Abstract:
An I/O subsystem for providing a high density modular input/output package in a data processing system. The I/O subsystem includes an enclosure having a midplane assembly in the center portion. The enclosure includes electrical components including redundant power supplies, air moving units and DASD carriers having DASD drives assemblies therein in the front portion of the enclosure, and planar boards having PCI card assemblies slidably mounted thereon in the rear portion of the enclosure. The mid plane includes multiconductor power buses for distribution of power from the power supplies to the electrical components of the I/O subsystem.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to high density arrangement of elements in a single package, and more particularly relates to high density arrangement of a modular Input/Output (I/O) package in a data processing system.  
           [0002]    Packaging inefficiency in the area of I/O has previously been identified by others, and an attempt has been made to create an improved structure. However, the resulting efforts have only moderately improved density and in many cases have resulted in the application of unique I/O cards as opposed to the use of standard PCI adapter cards.  
           [0003]    U.S. Pat. No. 5,672,509 issued Jun. 9, 1987 to Speraw for AIR COOLING ASSEMBLY IN AN ELECTRONIC SYSTEM ENCLOSURE discloses an air cooling assembly in a system enclosure for cooling a plurality of logic module cassettes located in the system enclosure.  
           [0004]    U.S. Pat. No. 5,317,477 issued May 31, 1994 to Gillett for HIGH DENSITY INTERCONNECTION ASSEMBLY discloses a high density computer interconnection assembly in which a plurality of flat packages are slidably mounted along a rack in a frame, an interconnection circuit board at right angles and connected to components in the flat packages, and memory cards coupled to the opposite side of the circuit board.  
           [0005]    U.S. Pat. No. 6,025,989 issued Feb. 15, 2000 to Ayd et al. for MODULAR NODE ASSEMBLY FOR RACK MOUNT MULTIPROCESSOR COMPUTER discloses a modular node assembly wherein a removable chassis having disk drives, power supply, and a fan is removably mounted in a logic chassis having processor cards, I/O cards and memory cards.  
           [0006]    U.S. Pat. No. 6,137,684 issued Oct. 24, 2000 to Ayd et al. for CAMMING MECHANISM FOR JOINING MODULAR ELECTRONIC ENCLOSURES discloses a camming and latching mechanism for locking a removable chassis having disk drives, power supply, and a fan into a logic chassis having processor cards, I/O cards and memory cards.  
         SUMMARY OF THE INVENTION  
         [0007]    I/O and storage devices are key components in any server. The overhead required to employ these devices in a server greatly affects the resulting physical size, cost and availability of a server. The present invention has enabled a single enclosure of I/O and storage hardware to replace what has been approximately three enclosures of a similar physical size in previous product offerings, with the single enclosure having improved fault tolerance over the multiple enclosure approach. The single enclosure approach reduces cost and component count appreciably.  
           [0008]    A unique packaging and subsystem structure has been invented that makes it possible to contain, power, cool and maintain concurrently (hot plug) a large amount of high performance I/O and storage hardware in a very compact space in a low cost fashion with a clean and neat physical appearance. This structure has components arranged so that all parts in the enclosure can be serviced without sliding out or removing the enclosure from the system. The I/O and storage hardware contained within the structure includes:  
           [0009]    20 full length/full power Peripheral Component Interconnect (PCI) cards;  
           [0010]    2 high bandwidth I/O planars each with a dual host connection;  
           [0011]    4 imbedded Small Computer System Interface (SCSI) controllers (2 contained on each I/O planer);  
           [0012]    16 one inch high speed SCSI hard drives; and  
           [0013]    4 Hard Drive Backplanes.  
           [0014]    It is an object of the present invention to use a modular puzzle like structure that packages components within fault containment regions in a hierarchical fashion that enables concurrently maintaining the most failure prone components without disturbing any other component in the unit, and then maintaining a second level of less failure prone fault containment regions without affecting other such regions in the unit.  
           [0015]    It is a further object of the present invention to use cassettes to house PCI cards enabling simple insertion and extraction of I/O adapters.  
           [0016]    It is a further object of the present invention to use the physical positioning of the 2nd level fault containment regions with respect to one another to enable the use of only two centric power supplies and four air moving devices to power and cool all I/O and storage hardware in the enclosure with complete power and cooling hardware fault tolerance (redundancy). The use of high speed instantaneous current limiting hardware on the 2nd level and 1st level fault containment regions is also an employed technique that enables this.  
           [0017]    It is a further object of the present invention to use service controllers packaged internal to the two redundant power supplies so that the service control function is fully redundant, fault tolerant and concurrently maintainable. This technique enables the higher density achieved by eliminating service controls on each 2nd level fault containment region. The use of redundant service controllers improves availability considerably, and assures that a controller is always available to light the amber LED&#39;s (Light Emitting Diodes) that are carefully placed throughout the unit to identify components that require replacement.  
           [0018]    It is a further object of the present invention to use the association of elements with respect to one another to enable proper airflow over the components without a significant amount of dedicated space for air flow management. Adequate air flow is maintained over all components even in the case of an air moving device failure or temporary removal of a faulty element that must be replaced. Air is pulled through the power supply units and disk drives by the air moving devices and is exhausted across the components on the planar board through the PCI adapter cards.  
           [0019]    It is a further object of the present invention to use simple air moving devices that physically contain only a simple motor and wheel, and rely on brushless/sensorless drive electronics contained within the power supplies. This technique enables the air moving devices to be buried within the unit, behind 2nd level fault containment regions due to the very low air moving device failure rate that this technique yields.  
           [0020]    It is a further object of the present invention to package all of the I/O and storage components and the supporting power and cooling hardware with a minimum number of wire type cables, thereby providing a clean and neat appearance and aiding ease of service. All of the units in the drawer blind plug through the use of autodocking connectors easing service operations.  
           [0021]    It is a further object of the present invention to use a completely passive compact mid-plane structure in the center of the enclosure to interconnect the 2nd level fault containment regions. The completely passive nature of this element provides the required level of availability for this element, since it represents the only potential single point of failure in the subsystem.  
           [0022]    It is a further object of the present invention to use a 4 EIA high overall enclosure that mounts in a standard 24″ EIA rack, thereby providing system level packaging flexibility.  
           [0023]    It is a further object of the present invention to use an enclosure level power and service control interface that consists of 4 identical compact cables, which plug directly into the front of the power supplies. These interfaces provide cross redundant connections to the entire subsystem very cost effectively, with the capability of concurrently servicing any of the cables. Each of the interface cables contain 350 VDC power and a full duplex differential RS-422 control interface.  
           [0024]    It is another object of the present invention to provide a component arrangement that enables servicing all parts in the enclosure without sliding the unit out or removing it from the system.  
           [0025]    It is another object of the present invention to provide a component arrangement that enables a full compliment of fault identification LED&#39;s (1-2 per serviceable unit), with all of the LED&#39;s being physically packaged on the components of the unit as opposed to on a dedicated unit for LED&#39;s, and with all of the LED&#39;s being visible from the front and rear of the enclosure with the enclosure fully installed in the system.  
           [0026]    It is another object of the present invention to provide an air moving device with a unique latching and retention mechanism that enables it to be concurrently maintained after removing a DASD backplane assembly. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]    These and other objects will be apparent to one skilled in the art from the following detailed description of the invention taken in conjunction with the accompanying drawings in which:  
         [0028]    [0028]FIG. 1 is a block diagram of the I/O subsystem of the present invention;  
         [0029]    [0029]FIG. 2 is a partially exploded front view of an enclosure for containing the I/O subsystem of FIG. 1, and showing a fully inserted first power supply module and showing a second power supply module, air moving device and a 4-pack DASD carrier exploded;  
         [0030]    [0030]FIG. 3 is a partially exploded front view of the enclosure showing the two power supplies fully seated in the enclosure, a 4-pack DASD carrier, a front cover, and a DASD filler exploded from the enclosure with a DASD drive assembly and a DASD blank cartridge exploded from the 4-pack DASD carrier;  
         [0031]    [0031]FIG. 4 is a partial front view of the enclosure of the present invention showing the power supplies and DASD drive assemblies fully seated in the enclosure;  
         [0032]    [0032]FIG. 5 is a front view of the midplane of the present invention;  
         [0033]    [0033]FIG. 6 is rear view of the midplane of the present invention;  
         [0034]    [0034]FIG. 7 is a partially exploded rear view of the enclosure of the present invention showing an enclosure for the I/O subsystem with one of the planar boards of the invention removed;  
         [0035]    [0035]FIG. 8 is a partially exploded rear view of the enclosure of the present invention having two planar boards fully inserted into the enclosure and showing a PCI cassette and a PCI filler cassette exploded;  
         [0036]    [0036]FIG. 9 is a section view of the enclosure showing the air flow through the enclosure;  
         [0037]    [0037]FIG. 10 is a slightly rotated side view looking from the back of the air moving device fully seated and latched in place; and  
         [0038]    [0038]FIG. 11 is a slightly rotated side view looking from the front of the air moving device fully seated and latched in place. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0039]    [0039]FIG. 1 is a block diagram of the I/O subsystem  10  of a data processing system. The data processing system may be any of IBM pSeries p690, p670, or p655 and follow-on servers available from International Business Machines Corporation. The I/O subsystem  10  of the present invention may include two planar boards  14 A and  14 B. Each planar board includes a number of Peripheral Component Interconnect (PCI) cards  15  for connection into the data processing system, as is well known in the art. For example, planar board  14 A includes cards PCI 1 -PCI 10 , while planar board  14 B includes cards PCI 11 -PCI 20 . Each planar board  14  is connected to a pair of DASD backplanes  16 A and  16 B, and each backplane  16  includes 4 DASD devices  20 . Thus, for instance, planar board  14 A connects to 8 DASD devices (DASD 1 -DASD 8 ), and planar board  14 B connects to 8 DASD devices (DASD 9 -DASD 16 ). Each DASD backplane  16  also includes terminators  23 .  
         [0040]    Redundant power supplies  21  and  22  supply power over power busses  25  in a midplane  28  between the planar boards  14 A- 14 B and the back planes  16 A- 16 B. Power is supplied to a power and Light Emitting Diode (LED) control  30  for each board, which controls power to its planar board  14 . Each backplane  16  also includes a power control  32  which is connected to a power bus in the midplane  28 , and controls power to the backplane. The planar board  16  is protected by a soft switch  12 , as well as each of the PCI cards  15 . In the backplanes  16 , each of the DASD devices  20  and the terminators  23  are protected by a soft switch  12 . The soft switches  12  are fully disclosed in U.S. patent application Ser. No. ______ (Attorney docket number POU920020120US1) owned by the assignee of the present invention, which application is incorporated herein by reference.  
         [0041]    In each planar board  14 , a Small Computer System Interface (SCSI) module  34  is provided to provide the protocols for communication between the DASD devices and the PCI bus, as is well known. Backplane assemblies, to be explained, are designed to carry up to 4 DASD devices  20 , and are designed to be hot plugged. The SCSI Environmental Services (SES) modules  36  on the planar boards  14  will assert the SCSI reset line during hot removal and hot plug to minimize disruption on the SCSI bus. The hot plug reset function will be controlled by short, medium and long pins on interposer connectors in the carrier assemblies, as is well known.  
         [0042]    Each planar board  14  includes a riser  40  to provide cable connectors for connecting the I/O subsystem  10  to processors of the data processing system, as is well known. Each planar board  14  includes a speedwagon  42  which is a processor-to-PCI bridge module. The end of the planar board  14  includes a plurality of LEDs  44 , two for each PCI card  15  and the riser  40  for indicating the status of its respective card or riser. Each DASD backplane  16  also includes 10 LEDs  44  for indicating the status of its respective drives and air moving devices mounted behind them. The LEDs are visable through lightpipes.  
         [0043]    [0043]FIG. 2 is a partially exploded front view of an enclosure  50  for containing the I/O subsystem of FIG. 1. FIG. 2 shows the first power supply module  21  fully inserted into the enclosure  50 , and the second power supply module  22 , an air moving device  52  and a 4-pack DASD carrier  54  exploded. The power supply modules  21  and  22  have connectors  56  at the rear for plugging into the midplane  28  (as will be explained). The air moving device  52  is a centrifugal type blower which takes air in from the bottom and discharges air from openings  58  in the side of the air moving device. The air moving device  52  further includes a latch  60  at the bottom with an actuation device  62  in the front. The top of the front of the enclosure  50  is divided into four bays by three stiffeners  64 , and the bottom of the enclosure  50  is divided into two bays by a stiffener  66 . The top and bottom parts of the front portion of enclosure  50  are divided by a horizontal stiffener  68 . Each of the top four bays are sized to receive a 4-pack DASD carrier  54 . Four air moving devices  52  are pushed into the four top front bays and latched into place by the latch  60  on each air moving device  52 . Connectors in the air moving device  52  and on enclosure  50 , to be discussed in connection with FIG. 5, are mated to supply power and controls to the air moving device. The four DASD carriers  54  are then slidably located into the four top bays and seated such that connectors  63  on the back of the DASD carriers  54  are mated with connectors in the enclosure  50 , to be discussed in connection with FIG. 5. The air moving units  52  are sized to pass under their connectors and pass over connectors in the midplane  28  which mate with the connectors  63  of the DASD carriers  54 .  
         [0044]    [0044]FIG. 3 is a partially exploded front view of the enclosure  50  showing the two power supplies  21  and  22  fully seated in the enclosure  50 . A DASD carrier  54 , a front cover  70 , and a DASD filler  72  are shown exploded from the enclosure  50 . Each DASD carrier  54  includes a backplane  16  which carries up to four DASD drive assemblies  20 . When one of the DASD assemblies is not used, a DASD blank cartridge  76  is used to preserve cooling air flow. If a DASD carrier  54  is not used, a DASD filler  72  is used to cover its empty bay to preserve cooling air flow. Finally, a front cover  70  is placed over the front of the enclosure.  
         [0045]    [0045]FIG. 4 is a partial front view of the enclosure  50  showing the power supplies  21  and  22  and DASD carriers  54  carrying the DASD drive assemblies  20  fully seated in the enclosure  50 . The front cover  70  has been removed in FIG. 4 to show the arrangement of the DASD drive assemblies  20 . The front of the power supplies  21  and  22  have a row of LEDs  44  for showing the status of the components in the power supplies. Also, the front of the power supplies have pluralities of cooling air holes  80 . Each DASD drive  20  includes a pair of light pipes  82  to show the status of the respective DASD drive  20 . These light pipes  82  are visible when the cover  70  is in place. The cover  70  also has cooling air holes to allow cooling air to be drawn into the enclosure  50  to cool the DASD drives  20 . The top of the enclosure  50  also has slots  84  to allow cooling air to be drawn over the DASD drives  20 , and to allow a place to grasp the DASD arriers  54  for easy removal. The enclosure  50  is a standard sized 4 high EIA enclosure and includes flanges  86  for securing the enclosure into a standard 24″ EIA rack.  
         [0046]    Four power connectors  81  in the front of the power supplies  21  and  21  provide power and service control interfaces that consists of four identical compact cables (not shown), which plug directly into the connectors  81  in the front of the power supplies. These interfaces provide cross redundant connections to the entire subsystem, with the capability of concurrently servicing any of the cables. Each of the interface cables contain 350 VDC power and a full duplex differential RS-422 control interface.  
         [0047]    [0047]FIG. 5 is a front view of the midplane  28 . There are four connectors  90  on the front side of the midplane  28  for connection with mating connectors  63  on the rear of the DASD carriers  54 . Each connector  90  has guide blocks  92  for blind mate to connectors  63  on the rear of the DASD backplanes  16 . The connectors  90  are connected to the midplane  28  by flex conductors  96 . Mounted above the front of the midplane  28  are connectors  98 , each of which connect to two air moving devices  52 . Each power supply  21  and  22  power two air moving devices  52 , but power supply  22  handles the first and third air moving devices, and power supply  21  handles the second and fourth air moving devices  52 , so that cooling air is always being moved on both sides of the enclosure  50 , even if one of the power supplies should fail. As mentioned in connection with FIG. 2, the air moving devices  52  are sized to pass above the connectors  90 . In the lower part of the front of the midplane  28  are power  100  and signal  101  connectors to mate with power and signal connectors  56  (see FIG. 2) on the back of power supplies  21  and  22 . The midplane connectors  100  include alignment pins  102  (see also FIG. 6) to align the connectors  56 . The connectors for the air moving device on the back of the power supplies  21  and  22  are allowed to float for final alignment, as is well known.  
         [0048]    [0048]FIG. 6 is a rear view of the midplane  28 . The rear of the midplane  28  includes a connector assembly having power  104  and signal connectors  106  for mating with power and signal connectors  157  on the back of the planar boards  14 A and  14 B of FIG. 1, as will be explained further in relation to FIGS. 7 and 8. The power connectors  104  include alignment pins  108  to align floating connectors on the back of the planar boards  14 A and  14 B.  
         [0049]    [0049]FIG. 7 is a partially exploded rear view of the enclosure of FIG. 1. FIG. 7 shows the enclosure  50  with one of the planar boards  14 A removed, and planar board  14 B fully seated within the enclosure  50 . The riser  40  of the planar board  14 A is exploded, and a riser  40  is seated in the middle of the planar board  14 B. The planar boards  14  includes rail connectors  152  onto which the PCI card assemblies (to be discussed in connection with FIG. 8) may be latched. A stiffener  154  is provided between the planar cards  14 A and  14 B to form two bays for the planar boards  14 . A planar stiffener  156  is also provided on each planar board  14  to help guide the planar board  14  into its bay and provide support for PCI cassettes  158  and  160 . Power and signal connectors  157  are provided on the back (the inmost edge) of each planar board  14 .  
         [0050]    [0050]FIG. 8 is a partially exploded rear view of the enclosure  50  having the two planar boards  14 A and  14 B fully inserted into the enclosure  50 . A PCI card assembly  158  is slidably engageable with one of the rail connectors  152  on the planar card  14 . The PCI card assembly  158  includes a PCI card  15  of FIG. 1. The PCI card assembly is constructed in accordance with U.S. patent application Ser. No. 10/194,799 (Attorney Docket Number POU920020048US1) owned by the assignee of the present invention, and incorporated herein by reference. Where there is no PCI card  15  to be installed, a PCI filler cassette  160  is located in its slot and latched into place. The PCI filler cassette  160  has the same air resistance characteristics as a regular PCI card assembly  158  so that the flow of cooling air (to be explained) is not changed by the absence of a PCI card.  
         [0051]    [0051]FIG. 9 is a section view of the enclosure  50  showing the air flow through the enclosure  50 . The air moving devices  52  are positioned in the enclosure  50  above the connectors  90  and behind the DASD carriers  54 . Each air moving device  52  is placed on a secondary floor  168  which is raised from the horizontal stiffener  68 . As previously mentioned, the air moving device  52  is a centrifugal blower whose input is at the bottom of the unit, and whose output is in the side  58  of the unit. Connectors  162  are attached to the top wall of the enclosure  50  to connect with connectors at the rear of the air moving devices  52 , and cables  164  are connected between the connectors  98  and  162  for supplying power to the air moving devices  52 . The secondary floor  168  has perforations (see FIG. 11) to allow air to pass through the cover  70 , around the DASD drives  20 , through the DASD carriers  54 , through perforations  170  (see FIG. 11) in the secondary floor  168  and into the input in the bottom of the air moving device  52 . Air is also drawn through the power supplies  21  and  22 , and into the bottom of the air moving device  52 . Air is expelled through the sides openings  58  of the air moving unit  52  and is deflected downwardly by a flap device  175  which also prevents re-circulation with a failed blower. The cooling air then passes around the PCI card assemblies  158  and flows out at the rear of the enclosure  50 . A wire cage device  178  is provided at the rear of the air moving device  52  and flap device  175  for safety purposes. A handle  180  is provided on the front of the air moving device  52  to make positioning the air moving device  52  on top of the secondary floor  168  easier.  
         [0052]    [0052]FIG. 10 is a slightly rotated side view looking from the back of the air moving device  52  which is fully seated and latched in place. The stiffeners  64  have holes  185  for allowing air to freely move between the top front bays of the enclosure  50 .  
         [0053]    [0053]FIG. 11 is a slightly rotated side view looking from the front of the air moving device  52  fully seated and latched in place. The horizontal stiffener  68  has slots  188  therein for letting cooling air freely move between the top and the bottom of the front portion of the enclosure  50 . The connector  94  for the DASD backplanes  16  is shown in FIG. 11, but the DASD carrier  54  is not shown, for simplicity.  
         [0054]    While the preferred embodiment of the invention has been illustrated and described herein, it is to be understood that the invention is not limited to the precise construction herein disclosed, and the right is reserved to all changes and modifications coming within the scope of the invention as defined in the appended claims.