Abstract:
A rack mounted computer system. In one variation the computer rack is configured for side-by-side placement of computers. In another variation, the computer rack includes flanges for supporting the placement of computer units within the rack. In another variation the computer rack is configured with retaining clips. In yet another variation, the computer rack is configured to receive computers with chassis that are adapted for side-by-side placement.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a divisional application of U.S. application Ser. No. 12/407,744 filed Mar. 19, 2009 entitled “RACK MOUNTED COMPUTER SYSTEM,” which is a divisional application of U.S. application Ser. No. 11/125,942, filed May 9, 2005, entitled “RACK MOUNTED COMPUTER SYSTEM,” now U.S. Pat. No. 7,529,097 issued May 5, 2009, which claims the benefit of U.S. provisional patent application No. 60/569,025, entitled “RACK MOUNTED COMPUTER SYSTEM” filed on May 7, 2004, U.S. provisional patent application No. 60/568,969 entitled “INTERFACE ASSEMBLY”, filed May 7, 2004, U.S. provisional patent application No. 60/569,020 entitled “ELECTROMAGNETIC INTERFERENCE SHIELD FOR I/O PORTS”, filed May 7, 2004, and U.S. provisional patent application No. 60/569,019 entitled “DIRECTIONAL FAN ASSEMBLY”, filed May 7, 2004, each of which is incorporated herein by reference in it entirety. 
     
    
     BACKGROUND 
       [0002]    As information technology has rapidly progressed, computer network centers such as server farms and server clusters have become increasingly important to our society. The server farms provide efficient data processing, storage, and distribution capability that supports a worldwide information infrastructure, which has come to dominate how we live and how we conduct our day to day business. 
         [0003]    Typically, at a site where numerous computers are connected to a network, the computers and related equipment are stacked in racks, which are arranged in repeating rows. In conventional systems, the racks are configured to contain computer equipment having a standard size in compliance with the Electronic Industries Alliance (“EIA”) “rack unit” or “U” standard. Each computer would have a height of 1 U, 2 U, or some U-multiple, with each U corresponding to approximately 1.75″. 
         [0004]      FIG. 1  shows a conventional rack  100  measuring roughly 19 inches wide, 30 inches deep and 74 inches high. This rack  100  is formed of a rectangular frame structure having four vertical supports  102  (two in the front and two in the back), each support  102  having a plurality of holes  104  (typically rectangular) formed along its length. Horizontal rails, which are used to support each individual component to be mounted in the rack, are attached to the vertical supports  102  using cage nuts that are passed through the holes in the supports. Walls may be attached to the sides and top of the frame structure and doors may be provided on the front side  105   a  and back side  105   b  in order to provide a complete enclosure for the rack system. 
         [0005]    Each computer mounted in the rack  100  may comprise a computer chassis supporting a main board. The main board may be alternatively referred to as the motherboard or system board. The main board comprises the primary printed circuit board (PCB) of a computer. The basic circuitry and components used by a computer to function are generally either contained in or attached to the main board. The main board typically contains the system bus, processor and coprocessor sockets, memory sockets, serial and parallel ports, expansion slots, and peripheral controllers. 
         [0006]    By providing the vertical supports with a plurality of holes, a great deal of flexibility in the placement of the horizontal rails can be achieved. Accordingly, a wide variety of heights of components can be accommodated by the rack frame structure. However, the manual positioning and installation of each rail can be a time-consuming and labor-intensive process, significantly increasing the total cost of the system. 
         [0007]    A recent trend in rack-based computer systems has been towards increasing the density of computers that will fit into each rack. This increase in density has been achieved by decreasing the height of each computer, while maintaining the width and depth dimensions of the computer so that the computer can still be mounted into a conventional computer rack. Thus, each computer chassis is made very wide, very deep, and very short, often just 1 U in height. The motherboard that is contained in each computer is typically a relatively flat printed circuit board which can be easily placed into such a wide, deep, and flat computer chassis. However, layout difficulties arise when trying to add the additional components which are either mounted onto or attached to the motherboard to form a functional computer. These components include, for example, hard drives, removable media drives, power supplies, microprocessors, microprocessor heat sinks, fans, and memory. Because of the low profile of the computer chassis, there is very little room above the motherboard for positioning these components. Generally, the motherboard has a footprint (i.e., width and depth of the motherboard) that is significantly smaller than the footprint of the computer chassis. Thus, these other components are typically positioned in the space available in the chassis adjacent to the motherboard. However, the short height of the chassis limits the number and size of components that can be placed here. 
         [0008]    The dense packing of components in these low-profile computer chassis presents cooling problems as well. Rack-based computer systems are typically cooled by directing air through each computer chassis in a front-to-back direction. Because the 1 U computer chassis are so thin, any component contained within the computer chassis can significantly impede the flow of air through the computer chassis and across all of the components. This can produce “hot spots”, which are regions that do not receive sufficient airflow, thereby enabling heat to accumulate. 
         [0009]    This airflow problem can be particularly problematic when attempting to cool the main processor or processors in the computer. Many processors (sometimes referred to as a “central processing unit” or “CPU”) generate tremendous amounts of heat during operation and are provided with heat sinks to dissipate this generated heat. These heat sinks may be passive heat sinks, which cool the processor by conducting the heat away from the processor using fins. The heat can then be drawn away from the fins and out of the chassis by the cooling airflow. Alternatively, the heat sinks may be active heat sinks, which actively draw heat away from the processor, using, for example, dedicated processor fans. In either case, the heat sink increases the overall thickness of the processor assembly. In some cases, when the processor and heat sink are mounted onto a motherboard, the overall assembly is over 1.75″ thick, preventing its use in 1 U chassis systems. Even when the processor and heat sink are sufficiently thin that they can fit into the chassis, there is very little additional clearance around the heat sink, thereby preventing cooling air from effectively cooling the processor. Furthermore, the dense packing of additional components can also impede the flow of air across the processor and heat sink. Accordingly, the progression towards increasing thin rack-based computers has produced both packaging and cooling problems for some computer systems. 
         [0010]    Another problem which faces operators of rack mounted computer systems is the difficulty of servicing the computers for repairs or upgrades. Conventional rack mounted computer components may be provided with flanges that extend from the sides of the front face of the computer chassis. Each of these flanges may be configured with two mounting holes which can be aligned with the holes  102  provided on the vertical supports  102  of the rack  100 . A pair of screws or bolts may be passed through these aligned holes in each flange in order to secure the computer to the rack  100 . Thus, each time the computer chassis is mounted in the rack, these screws need to be attached, and each time the computer chassis is removed, these screws must be detached. 
       BRIEF SUMMARY 
       [0011]    In accordance with embodiments of the present invention, a computer system is provided, comprising: a rack assembly; a first computer system comprising a first computer chassis and a first main board contained in the first computer chassis, the first computer system being supported in the rack assembly such that the first main board is in a substantially horizontal orientation; and a second computer system comprising a second computer chassis and a second main board contained in the second computer chassis, the second computer system being supported in the rack assembly such that the second main board is in a substantially horizontal orientation and the second computer system is laterally adjacent the first computer system. 
         [0012]    In accordance with embodiments of the present invention, a method of assembling a computer rack is provided, comprising: forming a first support plate by cutting a first plurality of support flanges in a first plate, the first plate defining a first plane, and bending each of the first plurality of support flanges such that each support flange defines a support surface substantially perpendicular to the first plane; forming a second support plate by cutting a second plurality of support flanges in a second plate, the second plate defining a second plane, and bending each of the second plurality of support flanges such that each support flange defines a support surface substantially perpendicular to the second plane; and positioning the first and second support plates in a computer rack frame such that a plurality of computer chassis can be supported between the first and second support plates by the first and second pluralities of support flanges. 
         [0013]    In accordance with embodiments of the present invention, a computer system is provided, comprising: a rack frame; a first plate comprising a first plate body and a first plurality of support rails integrally formed with the first plate body; a second plate opposite the first plate and comprising a second plate body and a second plurality of support rails integrally formed with the second plate body, said first and second pluralities of support rails being positioned to support a plurality of computer chassis. 
         [0014]    In accordance with embodiments of the present invention, a rack-mount computer system is provided, comprising: a rack assembly, comprising a plurality of computer bays, each computer bay comprising at least one computer retaining recess provided along an interior portion of the computer bay; and a computer chassis configured to be received in one of the computer bays, the computer chassis comprising a chassis retainer configured to mate with the computer retaining recess when the computer chassis is fully inserted into the computer bay. 
         [0015]    In accordance with embodiments of the present invention, a rack-mount computer is provided, comprising: a main board comprising a printed circuit board, at least one processor, and memory; and a computer chassis containing the main board, the computer chassis comprising: a front side having at least one aperture to allow cooling air to pass therethrough, and a back side having at least one aperture to allow cooling air to pass therethrough; wherein the computer chassis has an interior width less than 1″ greater than a width of the printed circuit board. 
         [0016]    In accordance with embodiments of the present invention, a rack-mount cluster module is provided, comprising: a cluster module chassis comprising a plurality of bays, each bay configured to receive a computer; a rear support provided at a rear portion of each bay; and mounting portions for mounting the cluster module in a vertical orientation in a rack assembly and in a horizontal orientation in a rack assembly. 
         [0017]    In accordance with embodiments of the present invention, a rack-mount cluster module is provided, comprising: a cluster module chassis comprising a plurality of bays, each bay configured to receive a computer; and at least one computer mounted in one of the bays, the computer comprising a computer chassis containing a main board; wherein the cluster module chassis is configured to be mounted in a rack assembly in a vertical configuration such that the main board is horizontally oriented and in a horizontal configuration such that the main board is vertically oriented. 
         [0018]    Other features and aspects of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the features in accordance with embodiments of the invention. The summary is not intended to limit the scope of the invention, which is defined solely by the claims attached hereto. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  shows a prior art computer rack. 
           [0020]      FIGS. 2A-2B  show a rack-based computer system, in accordance with embodiments of the present invention. 
           [0021]      FIG. 3  is a perspective view of a rack assembly, in accordance with embodiments of the present invention. 
           [0022]      FIG. 4  is a perspective view of a portion of the rack assembly with the rack frame removed, in accordance with embodiments of the present invention. 
           [0023]      FIG. 5  is an enlarged perspective view of a central portion of the front portion of the computer system, in accordance with embodiments of the present invention. 
           [0024]      FIGS. 6A-6B  are front perspective views of a computer, in accordance with embodiments of the present invention. 
           [0025]      FIG. 7  is a perspective view of the rear side of the computer, in accordance with embodiments of the present invention. 
           [0026]      FIG. 8  is a perspective front view of a computer system, in accordance with embodiments of the present invention. 
           [0027]      FIG. 9  is a perspective front view of an active chassis retainer, in accordance with embodiments of the present invention. 
           [0028]      FIGS. 10A-10B  are perspective front views of a passive chassis retainer, in accordance with embodiments of the present invention. 
           [0029]      FIGS. 11A-11B  are perspective views of an empty bay in a rack assembly, in accordance with embodiments of the present invention. 
           [0030]      FIG. 12  is a front cross-sectional view of a computer, in accordance with embodiments of the present invention. 
           [0031]      FIG. 13  is a perspective view of rack assembly containing a plurality of cluster modules, in accordance with embodiments of the present invention. 
           [0032]      FIGS. 14A-14D  are perspective views of a cluster module, in accordance with embodiments of the present invention. 
           [0033]      FIG. 15  is a perspective front view of a cluster module in a vertical orientation, in accordance with embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    In the following description, reference is made to the accompanying drawings which illustrate several embodiments of the present invention. It is understood that other embodiments may be utilized and mechanical, compositional, structural, electrical, and operational changes may be made without departing from the spirit and scope of the present disclosure. The following detailed description is not to be taken in a limiting sense, and the scope of the embodiments of the present invention is defined only by the claims of the issued patent. 
         [0035]      FIG. 2A  shows a rack-based computer system  200  in accordance with embodiments of the present invention.  FIG. 2B  is an enlarged view of a portion of the computer system  200 . The computer system  200  comprises a rack assembly  201  which provides the structural support for a plurality of computers  210  contained therein. 
         [0036]    The rack assembly  201  may comprise a vertically elongated, floor mounted cabinet assembly. The rack assembly  201  may comprise a rectangular internal rack frame  202  externally covered by removable enclosure panels  204 . An access door may be pivotally mounted on one or more sides of the rack assembly to provide access to the computers and other components (such as, e.g., routers, hubs, cabling, etc.) housed in the rack assembly  201 . In other embodiments, the enclosure panels and access doors may be omitted or may be integrally formed with the rack frame  202 . The rack assembly  201  may comprise a standard-sized rack, or may have different dimensions. In one embodiment, the rack assembly measures approximately 24″ wide, 40″ deep, and 74″ high. In the embodiment illustrated in  FIGS. 2A-2B , the rack assembly  201  comprises a front opening  212  and a rear opening  214 . Side panels  204 , front doors  206 , and rear doors  208  are provided for enclosing the computer system  200 . In the system  200  illustrated in  FIGS. 2A-2B , the rack assembly  201  is only partially filled with computers  210 , leaving room to add additional computers  210  into the system  200 . 
         [0037]    As can be seen in  FIGS. 2A-2B , the computers  210  are positioned in a side-by-side orientation. Thus, when viewing the computers  210  through the front opening  212 , two computers  210  can be seen positioned at each horizontal section of the rack assembly  201 . Each computer  210  includes its own horizontally-oriented main board and other components to form a computer. This is in contrast with conventional rack-based systems in which each horizontal section of the rack contains a single computer chassis containing a single horizontally-oriented main board. This is also in contrast with conventional blade-type computer systems which may include multiple vertically-oriented blades arranged side-by-side. 
         [0038]    In addition to the side-to-side arrangement of the computers  210 , the rack assembly  201  may also support computers in a back-to-back arrangement. Thus, another set of side-by-side computers  210  can be accessed from the rear opening  214  of the rack assembly  201 . The perspective view of the rear opening  214  would be similar to the perspective view of the front opening  212  shown in  FIG. 2A . Thus, four vertically arranged stacks of computers  210  may be provided in the computer system  200 . During operation, cooling air may be drawn through the computers  210  into a central air plenum positioned between the back sides of the computers  210  and then exhausted out of an exhaust port, such as top exhaust port  216 . 
         [0039]      FIG. 3  is a perspective view of the rack assembly  201  with front doors  206 , rear doors  208 , side panels  204 , and computers  210  removed. The illustrated rack assembly  201  comprises a rack frame  202 , which provides the main structural support for the various components of the computer system  200 . 
         [0040]      FIG. 4  is a perspective view of a portion of the rack assembly  201  with the rack frame  202  removed. In this figure, the internal support structure  220  can be seen. The internal support structure  220  is supported by the rack frame  202  and comprises a front pair of mounting members  232   a - 232   b  and a rear pair of mounting members  233   a - 233   b . The front mounting members  232   a - 232   b  are coupled to the rack frame  202  and support the front computer support plates  230   a - 230   d . The rear mounting members  232   b  are also coupled to the rack frame  202  and support the rear computer support plates  231   a - 231   d . The internal support structure  220  also comprises a plurality of rear supports  234 , which are positioned to abut the back sides of the computers  210  when the computers  210  are fully inserted into the rack assembly  201 . A first pair of rear supports  234   a - 234   b  are positioned to abut the back sides of the computers  210  in the front section of the rack assembly  201 , and second pair of rear supports  234   c - 234   d  are positioned to abut the back sides of the computers  210  in the back section of the rack assembly  201 .  FIG. 5  is an enlarged perspective view of a central portion of the front section of the computer system  200 . 
         [0041]    Although the terms “front” and “rear” are used to describe various components in the illustrated computer system  200 , it will be understood that these are relative terms used here for convenience. In the illustrated embodiment, the front section of the computer system  200  and the rear section of the computer system  200  are substantially identical, but oriented in opposite directions so that the front sides  601  of the computers  210  mounted in the front section can be accessed through the front opening  212 , and the front sides  601  of the computers  210  mounted in the rear section can be accessed through the rear opening  214 . The following text describes the front portion of the computer system  200 . However, it will be understood that the description may apply to the rear portion as well. 
         [0042]      FIGS. 6A-6B  are front perspective views of a computer  210  that can be mounted into the rack assembly  201 . The computer  210  may comprise a computer chassis  600  containing a main board  610  and other components, such as one or more power supplies  612 , hard drives  608 , removable media drives  609 , processors  624 , and expansion cards, contained within the computer chassis  600 . The chassis  600  may comprise a chassis top  602 , which may be removable to provide access to the components contained therein. An exemplary computer  210  is described in greater detail in the following U.S. provisional patent applications, the disclosures of which are incorporated by reference herein in their entireties: U.S. provisional patent application No. 60/568,969 entitled “INTERFACE ASSEMBLY”, filed May 7, 2004; U.S. provisional patent application No. 60/569,020 entitled “ELECTROMAGNETIC INTERFERENCE SHIELD FOR I/O PORTS”, filed May 7, 2004; and U.S. provisional patent application No. 60/569,019 entitled “DIRECTIONAL FAN ASSEMBLY”; filed May 7, 2004. 
         [0043]    A computer  210  may comprise any electronic system designed to perform computations and/or data processing. In some embodiments, the computer  210  comprises an electronic device having a central processing unit (CPU) and memory. The CPU and memory may be provided on a main board  610 , which, in turn, may be mounted to the computer chassis  600 . The basic circuitry and components used by a computer to function are generally either contained in or attached to the main board. The main board typically contains the system bus, processor and coprocessor sockets, memory sockets, serial and parallel ports, expansion slots, and peripheral controllers. This chassis  600  may comprise, for example, a housing that encloses all or portions of the main board  610  and components coupled thereto. Alternatively, the chassis  600  may comprise a minimal structure (such as, e.g., a tray or frame) which provides mechanical support for the main board  610 . Alternatively, the computer may comprise a printed circuit board (PCB) main board having exposed components without an enclosure. 
         [0044]      FIG. 6B  is a perspective view of the front side  601  of the computer  210  with the chassis top  602  removed to expose the main board  630  and other components contained within the computer chassis  600 . When the computers  210  are mounted in the rack assembly  201 , the front sides  601  of the computers  210  are exposed to a user facing the front opening  212  of the rack assembly  201 . As can be seen in  FIGS. 6A-6B , the front side  601  of the computer  210  exposes various components which a user may wish to access to operate or maintain the computer system  200 . These components may include, for example, one or more removable media drive ports, a mass storage device, and I/O connectors. The computer  210  may be provided with a front bezel which partially or fully covers the front of the computer  210 . This bezel may be removable or pivotally mounted to enable the bezel to be opened to provide access to the various components. The bezel may function to reduce the effect of electromagnetic interference (EMI), to minimize the impact of environmental factors, and to improve the aesthetic appearance of the computer  210 . In the embodiment illustrated in  FIGS. 6A-6B , the I/O connectors are exposed by an I/O connector opening  618  in the computer chassis  600 . The I/O connector opening  618  is covered by a movable I/O door  620 , which provides EMI shielding. 
         [0045]      FIG. 7  is a perspective view of the rear side  603  of the computer  210 . The rear side  603  of the computer chassis  600  may comprise a directional fan assembly  640 , a power port opening  632  for exposing a power connector of a power supply  612 , a power switch opening  634 , a power supply fan opening  636 , and a chassis connector  650 . In other embodiments, the rear side  603  may also include one or more additional apertures to accommodate other components, such as additional fans or I/O connectors, which may be to alternative designs of the computer  210 . 
       Chassis Retainer 
       [0046]      FIG. 8  is another embodiment of the rack-based computer system  200 , in which active chassis retainers  800  may be used to releasably retain the computers  210  in the rack assembly  201 .  FIG. 9  is an enlarged perspective view of an exemplary active chassis retainer  800  mounted to one side of the computer chassis  600 . In this embodiment, the chassis retainer  800  comprises a cantilevered flange  810  having a protruding portion  812  which mates with a corresponding recess  820  in the front support plate  230   d  when the computer  210  is fully inserted into the rack assembly  201 . The cantilevered flange  810  has an outward bias which urges the protruding portion  812  outward. The chassis retainer  800  may also comprise a release member  814  and a handle  816  that extend beyond the front face of the computer  210 . The user may push on the handle  816  to insert the computer  210  into the bay, or may pull on the handle  816  to retrieve the computer  210  from the bay, as will be described in greater detail below. 
         [0047]    When the computer  210  is fully inserted into an available bay in the rack assembly  201 , the outward bias of the flange  810  causes the protruding portion  812  to be received into the recess  820 . The engagement of the protruding portion  812  with the recess  820  may help to prevent the computer  210  from being inadvertently dislodged from the fully inserted position. This may also provide a tactile and audible feedback to the operator indicating that the computer  210  has been fully inserted into the bay. When the operator wishes to remove the computer  210  from the rack assembly  201 , the user may apply a lateral force onto the release member  814  opposing the outward bias of the flange  810 , thereby withdrawing the protruding portion  812  from the recess  820 . The user may then pull on the handle  816  to withdraw the computer  210  from the bay. 
         [0048]      FIGS. 10A-10B  are perspective views of the opposite side of the computer  210 . In accordance with some embodiments, a passive chassis retainer  840  may be used to retain the computer  210  in the bay of the rack assembly  201 . In the illustrated embodiment, the passive chassis retainer  840  comprises a flange  850  having a protruding portion  852  which mates with a corresponding recess  820  in the front support plate  230   c  when the computer  210  is fully inserted into the rack assembly  201 . In this case, the flange  850  has an inward bias which urges the protruding portion  812  away from the support plate  230   c . The I/O door  620  comprises a lip  854  having an angled portion  856 . When the I/O door  620  is in the open position, as shown in  FIGS. 10A-10B , the lip  854  does not engage the flange  850 . However, when the I/O door  620  is closed, the lip  854  engages the flange  850  to oppose the inward bias of the flange  850  and urge the protruding portion  852  outward. When the I/O door  620  is fully closed, the protruding portion  852  is received into the recess  820 , thereby preventing the computer  210  from being removed. Thus, the passive chassis retainer  840  is actuated by opening and closing the I/O door  620 . 
         [0049]    During use, when an operator wishes to insert a computer  210  into an available bay in the rack assembly  201 , the operator first opens the I/O door  620 , thereby allowing the protruding portion  852  to be withdrawn into the interior of the computer  210  due to the inward bias of the flange  850 . The computer  210  can then be inserted into the rack assembly  201 . Once the computer  210  is fully inserted, the I/O door  620  may be closed, thereby actuating the chassis retainer  840  and locking the computer  210  in the bay. To withdraw the computer  210 , the I/O door  620  is first opened, thereby allowing the natural bias of the flange  850  to pull the protruding portion  852  away from the recess  820 . The operator can then pull on the handle  816  and/or use the I/O door  620  as a handle to withdraw the computer  210 . 
         [0050]    In other embodiments, the I/O door  620  may be, for example, spring-loaded to provide a bias on the I/O door  620  urging the I/O door  620  towards the closed position. Thus, during insertion, an operator manually holds the I/O door  620  in the open position in order to release the flange  850 . Once the operator releases the I/O door  620 , the I/O door  620  will automatically close, thereby actuating the retainer  840 . 
         [0051]    In some embodiments, the protruding portion  852  may enable the computer  210  to be inserted even when the I/O door  620  is closed. In the embodiment illustrated in  FIGS. 10A-10B , the protruding portion  852  is cantilevered such that when the I/O door  620  is closed, thereby urging the flange  850  outwards, the protruding portion  852  can flex to allow the computer  210  to be received in the bay. When the computer  210  is inserted into the bay, the protruding portion  852  will bend inwards to clear the support plate  230   c . Once the protruding portion  852  reaches the recess  820 , the protruding portion  852  springs outward, thereby preventing the computer  210  from being withdrawn from the bay without first opening the I/O door  620 . 
         [0052]    In various embodiments, one or both types of chassis retainers  800 ,  840  may be used. The chassis retainer  800  is an active retainer, which automatically locks the computer  210  into the bay once the computer  210  is fully inserted. The chassis retainer  840  is a passive retainer, which is actuated by the opening and closing of the I/O door  620 . In the illustrated embodiment, the chassis retainer  800  is used on one side of the computer  210  and the door-actuated chassis retainer  840  is used on the opposite side. This can advantageously provide both active and passive mechanisms for retaining the computer  210  in the rack assembly  201 . In addition, the feedback from the active retainer  800  indicating that the computer  210  is fully inserted may be used as an indicator that the passive retainer  840  is in position to be actuated. In other embodiments, a single active retainer  800  on a single side of the computer  210  may be used. In other embodiments, two or more active retainers  800  may be used with at least one retainer  800  on each side. Similarly, in other embodiments, one or more passive retainers  840  may be used. 
         [0053]    In accordance with various embodiments, the chassis retainers  800 ,  840  may provide advantages over conventional designs. In many conventional computer systems, the computers are attached to the rack assembly using thumbscrews which pass through flanges extending from the sides of the front of the computer and mate with openings provided on the rack assembly. When installing or servicing large numbers of computers, the screwing and unscrewing of these thumbscrews can be a tedious and time-consuming process. The use of chassis retainers  800  and  840  can enable the computers to be very rapidly retained and released from the rack assembly. In addition, the chassis retainer  800  can be easily manufactured and installed onto a variety of computer chassis designs. 
       Computer Support Rails 
       [0054]    In accordance with embodiments of the present invention, the rack assembly  201  may comprise a support rail system for supporting the computers  210  mounted in the rack assembly  201 .  FIGS. 11A-11B  are perspective views of an empty bay  1100  in the rack assembly  201 . In these figures, it can be seen that the support plates  230  comprise a plurality of support flanges  250 . These support flanges  250  may be created by forming a U-shaped cut  252  in a first support plate  230   d  and then bending the portion of metal inside of the U-shaped cut  252  such that the portion defines a plane substantially perpendicular with the plane defined by the remainder of the support plate  230   d . This bent portion forms the support flange  250 , which provides a support surface for one side of a computer  210  being mounted in the rack assembly  201 . Similarly, a second support flange  250  may also be formed in a second support plate  230   c  opposite the bay  1100  from the first support plate  230   d . When a computer  210  is inserted into the bay  1100 , a first side of the computer  210  is supported by the first support flange  250  and a second side of the computer  210  is supported by the second support flange  250 . 
         [0055]    In accordance with some embodiments, each support flange  250  may serve to support a first computer  210  on one side and may further serve to abut a second computer  210  positioned adjacent the first computer  210  in order to securely retain the second computer  210  in place. This can be seen in  FIGS. 11A-11B , which shows a first computer  210   a  positioned below the empty bay  1100  and a second computer  210   b  positioned above the empty bay  1100 . Here, the first support flange  250   a  contacts the top of the first computer  210   a  to prevent the first computer  210   a  from being inadvertently dislodged upwards out of the desired location. In addition, the first support flange  250   a  would provide upward support for any computer  210  that was inserted into the bay  1100 . Similarly, the second support flange  250   b  currently provides upward support for the second computer  210   b , and could provide a downward retaining support for any computer  210  inserted into the bay  1100 . 
         [0056]    In accordance with various embodiments, the support flanges  250  may provide an inexpensive structure for reliably supporting the computers  210  in the rack assembly  201 . In conventional systems, each horizontal support rail in a rack assembly is manually attached to the vertical supports of the rack frame. Although this may provide flexibility in accommodating differently sized computer chassis, the assembly process can be very time-consuming and does not facilitate rapid deployment of large numbers of computer systems. In contrast, the support plates  230  incorporating the support flanges  250  can be very rapidly and inexpensively manufactured and installed into the rack assembly  201 . Using the illustrated embodiment, the support rails for all of the computers for a section of a rack assembly or for an entire side of a rack assembly can be installed by attaching a pair of support plates  230  to the rack frame  202 . 
         [0057]    If it is desired to use differently sized computer chassis in the rack assembly  201 , the support plates  230  can be quickly removed and replaced with a support plate  230  having support flanges  250  formed with the desired spacing. When the support plates  230  and support flanges  250  are formed from single sheets of metal, the cost of replacing the support plates  230  may be negligible relative to the ease of assembly. 
       Computer Chassis 
       [0058]    In accordance with some embodiments, the computer  210  comprises a computer chassis  600  having an improved design and form factor. As described above, conventional rack-based computer system manufacturers adhere to common computer chassis designs which are configured to extend the entire interior width of an EIA standard 19″ rack. For example, the interior of a standard 44 U rack is approximately 19″ wide, approximately 40″ deep, and approximately 77″ tall. In order to increase the number of computers that can be mounted in a single rack, these manufacturers typically reduce the height of the chassis but maintain the width. This results in a flat, wide, “pizza box”-type chassis configuration. A typical 1 U server may have a height of approximately 1.7″, a width of approximately 17″, and a depth of approximately 24″. While this chassis form factor may be suitable for housing wide, flat components, it is not convenient for containing tall components. In addition, with an exterior height of just 1.7″, any components contained within the chassis may substantially block the cooling airflow through the chassis. Although 2 U, 3 U, or 4 U height chassis are available, these conventional systems typically maintain the same width as the conventional 1 U server. 
         [0059]      FIG. 12  shows a cross-sectional block diagram of a computer  210  in accordance with embodiments of the present invention. The computer  210  comprises a computer chassis  600  having a height, H c , of approximately 3.1″, a width, W c , of approximately 12.15″, and a depth of approximately 16.7″. In this embodiment, the computer chassis has a width-to-height ratio of approximately 3.9. A conventional 1 U rack-mount server may have a width-to-height ratio of approximately 10. Even a 2 U rack-mount server may have a width-to-height ratio of greater than 4.9. 
         [0060]    In addition to having a width-to-height ratio less than the conventional ratio, the computer chassis  600  has a width that is substantially less than the standard EIA 19″ rack-compliant computer chassis. As shown in  FIG. 12 , the computer chassis  600  has a width that is only slightly larger than the width of the main board  630  contained therein. For example, in  FIG. 12 , the main board  630  comprises a standard EATX (“extended ATX”) motherboard having a width, W M , of just under 12″. Thus, the main board  630  fills substantially the entire width of the computer chassis  600 . 
         [0061]    In conventional rack-mount computers, many of the various computer components, such as the hard drives, removable media drives, and power supply, are positioned adjacent to the main board. In the computer  210 , because the main board  630  consumes substantially the entire interior width of the computer chassis  600 , there is no room adjacent to the main board available for the placement of additional components. In accordance with embodiments of the present invention, due to the increased height of the computer chassis  600 , these components may be mounted above the main board  630 . 
         [0062]    Another advantage of utilizing a taller form factor computer chassis  600  is that processors  624  having tall heat sinks  626  may be used, as shown in  FIG. 12 . Tall heat sinks  626  may comprise a plurality of heat-conducting fins that draw heat away from the processors  624  and onto the fins, where the heat can be drawn away by the cooling air flowing past the fins. Increasing the height of the heat sinks  626  may improve the heat sinks&#39; ability to cool the processors  624 . 
         [0063]    It may be desirable to position large computer components, such as the power supply  612 , above the main board  630  but laterally adjacent to the processors  624  and heat sinks  626 . As a result, cooling air which flows front-to-back (i.e., enters the front of the computer  210  and exits out of the back of the computer  210 ) or back-to-front (i.e., enters the back of the computer  210  and exits out of the front of the computer  210 ) will flow past the processors  624  and heat sinks  626  without being impeded by the large components, such as the power supply  612 . 
         [0064]    As shown in  FIG. 2A , computers  210  having these form factors may be mounted in a rack assembly  201  in a side-by-side and back-to-back configuration. In other words, these computers  210  may be mounted such that the front half of the rack assembly  201  supports two stacks of computers  210  and the back half of the rack assembly  201  support another two stacks of computers  210 . 
         [0065]    In accordance with other embodiments, a computer  210  having the computer chassis  600  as described above can be mounted into a standard 19″ rack.  FIG. 13  shows a computer system  900 , comprising an EIA standard 19″ rack assembly  902  and a plurality computers  210 , in accordance with embodiments of the present invention. The rack assembly  902  may have, e.g., an interior measuring approximately 19″ wide, approximately 40″ deep, and approximately 77″ tall. In this embodiment, the rack assembly  902  contains a plurality of cluster modules  910   a - 910   f , each cluster module  910  containing a plurality of computers  210 . These computers  210  are oriented vertically, in contrast with the horizontal mounting of computers  210  shown in  FIG. 2A . 
         [0066]      FIG. 14A  shows a perspective view of an empty cluster module chassis  920 . The cluster module chassis  920  comprises a plurality of computer bays  922  and a plurality of rack-mountable flanges  924 . The cluster module chassis  920  can be mounted in the rack assembly  902 , for example, by attaching the flanges  924  to vertical supports in the rack assembly  902  using thumbscrews. Each cluster module chassis  920  may, for example, be formed of sheet metal and be 12.25″ tall, 17.5″ wide, and 18.5″ deep. Accordingly, the cluster module  910  containing a plurality of computers  210  may be mounted in a standard 19″ rack. 
         [0067]      FIGS. 14B-14C  are perspective views of a cluster module chassis  920  filled with computers  210 . In  FIG. 14C , one computer  210  is shown partially removed.  FIG. 14D  shows a perspective rear view of the cluster module  910 . In this view, it can be seen that the cluster module chassis  920  may comprise a rear support  934 , similar to the rear support  234  described above and in greater detail in U.S. provisional patent application No. 60/568,969 entitled “INTERFACE ASSEMBLY,” filed May 7, 2004, the disclosure of which is incorporated herein in its entirety. 
         [0068]    In the computer system  900 , shown in  FIG. 13 , the rack assembly  902  is filled with cluster modules  910   a - 910   f . In other embodiments, one or more cluster modules  910  may be mounted in the rack assembly  902  adjacent to computers having conventional form factors, such as, e.g., 19″ wide 1 U servers. In this way, the computers  210  can be utilized in a mixed-computer environment without requiring installation of dedicated rack assemblies  201 . 
         [0069]    In accordance with other embodiments of the present invention, the cluster module  910  may be mounted in a rack in a vertically-oriented configuration  910 ′, as shown in  FIG. 15 . This cluster module  910 ′ may be substantially similar or identical to the cluster module  910  shown in  FIGS. 14A-14D , but is configured to mounted in a rack in a vertical orientation, such that the computers  210  contained therein are horizontally-oriented when deployed. The cluster module  910 ′ may comprise a cluster module chassis  920 ′, similar to cluster module chassis  920 , but with the flanges  924  for attachment with the rack assembly removed. This cluster module  950  may be installed in a rack assembly similar to rack assembly  201 , but without the support flanges  250  for each individual computer  210 . Thus, the same cluster module  910  can be deployed in both horizontal and vertical orientations, enabling the cluster module  910  to be used in a wide variety of rack assembly configurations. 
         [0070]    While the invention has been described in terms of particular embodiments and illustrative figures, those of ordinary skill in the art will recognize that the invention is not limited to the embodiments or figures described. For example, many of the embodiments described above refer to the computer systems being utilized as part of a server farm. In other embodiments, the computer systems may be used for other purposes, such as, for example, storage arrays. 
         [0071]    The figures provided are merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. The figures are intended to illustrate various implementations of the invention that can be understood and appropriately carried out by those of ordinary skill in the art. 
         [0072]    Therefore, it should be understood that the invention can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is not intended to be exhaustive or to limit the invention to the precise form disclosed. It should be understood that the invention can be practiced with modification and alteration and that the invention be limited only by the claims and the equivalents thereof.