphery of the sleeve  180  which mates with a corresponding chamfered corner  389  (shown in FIGS. 5,6) of the docking bay. The sleeve  180  and faceplate  181  are preferably injection molded components made of any suitable material such as ABS, PVC, or engineered plastics.  
         [0029]    The preferred ICM  100  of FIG. 1 also includes an aperture  184  in the faceplate  181  for exposing an optional PCI Mezzanine (PCM) card  160  that provides additional functionality such as an ethernet port, a SCSI port, or other desired function. A blank PCM cover plate (not shown) may be located in the aperture  184  in the absence of a PCM card  160 .  
         [0030]    [0030]FIG. 2 is an exploded view of the ICM  100  of FIG. 1, showing the presently preferred construction in more detail. The ICM  100  is designed so that it can be assembled by hand or more efficiently, and more cost effectively assembled using automated assembly techniques. In particular, the components of the preferred ICM  100  are generally assembled, from above, into an open-top case or “tub”  110 . The preferred ICM  100 , in other words, is assembled in a successively stacked, layer by layer arrangement. The tub  110  and all of the components therein are ultimately covered with a ceiling wall  119  and then, if appropriate for the desired application, enclosed in the sleeve  180  and faceplate  181  that form the outer case shown in FIG. 1. The preferred ceiling wall  119  makes a snap-on connection to the tub  110  to speed assembly and eliminate the necessity for any threaded fasteners or the like.  
         [0031]    The tub  110  has a floor wall  111 , a front wall  112 , back wall  113  opposite the front wall, a first side wall  114 , and a second side wall  115  opposite the first side wall. In order to define a space sized for receiving a disk drive  130 , an intermediate wall  116  is also provided between the first side wall  114  and the second side wall  115 . The tub  100  includes front and rear cooling apertures indicated at  107 ,  109  in the front and back walls respectively for passage of cooling air. The tub  110  is designed to minimize leakage of electromagnetic interference (EMI) in accordance with FCC requirements. Accordingly, the tub  110  and associated ceiling wall  119  are metallic and the cooling apertures  107 ,  109  are sized and configured to meet the desired EMI requirements at the frequencies of interest.  
         [0032]    The ICM&#39;s internal components generally include a shock mount system  120 , a disk drive  130  that is supported in the shock mount system  120  and may have a controller PCBA  131  mounted on one side thereof, an intermediate plate  140 , a main PCBA  150 , and an optional PCM expansion card  160  as mentioned above. Preferably, the main PCBA  150  includes a microprocessor such as an Intel Pentium (not shown) located beneath a suitable heat sink  153 , first and second memory module connectors  156  for holding memory modules  157  of a suitable type and desired capacity (e.g. Single Inline Memory Modules, or Dual Inline Memory Modules), and a module connector  154  for interfacing the overall ICM  100  to a host assembly. Collectively, the components mounted on the main PCBA  150  comprise substantially all the circuits needed for a computing subsystem. The ICM  100  further includes a locking mechanism  190  that engages a projecting member (discussed below) in the docking bay. The preferred locking mechanism  190  mechanically snaps into a corner of the tub  110  between an upper slot  118  and a lower slot (not shown).  
         [0033]    In a final assembly process, the tub  110  and its interior components are encased in the sleeve  180  and the associated faceplate  181 . As the faceplate  181  includes a handle  182  for carrying the entire ICM, it is important that the faceplate  181  have a secure, mechanical connection to the tub  110 . The presently preferred construction for such a positive, mechanical connection comprises two pairs of backwardly-extending fingers  187  having inwardly extending detents (not shown), one pair on each side of the faceplate  181 , and two corresponding pairs of slots  117  on the first and second side walls  114 ,  115  of the tub  110 . As suggested by FIG. 2, the faceplate  181  is initially pressed onto the tub  110  until the detents on its fingers  187  engage the slots  117 . Next, the tub  110  is inserted into the sleeve  180 , the sleeve  180  thereby encasing the tub  110  and the fingers  187  so that they cannot splay outward and disengage from the slots  117 .  
         [0034]    [0034]FIG. 3 shows a rear view of a fully assembled ICM  100 , the side that interfaces with a host assembly having a docking bay as described further below. As shown, substantially all of the back wall  113  is exposed at a rear end of the sleeve  180  to provide access to the module connector  154 , the cooling apertures  109 , and a module aperture  80 .  
         [0035]    [0035]FIG. 4 is a cross-sectional view of the preferred module aperture  80  in FIG. 3. In particular, FIG. 4 shows that the preferred module aperture  80  has radius edges  81  having a depth “D” that is greater than a width “W” of an annular groove  282  contained in a projecting member  280 . We make “D” greater than “W” to ensure that the module aperture  80  does not accidentally hang up on the projecting member  280  as described more fully below in connection with the locking mechanism and the host assembly. The preferred module aperture  80  is formed by stamping or punching through the back wall  113 .  
         [0036]    Referring once more to FIG. 2, the preferred shock mount system  120  comprises four corner pieces  126  and four buttons  146  that are each formed from an elastomeric material, the preferred material being Sorbathane sold by Sorbathane, Inc. The corner pieces  126  each have a base and two intersecting, substantially perpendicular walls (not separately numbered) extending upwardly from the base (not separately numbered). During assembly, the corner pieces  126  are simply located with their bases on the floor wall  111  of the tub  110 , and with their upstanding walls in the corners defined by the front wall  112 , the back wall  113 , the first side wall  114 , and the intermediate wall  116 . The upstanding walls of the corner pieces  126  are sized to provide a firm press fit relationship when compressed between the disk drive  130  and the surrounding walls  112 ,  113 ,  114 ,  116 . The four button  146  are placed in wells (not shown) formed in the intermediate plate  140  to capture an opposite side of the disk drive  130  as described further below.  
         [0037]    The presently preferred shock mounting system  120  requires us to orient the disk drive  130  with its controller board  131  facing upward, i.e. in a “board-up” orientation. The board-up orientation is preferred because it places the controller board  131  as close as possible to the main PCBA  150 , thereby allowing a short cable with minimal signal degradation. A short cable is not especially important in the context of an IDE connection to the disk drive. Because of ever increasing CPU power, however, the CPU may control the disk drive via an ordinary expansion bus such as the PCI bus. A short cable is critical in the context of a PCI connection to a disk drive. The board-up orientation is also preferred because the shock mounts  126  will not block access to the connectors  132  that are on the controller board  131 . It is also desirable to mount the disk drive  130  board-up because the other side of the disk drive presents a clean, solid volume for contact with the shock mount system  120 .  
         [0038]    The disk drive  130 , therefore, is oriented board side up and then pressed down onto and in between the four corner pieces. Next, the intermediate plate  140  is snapped into the tub  110 , between the first side wall  114  and an intermediate wall  116 , to firmly hold the disk drive  130  downward on the corner pieces  126 . Note that the controller board  131  is recessed into the disk drive&#39;s aluminum casting  132 , leaving a pair of elongated casting rails  133  extending up above the board  131 . The upper shock mounts (elastomeric buttons)  146  are bonded to the intermediate plate  140 . The buttons  146  press down against the elongated rails  133  of the casting  132 . Consequently, the buttons  146  isolate the intermediate plate  140  from the rails  133 , thereby enabling the shock mount system  120  to mechanically couple the disk drive  130  to the tub  110  via a shock-isolating, elastomeric interface.  
         [0039]    The intermediate plate  140  also protects the disk drive&#39;s controller board  131  from electromagnetic interference (EMI) emanating from the main PCBA  150 . The main PCBA  150  transmits significant amounts of RF energy over a wide frequency spectrum because it has synchronously clocked components that operate at relatively high power levels (e.g. greater than 5 watts) and at a plurality of relatively high clock frequencies (e.g. 66 MHz, 100 MHz, 500 MHz, and so on). The disk drive&#39;s controller PCBA  131 , on the other hand, contains circuitry that operates at relatively low millivolt levels that are associated with reading and writing data to and from the disk drive  130 . The intermediate plate  140 , therefore, beneficially functions as an EMI shield in addition to securing the disk drive  130  in the tub  110 . The preferred plate  140  is made of the same metallic material as the remainder of the tub  110  so that it represents an intermediate ground plane that tends to arrest conducted and radiated RF energy.  
         [0040]    [0040]FIG. 2A shows the intermediate plate  140  and its interconnection to the tub  110  in more detail. As shown therein, the intermediate plate  140  has a central section, a front edge, a back edge opposite the front edge, a first side edge, and a second side edge opposite the first side edge. The preferred intermediate plate  140  has a pair of tabs  141  on its first side edge which interface with a corresponding pair of slots (not numbered) in the first side wall  114 . The second side of the plate includes a pair of downwardly-extending fingers  143  that mate with one side of the intermediate wall  116  and an elongated lip  144  that mates with an opposite side of the intermediate wall  116 . The downwardly-extending fingers  143  have detents (see FIG. 2B) which mate with slots (not shown) in the intermediate wall  116 .  
         [0041]    [0041]FIG. 2B is an exploded view of FIG. 2A showing the preferred interconnection between the intermediate plate  140  and the disk drive  130  in the tub  110 . As shown, the intermediate plate  140  does not make direct contact with the disk drive  130 . Instead, four upper shock mounts  146  are bonded or otherwise attached to corresponding wells  145  in the intermediate plate  140 . The disk drive  130 , therefore, is encased and elastomerically supported between the tub  110  and the intermediate plate  140  by the lower shock mounts  126  (see FIG. 2) and the upper shock mounts  146 .  
         [0042]    As best shown in FIG. 2, the main PCBA  150  is secured in the tub  110  above the intermediate plate  140 . In the presently preferred embodiment, the main PCBA  150  is secured with two screws (not shown) that pass downward through two apertures—a central aperture  155  and a side aperture  159 . The central screw mates with a threaded aperture in the top of a standoff (not shown) that has a threaded fastener that extends from its bottom and is screwed into a threaded boss  147  (see FIG. 2B) in the center of the intermediate plate  140 . The side screw mates with a threaded aperture in the top of a similar standoff (also not shown) that screws into a threaded aperture located at one end of a shelf bracket (not shown) that is welded to the second side wall  115  of the tub  110 . The other end of the preferred shelf bracket has outwardly extending, vertically spaced fingers (not shown) that surround the top and bottom of the main PCBA  150  and thereby secure it at a third location. It is important, of course, to ground the main PCBA  150 . The preferred standoffs are conductive and make contact with corresponding traces that surround the main PCBA&#39;s central and side apertures to provide such grounding.  
         [0043]    The main PCBA  150  may be divided into two upper portions and two lower portions. The upper left half of the main PCBA  150  carries the CPU and its heat sink  153 . The upper right half carries a standard pair of PCM connectors  158  for interfacing the PCBA  150  with any PCM expansion card  160  that may be present. The majority left portion of the lower side of the main PCBA  150  rests closely against the intermediate plate  140  via support tabs  142  located to either side thereof and via a conductive standoff located near the plate&#39;s center (not shown). This portion of the PCBA&#39;s underside may carry some low-profile components, but it does not have any extending components due to its close proximity to the intermediate plate  140 . The minority right portion of the main PCBA&#39;s underside, however, carries a pair of memory sockets  156  that support a pair of memory modules  157  which extend downwardly therefrom next to the disk drive  130 , in-between the intermediate wall  116  and the second side wall  115 . An aperture (not shown) and associated cover plate  158  are provided on the tub&#39;s floor wall  111  and aligned with the memory modules  157  to provide access to the modules after the ICM  100  has been assembled.  
         [0044]    It is important to provide highly efficient cooling because of the high power dissipation and component density in the relatively low volume of the ICM  100 . Modern CPUs dissipate a significant amount of heat. For example, an Intel Pentium III processor operating at 500 MHz with a 512K L2 cache dissipates about 28 watts. The safe dissipation of this much heat requires a large, highly efficient heat sink  153 , the preferred heat sink being fabricated from aluminum because aluminum offers a good compromise between heat dissipation and cost. The main PCBA  150  is designed so that the CPU and its relatively large heat sink  153  extend upwardly from a topside of the PCBA  150  into an “air tunnel” (not numbered) located between the front and rear cooling apertures  107 ,  109  in the front and back walls. The ICM&#39;s built-in cooling fan  170  moves air through the air tunnel, over the fins of the heat sink  153 , with velocity of greater than 300 linear feet per minute (LFM). The cooling fan  170  is preferably located next to the front wall  112  of the tub  110 , next to the front cooling apertures  107 , in order to save some space, but the fan  170  could be located on the opposite side of the tub  110  if desired.  
       B. The Host Assembly—Generally  
       [0045]    [0045]FIGS. 5 and 6 show two host assemblies  200 A,  200 B. Both assemblies contain a power supply (not shown) for providing power to the host assembly and to the ICM  100  inserted therein. The first preferred host assembly  200 A of FIG. 5 contains a CRT display and is configured to appear like a conventional CRT monitor  201 A. The second preferred host assembly  200 B of FIG. 6 is configured to appear like a conventional full-height tower chassis  201 B that has a conventional disk drive bay  320  and may be connected to a display, a keyboard, and a mouse (not shown). Other configurations are possible. These two are merely illustrative examples.  
         [0046]    The preferred host assembly provides a docking bay that defines a cavity for receiving an ICM  100 . It is possible, however, to provide a docking module (not shown) that releasably connects an ICM  100  to other devices without providing a cavity  310  per se.  
         [0047]    The FIG. 5 host assembly  200 A uses a “built-in” docking bay  300  and associated cavity  310  having keying feature  389  for mating with module keying feature  189 . In operation, the user inserts the ICM  100  of FIG. 1 into the cavity  310  until the ICM&#39;s module connector  154  (see FIG. 3) mates with a host connector  254  (shown in FIG. 7) at the rear of the cavity  310 .  
         [0048]    The FIG. 6 host assembly  200 B, on the other hand, uses a “retrofit” docking bay adapter  400  that fits in a standard disk drive bay  320  and defines a cavity  410  having a host connector (not shown) and the keying feature  389  for receiving an ICM  100 . The cavity  410  in the retrofit adapter  400  also provides a host connector  254  (shown in FIG. 7) such that the user may insert the ICM  100  into the cavity  410 .  
       C. The Host Assembly—Bay Details  
       [0049]    [0049]FIG. 7 is a generalize cutaway view of a built-in docking bay  300  or retrofit adapter  400  according to this invention, the docking bay suitable for use in a host assembly  200 A,  200 B like those illustrated in FIGS. 5 and 6 and configured to receive, electrically mate with, and retain an ICM  100  like the one shown in FIG. 1.  
         [0050]    The docking bay has a cavity  310  defined by a continuous periphery, preferably rectangular, extending from a front opening (not separately numbered) to a back end  313  opposite the front opening. The cavity  310  may be regarded as having an insertion axis (arrow) that is perpendicular to the periphery. Two items of interest are located at the back end  313  of the cavity  310 : a host connector  254  for mating with the module connector  154  and a projecting member  280  for providing a data security function and an alignment function.  
         [0051]    The host connector  254  is located a particular XY (horizontal and vertical coordinate reference) connector location at the back end  313  of the cavity  310  so that it mates with the ICM&#39;s module connector  154  located at the same XY connector location when the ICM  100  is inserted into the cavity  310 . The host connector  254  may be centered on the back end  313  of the cavity, but the XY connector location is preferably asymmetric so that, in the absence of a key feature  189 , mating only occurs if the ICM  100  is in the “correct” orientation.  
         [0052]    The projecting member  280  extends into the cavity  310  in parallel with the insertion axis so that it may be received in a corresponding aperture  80  in the rear wall  113  of the ICM  100 . The projecting member  280  may be located at an asymmetric XY location at the back end  313  of the cavity to prevent the user from fully inserting an unkeyed ICM  100  into the cavity  310  in the wrong orientation. In either case, the preferred projecting member  280  is located at the lower right corner of the cavity&#39;s back end  313  so that the ICM  100  may conveniently receive it near the ICM&#39;s second side  115  (see FIG. 2). Other locations are possible.  
         [0053]    If the ICM  100  and docking bay  300 ,  400  are keyed, then the projecting member  280  will always mate with the aperture  80  in the rear wall  113  of the ICM  100 . In this preferred embodiment, the projecting member  280  provides a guiding function and a locking function, but it does not impact the ICM  100  because misalignment is not possible.  
         [0054]    In the case of an un-keyed ICM  100 , however, alignment is not assured. If the un-keyed ICM  100  is inserted in the correct orientation where the connectors  154 ,  254  are aligned for mating, then the projecting member  280  is simply received by the module aperture  80  in the rear wall  113  of the ICM&#39;s tub  110  (see FIG. 2). If the un-keyed ICM  100  is inserted upside down, however, then a solid portion of the rear wall  113  will contact the projecting member  280  before the ICM&#39;s rear wall  113  contacts and potentially damages the host connector  254  and before the cavity&#39;s rear end  313  contacts and potentially damages the module connector  154 .  
         [0055]    [0055]FIG. 7A shows the ICM  100  partially inserted into the docking bay  300 ,  400 . Note that the projecting member  280  extends beyond position “A,” i.e beyond the farthest most point of the host connector  254 . This length ensures that the projecting member  280  contacts the ICM&#39;s rear wall  113  before the host connector  254  contacts the rear wall  113  if the ICM is inserted upside down.  
         [0056]    The projecting member  280  also provides an alignment function that is best understood with reference to FIGS. 7 and 7A. As shown, the preferred projecting member  280  has an annular taper  284  at its tip that slidably mates with the radius edge  81  of the module aperture  80 . The radius edge  81  essentially defines an annular beveled recess that guides the module aperture  80  onto the projecting member  280 , and thereby further aligns the overall ICM  100  for mating the module connector  154  to the host connector  254 . The projecting member  280  must extend beyond position “A,” however, if it also to provide such an alignment function in cooperation with the module aperture  80 . As shown, in fact, the preferred projecting member  280  extends beyond reference position “A” to a farther reference position “B” to ensure that the module aperture  80  envelopes the projecting member  280  before the module connector  154  begins to mate with the host connector  254 . A benefit of this additional length is that ICM  100  contacts the projecting member  280  well before the position that the ICM  100  ordinarily sits when mounted in the bay. Accordingly, the user is given very obvious feedback, both tactile and visual, that the ICM  100  is not corrected situated.  
         [0057]    Suitably, the preferred connectors  154 ,  254  themselves include further complementary alignment features to ensure that a truly “blind” insertion is possible. A wide variety of cooperating connector styles may be used, including but not limited to, pin and socket types, card edge types, and spring contact types.  
         [0058]    Although not shown, the inventors contemplate an alternative embodiment of the ICM  100  that is secured to a host assembly in a semi-permanent arrangement. For cost reasons, the semi-permanent embodiment would omit the sleeve  180  and associated faceplate  181  and would replace the blind mating connector  154  with a more cost effective PCBA edge connector having conductive fingers made plated with minimal amounts of gold.  
         [0059]    [0059]FIGS. 7 and 7A also show that the projecting member  280  provides a data integrity feature in connection with the locking mechanism  190  contained inside of the ICM  100 . The projecting member  280 , in particular, includes a retention notch  282  located on the side thereof. The preferred retention notch  282  is provided in the form of an annular groove  282  that encircles the entire projecting member  280  and the preferred locking mechanism  190  includes a moveable pawl  194  that locks the ICM  100  into the docking bay  300 ,  400  by engaging the projecting member&#39;s annular groove  292 .  
         [0060]    The preferred projecting member  280  is made of a conductive material and is grounded so that it may serve as a means for managing ESD. It is generally desirable to discharge electrostatic energy through a resistance to reduce the magnitude of an associated current spike. Accordingly, the projecting member  280  itself may be comprised of a moderately conductive material such as carbon impregnated plastic or the projecting member  280  may be made of a highly conductive material such as metal and connected to ground through a discharge resistor as shown in FIG. 7A. In either case, the desired resistance is about 1-10 megohms.  
         [0061]    FIGS.  8 - 11  show a presently preferred construction for a “retrofit” docking bay adapter  400  as might be used in the standard drive bay  230  in the host assembly  200 B of FIG. 6. As shown, the retrofit adapter  400  comprises an adapter sleeve  420  and an adapter PCB  430  that is mounted to a back end of the adapter sleeve. The adapter sleeve  420  includes a suitable means for mounting to a standard drive bay  320  such as, for example, a plurality of threaded mounting holes  421  that are sized and spaced to interface with screws and corresponding through holes  321  (see FIG. 6) in a standard 5¼″ drive bay  320 . The preferred adapter sleeve  420  is formed of injection molded plastic. It includes a number of openings  425 , therefore, to reduce the required amount of plastic material.  
         [0062]    The adapter PCB  430 , shown from the rear in FIG. 8 and from the side in FIG. 9, carries the host connector  254 , the projecting member  280 , and suitable circuitry  434  for interfacing the adapter PCB  430  to other components in the host adapter.  
         [0063]    [0063]FIG. 12 is a side view of a preferred structure for supporting the host connector  254 . Here, instead of being supported on a separate PCB  430  as in FIGS. 8 and 9, the host connector  254  is incorporated into the edge of a main host PCB  250  in order to simply the construction and reduce costs. FIG. 12 shows such structure in connection with an adapter sleeve  400 , but is probably more applicable for use with a “custom” built-in docking bay  300  as used in a host assembly  200 A like that shown in FIG. 5, where more control can be exercised over the construction of the main host PCB  250  contained in the host assembly  200 A.