Abstract:
A system for facilitating airflow in a processor-based device, such as a server. The system is particularly amendable for use in low profile devices that inherently have reduced space for airflow. The system utilizes a tray deployed along a base wall or other wall of the device chassis. The tray is utilized to secure a cable or cables that would otherwise inhibit airflow.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to reducing airflow problems in low profile processor-based devices, such as servers, and particularly to a system for holding cables out of a cooling airflow passing through the device. 
     BACKGROUND OF THE INVENTION 
     Many current processor-based devices, such as servers, have been designed with a smaller overall package size. One dimension that has been reduced in a variety of devices is the height. For example, some servers have been designed with a low profile, such as 1 U servers, that have a relatively short distance between the bottom and the top of the server chassis. The lower profiles and otherwise smaller packages have created difficulty in providing an uninterrupted airflow through the device for cooling of components. 
     Exemplary components that tend to be obstructive to airflow include cables, such as SCSI cables, often used to form connections between one or more PCI cards and the motherboard. Placement of the cables can be difficult to control and they can end up in a position inhibiting airflow through the chassis of the device. 
     It would be advantageous to have a technique for reducing the airflow interference caused by such cables. 
     SUMMARY OF THE INVENTION 
     According to one embodiment of the present invention, a system is provided for reducing interruption to airflow through the chassis of a processor-based device, such as a server. The system includes a generally flat tray disposed along a base or floor of the chassis. The tray is designed to receive a cable, such as an SCSI cable. Typically, clips are used to secure the cable to the tray. 
     According to another aspect of the invention, a system is provided for facilitating better airflow through a server. The system includes a server chassis having a chassis floor. A cable retention tray is deployed along the chassis floor. The cable retention tray is designed to secure a generally flat cable along the chassis floor to reduce or prevent interference with airflow through the chassis. 
     According to another aspect of the present invention, a method is provided for facilitating cooling of components in a processor-based device, such as a server. The method includes deploying a generally flat tray along an area of the chassis that reduces interference with airflow. The method further includes laying a low profile, signal carrying cable along the tray where it is retained at a position substantially out of the path of airflow. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and: 
     FIG. 1 is a perspective view of a rack with a plurality of processor-based devices, e.g. servers, mounted therein; 
     FIG. 2 is a front view of a low profile server; 
     FIG. 3 is a partially exploded perspective view of the server illustrated in FIG. 2; 
     FIG. 4 is a cross-sectional view taken generally along line  4 — 4  of FIG. 3; 
     FIG. 5 is a perspective view of a cable tray disposed within the chassis of an exemplary server; 
     FIG. 6 is a cross-sectional view taken generally along line  6 — 6  of FIG. 5; 
     FIG. 7 is a perspective view of a PCI card riser assembly designed for mounting in a low profile chassis of an exemplary server; 
     FIG. 8 is a cross-sectional view of the PCI card assembly taken generally along line  8 — 8  of FIG. 7; 
     FIG. 9 is a cross-sectional view similar to FIG. 8 but showing the PCI card assembly in an eject position; 
     FIG. 10 is a perspective view of the right end of the riser assembly illustrated in FIG. 7; 
     FIG. 10A is a perspective bottom view of the riser assembly illustrated in FIG. 7; 
     FIG. 11 is a partial front view of an exemplary server illustrating an indicator; 
     FIG. 12 is partial rear view of an exemplary server illustrating a rear indicator; 
     FIG. 13 is a circuit diagram for use with the indicators illustrated in FIGS. 11 and 12; 
     FIG. 13 a  is a diagram representing the functionality of the circuit illustrated in FIG. 13; 
     FIG. 14 is a perspective view of a retractable LCD module in a retracted position within an exemplary server; 
     FIG. 15 is a perspective view of the retractable LCD unit illustrated in FIG. 14 but in an open or operable position; 
     FIG. 16 is a top view of the LCD unit in an open position; 
     FIG. 17 is a top view similar to FIG. 16 but with the LCD unit in a retracted position; 
     FIG. 18 is a top view of a cable management system deployed with an exemplary server that is retracted in a rack; 
     FIG. 19 is a top view of the cable management system illustrated in FIG. 18 with the exemplary server extended from the rack; 
     FIG. 20 is a perspective view of a portion of an exemplary rack and rail; and 
     FIG. 21 is an exploded view of an end of the rail illustrated in FIG.  20 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring generally to FIG. 1, an exemplary implementation of the present invention is illustrated. In this embodiment, a plurality of densely packaged, processor-based devices  30  are shown mounted in a rack system  32 . Rack system  32  is designed to slidably receive a plurality of the processor-based devices  30 . Typically, devices  30  are mounted on retractable rails that permit the device to be moved between a retracted position within rack  32  and an extended position in which the device is at least partially extended from rack system  32 . This extension allows removal or servicing of an individual device  30 , as illustrated in FIG.  1 . 
     Throughout this description, an exemplary processor-based device is described and referenced as server  30 , but other devices also can benefit from the unique features described herein. The exemplary server  30  is a low profile server, such as a 1 U server designed to occupy one unit of vertical space in rack system  32 . 
     Server  30  includes a chassis  34  having a front  35  designed with pair of drive bays  36 . Drive bays  36  are configured to receive a pair of hot pluggable drives  38 . The front of chassis  34  also may be designed to receive an ejectable CD drive assembly  40  and an ejectable floppy drive assembly  42 . In the particular design illustrated, CD drive assembly  40  and floppy drive assembly  42  are combined and removable or insertable as a single unit. The exemplary design also includes other features, such as a retractable liquid crystal display (LCD)  44  and an indicator panel  46 . 
     In server  30 , components are densely packaged, but adequate cooling of the components is maintained. As illustrated in FIG. 3, chassis  34  is divided into at least two general zones, including a high pressure, high airflow zone  48  and a relatively low pressure, low flow zone  50 . An airflow is created into high pressure zone  48  by a blower assembly  52 . Blower assembly  52  typically includes a fan  54 , such as a centrifugal fan, e.g. an exemplary blower unit is a  24  volt Gamma blower. Similarly, airflow through low pressure zone  50  is created by a blower  56 . In the embodiment illustrated, blower  56  comprises a fan integral with an internal power supply  58  oriented such that its fan discharges airflow into low pressure zone  50 . 
     Preferably, blower assembly  52  discharges airflow at a greater rate and pressure than blower  56 . Thus, the air pressure created in high pressure zone  48  is maintained at a higher level than the air pressure in low pressure zone  50  during operation of the fans. This ensures sufficient airflow across densely packed, heat producing components disposed within high pressure zone  48  of chassis  34 . 
     To ensure that minimal high pressure air from zone  48  flows into low pressure zone  50 , open areas between the zones have been blocked by an air baffle  60 . Air baffle  60  prevents the output of blower assembly  52  from disrupting the air flow created through low pressure zone  50  by blower  56 . 
     Exemplary components disposed in high pressure zone  48  include one or more, e.g. two, processors  62 , each coupled to a corresponding heat sink  64 . Each heat sink  64  includes a plurality of cooling fins  66  that decrease in height along an inwardly directed end to provide additional room for other components. For example, a plurality of memory modules  68 , e.g. DIMMs, may be mounted within high pressure zone  48  at an angle to facilitate the low profile design of chassis  34 . In this embodiment, memory modules  68  are disposed at an angle over at least one of the heat sinks  64 , but the decreasing height of the inwardly disposed cooling fins permit the memory modules to be so oriented without contacting the heat sink. Another exemplary component disposed in high pressure zone  48  is a PCI card  70 . 
     In operation, blower assembly  52  draws air in along drives  38  and discharges the airflow into high pressure zone  48 . The size and capacity of the fan is adjusted according to the size of chassis  34  and the layout of components disposed in high pressure zone  48 . However, the capacity should be sufficient to create enough pressure in high pressure zone  48  that the necessary quantity of cooling air passes across the components disposed in zone  48 , e.g. heat sinks  64  and memory modules  68 . 
     Preferably, the airflow is discharged towards the rear of chassis  34 . In the illustrated embodiment, chassis  34  includes a cutout region  72  for receiving an air outlet or vent through which air is discharged from high pressure zone  48 . For example, a vent region  74  may be disposed in a cover  76  designed to fit over chassis  34  and enclose high pressure zone  48  and low pressure zone  50 . Vent region  74  is disposed in a “scooped” region  78  of cover  76 . When cover  76  is disposed on chassis  34 , scooped region  78  extends inwardly into the interior of chassis  34  in high pressure zone  48  along cutout region  72 . As illustrated best in FIG. 5, vent region  74  includes a vent and preferably a plurality of vents  80  that permit the airflow to exit generally in a direction in line with the discharge from blower assembly  52 . Exemplary vents  80  are formed as a plurality of louvers along scooped region  78 . 
     Cover  76  also may include an air inlet  82  and an air outlet  84  for blower  56 , or alternatively, inlet  82  and outlet  84  can be formed through chassis  34 . As blower  56  is operated, air is drawn through inlet  82  along the combined CD/floppy drive and into the power supply assembly  58 . The air is discharged from blower  56  into low pressure zone  50  until it exits through outlet  84 . Low pressure zone  50  may include a variety of components that vary according to the design of chassis  34  and server  30 . In the exemplary embodiment, low pressure zone  50  includes a PCI card  86 , an inline EMI filter  88  and an internal array controller cable tray  90 . 
     Other features of server  30  include a dual PCI card and an ejectable riser assembly  92  to which PCI cards  70  and  86  are attached. Also, DIMM modules  68  and processors  62  preferably are attached to a motherboard  94 . Drives  38  are coupled to a removable SCSI back plane  96 . A raid on a chip (ROC) board  98  is disposed intermediate blower assembly  52  and power supply  58 . A power switch and LED PC board  100  is deployed within chassis  34  generally proximate indicator panel  46  for cooperation therewith. A back plane  102  for the combined CD and floppy assembly is deployed between floppy drive assembly  42 /CD assembly  40  and power supply  58 . Additionally, a pair of mounting rails  104  can be attached to the sides of chassis  34  to permit engagement with corresponding rails of rack system  32 , as described below. It should be noted that a variety of component arrangements can be utilized, however, the exemplary illustrated arrangement provides for a dense packaging of components separated into two cooling zones that are able to readily maintain the components at desirable operating temperatures. Several of the unique, inventive features that facilitate the above-described packaging are described below. 
     One of the unique features of server  30  is cable tray  90 . In low profile servers, such as the illustrated 1 U server, larger SCSI cables can interfere with the fit of internal components as well as being detrimental to thermal performance, e.g. heat removal. Cable tray  90  is designed to hold an SCSI cable  106  and to lie generally flat along a floor  108  of chassis  34 . The low profile tray holds cable  106  substantially out of the airflow through low pressure zone  50 . Thus, cable  106  can be used to form an electrical connection between a PCI card and motherboard  94  without interrupting airflow and thermal performance. Preferably, cable tray  90  includes a flat base  109  and a plurality of tabs  110  that extend over and retain cable  106 , as illustrated in FIGS. 5 and 6. Preferably, tabs  110  extend upwardly from flat base  109  and may be integrally formed with flat base  109 , as by plastic injection molding. 
     In the particular embodiment illustrated, SCSI cable  106  is connected to the board edge of motherboard  94  by an SCSI connector  112 . Electrically, a control signal is implemented on an internal SCSI connector for an adapter to electrically switch the signal paths from being driven by an onboard controller to being driven by the adapter controller. The signal path preferably is optimized so that when no adapters are plugged in, there will be negligible impact on the signal quality. 
     Another feature that facilitates the dense packaging of components within chassis  34  is riser assembly  92 , illustrated best in FIGS. 7 through 10A. The design of riser assembly  92  permits the mounting of at least two full length PCI cards, such as PCI cards  70  and  86 , as illustrated in FIGS. 8 through 10. Riser assembly  92  includes a framework  120  having a center frame portion  122  disposed between PCI cards  70  and  86  and a pair of frame ends  124 ,  126  that are disposed generally perpendicular to center frame portion  122 . Frame ends  124  and  126  preferably are spaced apart to slidably receive PCI cards  70  and  86 . Typically, each frame end  124  and  126  includes appropriate supports  128  for supporting each PCI card. 
     Additionally, riser assembly  92  includes a PCI riser card  130  disposed along center frame portion  122 . A pair of oppositely facing connectors  132  are electrically coupled to PCI riser card  130  and extend in opposite directions therefrom for coupling with PCI card  70  and PCI card  86 . Connectors  132  are mounted to PCI riser card  130  in a vertically staggered arrangement. Additionally, a riser card connector  134  is mounted to riser card  130  and configured for connection with motherboard  94  at a connection location  136  (see FIG. 6) to permit communication with PCI cards  70  and  86 . 
     Additionally, riser assembly  92  includes a lever and preferably a pair of levers  138  connected by a handle  140 . Lever or levers  138  are pivotably mounted to riser assembly  92 , preferably at center frame portion  122  for pivotable motion about a pivot mount  142 . Each lever  138  also includes an engagement end  144  that has an engagement feature, such as a recess  146  designed to engage a rib  148 , typically mounted on chassis floor  108  (see also FIG.  6 ). 
     When riser assembly  92  is moved downwardly into chassis  34  (generally over cable tray  90 ), engagement end  144  and recess  146  engage rib  148 , as illustrated best in FIG.  9 . Handle  140  is then pressed to pivot lever  138  about pivot  142 , thereby driving riser card connector  134  into engagement with a corresponding connector, e.g. a connector on motherboard  94 , and riser assembly  92  into proper position. To remove riser assembly  92 , handle  140  simply is pulled upwardly which moves riser assembly  92  and riser card connector  134  laterally to permit lifting of the entire assembly from chassis  34 . 
     It should be noted that riser assembly  92  may be further secured in chassis  34  by a plurality of engagement features. For example, as illustrated in FIGS. 10 and 10A, a plurality of pins and receptor slots can be used to secure riser assembly  92  into chassis  34  when levers  138  are pivoted to an installed position. As illustrated in FIG. 10, frame end  126  may be designed with a pin  150  and a receiving slot  154  that are located for engagement with a corresponding receiving slot  152  and pin  156 , respectively, that are attached to chassis  34  (see FIGS.  4  and  5 ). In this embodiment, receiving slot  154  is formed in a tab  158  that extends upwardly from chassis floor  108  (see FIGS.  5  and  6 ), and pin  156  also is formed to extend generally upwardly from chassis floor  108  for sliding engagement with receiving slot  152 . 
     As illustrated best in FIGS. 10 and 10A, riser assembly  92  may also include one or more, e.g. two, pegs  160  that extend generally downwardly from the bottom of center frame portion  122 . Pegs  160  are located for engagement with corresponding slots  162  formed in a bracket  164  mounted to chassis floor  108  (see also FIG.  6 ). Bracket  164  and slots  162  are designed to engage and retain pegs  160  when levers  138  move riser assembly  92  into its installed position, as illustrated best in FIG.  8 . 
     Another unique feature of server  30  is an indicator system  162  illustrated in FIGS. 11 through 13. Indicator system  162  permits a technician to identify the appropriate server  30 , or other processor-based device, that requires attention and to disconnect the unit without risking disconnection of the wrong unit. 
     When multiple servers are mounted in a rack, particularly when the units have low profiles, such as 1 U servers, it can be difficult for a technician to ensure that he or she unplugs the proper unit at the rear when the unit was initially identified from the front. Thus, indicator system  162  can be activated to provide an indicator of the desired server from the front of the server and from the rear of the server. A variety of tags, logos, audible indicators etc. could be activated by an actuator to provide appropriate designation of the server requiring attention. 
     However, a preferred indicator system  162  provides a front switch  164  and a front light  166 , as illustrated in FIG.  11 . Similarly, exemplary indicator system  162  provides a rear switch  168  and a rear light  170 , as illustrated in FIG.  12 . When either front switch  164  or rear switch  168  is depressed while lights  166  and  170  are off, both lights  166  and  170  are illuminated. If either switch  164  or  168  is depressed while lights  166  and  170  are illuminated, both lights  166  and  170  turn off. 
     This allows an individual to identify a unit requiring attention from the front. Once identified, front switch  164  is depressed to illuminate front light  166  and rear light  170 . The individual may then walk around to the back of a rack containing multiple units, identify the unit having an illuminated rear light  170 , and unplug cables from the unit. The unit then can be removed from the front of the rack for service or replacement. This prevents the inadvertent disconnection of the wrong unit. Lights  166  and  170  preferably have a visually noticeable color, such as a blue color. 
     An exemplary circuit for use in indicator system  162  is illustrated in FIG.  13  and the functionality of the circuit is illustrated in FIG. 13 a . The exemplary circuit may be powered by an auxiliary power supply Vaux  172 . Power supply  172  may be separated from the main system power supply which allows the circuitry to be operated even when the main system power is off. Other components of the circuit include a NAND-gate  174 , a D-flipflop  176  and an inverter  178 . 
     In this exemplary embodiment, the D-flipflop  176  is illustrated after its reset condition, that is its output Q is low and Q/ is high. When either push button  164  or  168  is depressed, the signal line PUSH/ (labeled  172   a ) level changes from high to low. This signal transition causes the clock input signal, CLK  166   d , of D-flipflop  176  to change from low to high, via NAND-gate  174 . The clock signal latches the high state at the D input, therefore changing the Q output (labeled  166   c ) from low to high. Because the Q output signal is passed through the inverter  178 , the signal (LED-ON/  166   a ) at the cathode pins of LEDs  166  and  170  is changed from high to low. This turns on or illuminates LEDs  166  and  170 . At this time, the D input of the flipflop  176  is low. When either push button  164  and or  168  is depressed again, the CLK input latches the low state from the D input, causing the Q output, STATUS  166   c , to change from high to low. This transition goes through the inverter  178 , effectively turning off both LED  166  and LED  170 . 
     In the embodiment illustrated, one of the NAND-gate  174  inputs also can be controlled by software designed to allow LEDs  166  and  170  to be turned on, turned off or blinked. Application software on the server or on a remote server can be utilized to control the state of the LEDs. The D-flipflop  176  output Q/, STATUS/ 166   b , also can be monitored by software. This would allow a technician from a remote site to control the state of LEDs  166  and  170  and to notify another technician in the server room as to which server requires service. Upon completion of the service work, the servicing technician would then push either button  164  or  168 . The remote technician is thereby able to monitor the LED status and to determine completion of the service work. It should be noted that the figure and functionality described are exemplary, and other circuits can be used to accomplish the device identification described above. 
     Another unique feature of the exemplary server  30  is the retractable LCD  44 , illustrated in FIGS. 14 through 17. The liquid crystal display module  44  can be moved between a retracted position, as illustrated in FIG. 14, and a display or open position, as illustrated in FIG.  15 . The LCD module includes a display  180  that can be used as a visual interface for various information related to the operation of server  30 . However, when LCD module  44  is not in use, it can be moved to the retracted position to permit access to CD drive assembly  40  and floppy drive assembly  42 . 
     LCD module  44  is pivotably mounted to a retraction assembly  182  by a module pivot  184  that allows LCD module  44  to be pivoted between the display position and a position generally perpendicular to the front of server  30  for retraction. Retraction assembly  182  includes an outer guide housing  186  disposed generally between floppy drive assembly  42 /CD drive assembly  40  and drive bays  36 . Outer guide housing  186  is designed to slidably receive LCD module  44  therein. 
     Retraction assembly  182  further includes a pivot mount bracket  188  to which module  44  is pivotably mounted via pivot  184 , as best illustrated in FIGS. 16 and 17. Generally opposite pivot  184 , bracket  188  includes one or more attachment features  190  to which one or more resilient members, such as a pair of springs  192  can be attached. Preferably, a pair of springs positioned above and below each other are used to balance the biasing force on pivot mount bracket  188  and LCD module  44  as LCD module  44  is drawn into an open interior  194  of outer guide housing  186 . Exemplary springs  192  include coil springs that are pulled to a stretched position when LCD module is moved to its open or display position. Thus, the coil springs bias LCD module  44  back into open interior  194  when module  44  is pivoted to a position generally in alignment with open interior  194 . An appropriate electric line or lines  195  may be routed to LCD module  44  through outer guide housing  186 , as best illustrated in FIGS. 16 and 17. 
     When units, such as servers, are stacked sequentially in rack system  32 , the various cables coupled to the various server ports can be difficult to manage. This is particularly true with low profile servers, such as 1 U servers, due to the relatively large number of closely spaced units. Accordingly, the densely stacked servers benefit from a cable management system  200 , such as that illustrated in FIGS. 18 and 19. The exemplary cable management system  200  includes a tray bracket  202  mounted to and extending rearwardly from each server  30 . At least one and preferably a pair of spools  204  serve as a cable support member and are mounted to tray bracket  202  in a position that permits the plurality of various cables  206  to be wrapped and held generally along the backside of server  30 . Spools  204  can be mounted in a variety of locations depending on the design of server  30  and rack system  32 , but the spools are preferably located in positions to provide strain relief for the cables and to bundle the cables for routing. 
     Cable management system  200  further includes a tension device  208  and a retainer member  210 . Tension device  208  and retainer  210  preferably are mounted towards the back of rack system  32  generally on a level with server  30 . Retainer  210  may be mounted or formed at a position on an opposite side of rack system  32  from tension device  208 , as illustrated in FIGS. 18 and 19. Retainer  210  also is positioned slightly rearward of tension device  208 . 
     In an exemplary embodiment, tension device  208  comprises a tension reel  212 , such as a torsion spring loaded reel, having an extensible member  214 , such as a cord or cable. Extensible member  214  is connected to cable bundle  206  at a location intermediate the cable connectors plugged into the rear of server  30  and retainer  210 . Specifically, extensible member  214  is connected to cable bundle  206  generally intermediate the position at which cable bundle  206  is in contact with retainer  210  and the position of the closest spool  204 . Thus, when a specific server  30  is slid to an extended position in rack system  32 , extension member  214  is pulled outwardly, as illustrated in FIG.  19 . However, when the server is returned to its retracted position within rack system  32 , extension member  214  is retracted into tension reel  212 , thereby pulling cable bundle  206  to a neatly folded position to the rear of server  30 , as illustrated in FIG.  18 . 
     When multiple thin profile devices, e.g. servers, are mounted in a rack system  32 , a rack rail must be positioned for engagement with the side mounting rails  104  attached to chassis  34  of each device  30 . With low profile devices, multiple rails must be deployed in rack system  32  to receive the multiple corresponding servers. To facilitate assembly of rack system  32 , and specifically the attachment of rack rails for supporting each device  30 , unique rails have been designed for easy insertion and removal. 
     As illustrated best in FIG. 20, a preferred rack system includes a front support member  220  and a back support member  222  on each side of rack system  32 . Front support member  220  includes a plurality of mounting openings  224  that inhabit a substantial portion of the member. Similarly, rear support member  222  includes a plurality of mounting openings  226  that extend upwardly for a substantial distance along the support member. The mounting openings are designed to receive a rail  228  that extends from the front to the rear of rack system  32  between front support member  220  and rear support member  222 . It should be noted that mounting openings  224  and  226  can be in a variety of configurations and can be changed to mounting tabs, brackets or other features able to engage the corresponding mounting ends of each rail  228 . 
     In the illustrated embodiment, each rail  228  includes a rear mounting end  230  and a front mounting  232 . Each mounting end  230 ,  232  includes engagement features for engaging the mounting structures along front and rear support members  220 ,  222 . In the exemplary, illustrated embodiment, rear mounting end  230  and front mounting end  232  each include a pair of tabs  234  sized and spaced for receipt in corresponding mounting openings  222 . Thus, rail  228  may be positioned at multiple different locations along support members  220  and  222 . 
     In the preferred embodiment, rear mounting end  230  is fixed and front mounting end  232  is resiliently movable. Alternatively, rear mounting end  230  can be made resiliently movable, or both mounting ends can be made resiliently movable. Regardless, an exemplary resiliently movable mechanism  236  is illustrated best in FIG.  21 . 
     In this embodiment, rail  228  includes a first rail portion  238  and a second rail portion  240  that may be slidably coupled to first rail portion  238  by a plurality of pins or fasteners  242 . As illustrated, second rail portion  240  is formed with a pair of slots through which pins  242  extend into contact with corresponding mounting brackets  244  disposed on the interior of first rail portion  238 . Heads  246  of pins  242  retain second rail portion  240  slidably trapped against first rail portion  238 . In this embodiment, front mounting end  232  is formed at the front of second rail portion  240  for selective, sliding movement into and out of engagement with mounting openings  224  of front support member  220 . Front mounting end  232  may include a bumper  248  to buffer the contact between first rail portion  238  and second rail portion  240  when sliding second rail portion  240  farther into first rail portion  238 . 
     To ensure that rear mounting end  230  and front mounting end  232  remain firmly connected to rear support member  222  and front support member  220 , respectively, second rail portion  240  is biased outwardly from first rail portion  238  by a biasing system  250 . An exemplary biasing system  250  includes a coil spring  252  disposed within a channel  254  located on the interior of first rail portion  238 . An abutment tab  256  is disposed at an interior end of channel  254 . A second abutment tab  258  extends inwardly from second rail portion  240  generally at an end of spring  252  longitudinally opposite of abutment tab  256  when second rail portion  240  is slidably mounted to first rail portion  238 . 
     Thus, spring  252  biases second rail portion  240  and mounting end  232  in an outward direction to firmly move rear mounting end  230  and front mounting end  232  into engagement with rear support member  222  and front support member  220 , respectively. However, rail  228  can quickly and easily be removed by overcoming the bias of spring  252  and forcing second rail portion  240  to slide inwardly into first rail portion  238 . This resilient, movable mechanism  236  permits quick installation and removal of rails  228  from rack system  32  to accommodate the mounting of multiple devices, such as servers without the use of screws or other types of fasteners. 
     The actual features of rails  228  by which each server  30  is slidably mounted thereto depends on the configuration of mounting rails  104 . However, a variety of available sliding rails  104  and corresponding mounting rails  228  can be utilized, as known to those of ordinary skill in the art. 
     It will be understood that the foregoing description is of preferred embodiments of this invention, and that the invention is not limited to the specific forms shown. For example, a variety of devices other than servers can benefit from the various features described herein; the configuration of the overall chassis and the location of components can be adjusted according to a specific application; the size and capacity of the blower assemblies can be adjusted according to each application; and a variety of materials can be utilized in the construction of various components described herein. These and other modifications may be made in the design and arrangement of the elements without departing from the scope of the invention as expressed in the appended claims.