Abstract:
For achieving installation of disk drives at high density, as well as, a large capacity and a high speed of the disk array apparatus, the disk array apparatus comprises disk drives, a box containing a large number of the disk drives in a direction of thickness thereof, wherein a throttle of flow passage, which combines a sour absorbing material in common, is provided above the disk drives in the downstream side of the disk array apparatus.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a disk array apparatus.  
         [0002]     In the disk array apparatus, the disk drives of a magnetic-type or an optical-type are contained within a housing, a large number thereof, so as to improve the reliability in data reservation. Those disk array apparatuses are connected through a high-speed network for exclusive use thereof, such as, applying a light therein, for example, wherein they are operated by means of management software, to be used in the form of, SAM (Storage Area Network), NAS (Network Attached Storage), or an independent RAID (Redundant Array of Inexpensive Disks), for example.  
         [0003]     Each of those disk drives, to be installed into those disk array apparatuses, is built up with a disk main body, comprising a magnetic disk, a drive motor, an actuator, etc., within an inside thereof, and connectors for use of electronic parts for control, etc. Main heat-generation sources in the disk drive include the drive motor, the actuator, and the control-use electronic parts, in the form of a LSI. Heats generated from those parts are cooled down with an aid of cooling wind generated by a cooling fan, which is attached on the housing of the disk array. If cooling capacity is deteriorated, then temperature of the disk drive goes up, and thereby generating unevenness among the plural number of disk drives; therefore, there is a possibility that it causes erroneous operations or deteriorates the reliability thereof.  
         [0004]     For example, if there is the unevenness in temperature among the disk drives, there is caused a shit in timing of the electronic parts; i.e., a possibility of causing defects in the operation of accessing from the controller to the disk drive, or generating a delay in the time for data transmission. Also, if temperature goes up in the disk drive, deterioration is caused ion a lubrication layer pasted upon the disk surface, and therefore the disk can be damaged, easily.  
         [0005]     Also, the magnetic disk, the drive motor, or the actuator, etc., included within an inside of the disk drive, defines an operating portion, and also defines a noise generating portion, at the same time. When installing the disk drives, each having such the noise source, by a large number thereof, then it is of course to increase the noises generated therefrom. Also, even noises cannot be neglected, which are generated from the fan for driving an air-flow within the disk array apparatus.  
         [0006]     In this manner, within the disk array apparatus, there are two (2) problems to be dissolved, i.e., of obtaining an equal cooling of the dirk drives, and also of silencing the noises of the disk drives and an apparatus.  
         [0007]     With the conventional disk array apparatus, mounting the disk drives and the controller circuit within the same surface on a board, it is already know to provide an air-guide plate, thereby dividing the cooling flow passages for the disk drives and the controller circuit (please see the following Patent Document 1).  
         [0008]     Or, with the conventional disk array apparatus, a measure is made of separating the flow passage, including the disk drives therein, and the flow passage, including the controller circuit therein, so as to equalize the cooling therebetween (please see the following Patent Document 2).  
         [0009]     Further, with the conventional disk array apparatus, there is already disclosed the structure of disposing the disk drives in a zigzag manner (please see the following Patent Document 3).  
         [0010]     Also, with the magnetic disk apparatus, there is already disclosed a cooling controller plate for increasing the velocity of winds passing by the side of a printed board (please see the following Patent Document 4).  
         [0011]     Patent Document 1: Japanese Patent Laying-Open No. Hei 9-274791 (1997);  
         [0012]     Patent Document 2: Japanese Patent Laying-Open No. 2001-338486 (2001);  
         [0013]     Patent Document 3: Japanese Patent Laying-Open No. Hei 5-54626 (1993); and  
         [0014]     Patent Document 4: Japanese Patent Laying-Open No. 2001-344961 (2001).  
         [0015]     With the conventional technology described in the Patent Document 1, since the disk drives and the controller are mounted on the same board, therefore the number is restricted of the disk drives, which can be installed therein. Also, there is no problem of equalizing the temperature distribution among the disk drives.  
         [0016]     With the conventional technology described in the Patent Document 2, though the disk drives and the controller are mounted on the same board, however there is no problem of equalizing the temperature distribution among the disk drives when a plural number of the disk drives are installed aligning with the flow direction.  
         [0017]     With the conventional technology described in the Patent Document 3, although flow resistance is increased, however since acceleration is made upon mixing of the cooling airs flowing on side surfaces of the disk drives, therefore an improvement can be obtained on the cooling characteristics of the disk drives. However, when the disk drives are disposed within the cooling flow path by a large number thereof, because there is a large space above the disk drives, there is a problem that the cooling air of downstream bypasses through the space above the disk drives, in particular, in the zigzag arrangement where the flow resistance is large; i.e., there is no problem of equalizing the temperature distribution among the disk drives.  
         [0018]     With the conventional technology described in the Patent Document 4, although an improvement can be obtained on the cooling performances of the disk drive by itself, however there is no disclosure of the structures for cooling a group of the disk drives as a whole, in particular, when a plural number of disk drives are disposed in the downstream side; i.e., there is no problem of equalizing the temperature distribution among the disk drives.  
         [0019]     Also, with those conventional technologies relating to the Patent Document 1 to the Patent Document 4, there is disclosed the structures for reducing the noises generated within the disk array apparatus.  
       BRIEF SUMMARY OF THE INVENTION  
       [0020]     An object according to the present invention is to provide a disk array apparatus obtaining an equalization of cooling among the disk drives, as well as, reduction of noises within the apparatus thereof.  
         [0021]     For accomplishing the object mentioned above, according to the present invention, there is provided a disk array apparatus, comprising: disk drives, which are mounted on a plural number of lines, in a direction of proceeding of an air flow; a housing containing said disk drives therein; and flow passages provided between an upper surface of said disk drives and an inner wall of an upper surface of said housing, for allowing said air flow to pass through, wherein a dam is provided for narrowing said air flow, above said disk drives, in a downstream side of said flow passages.  
         [0022]     And, the above object mentioned above is accomplished by the disk array apparatus, as described in the above, wherein said dam is made of a sound absorbing material and said dam is attached on the inner wall of the upper surface of said housing.  
         [0023]     Also, for accomplishing the object mentioned above, according to the present invention, there is further provided a disk array apparatus, comprising: disk drives, which are mounted on a plural number of lines, in a direction of proceeding of an air flow; a housing containing said disk drives therein; and flow passages provided between an upper surface of said disk drives and an inner wall of an upper surface of said housing, for allowing said air flow to pass through, wherein a shield plate is provided for shielding a direction of the air flow passing through said disk drives, in a downstream side of said flow passages, and on said shielding plate are provided openings corresponding to shapes of said disk drives.  
         [0024]     And, the above object mentioned above is accomplished by the disk array apparatus, as described in the above, wherein said shield plate is so disposed that spaces are opened alternately in a direction of height in a front and a rear of said disk drives.  
         [0025]     Also, the above object mentioned above is accomplished, by the disk array apparatus, as described in the above, wherein a heat sink is attached on one of sidewalls of each of said disk drives.  
         [0026]     And, also the above object mentioned above is accomplished, by the disk array apparatus, as described in the above, wherein a dummy is attached at a position where said disk drive is not installed.  
         [0027]     Thus, according to the present invention, it is possible to provide a disk array apparatus obtaining an equal cooling of the disk drives, as well as, silence of the disk drives and/or an apparatus. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0028]     Those and other objects, features and advantages of the present invention will become more readily apparent from the following detailed description when taken in conjunction with the accompanying drawings wherein:  
         [0029]      FIG. 1  is a cross-section view for showing the structures of the disk array apparatus, according to a first embodiment of the present invention;  
         [0030]      FIG. 2  is a brief structural view for showing a backboard in the first embodiment of the present invention;  
         [0031]     FIGS.  3 ( a ) and  3 ( b ) are enlarged partial views for showing the disk array apparatus, according to the first embodiment of the present invention;  
         [0032]     FIGS.  4 ( a ) and  4 ( b ) are enlarged partial views for showing the disk array apparatus, according to a second embodiment of the present invention;  
         [0033]     FIGS.  5 ( a ) and  5 ( b ) are enlarged partial views for showing the disk array apparatus, according to a third embodiment of the present invention;  
         [0034]     FIGS.  6 ( a ) and  6 ( b ) are views for showing the detailed structures of a throttle in flow passage, according to the third embodiment of the present invention;  
         [0035]     FIGS.  7 ( a ) and  7 ( b ) are enlarged partial views for showing the disk array apparatus, according to a fourth embodiment of the present invention;  
         [0036]      FIG. 8  is a view for showing the detailed structures of a throttle in flow passage, according to the fourth embodiment of the present invention;  
         [0037]     FIGS.  9 ( a ) and  9 ( b ) are enlarged partial views for showing the disk array apparatus, according to a fifth embodiment of the present invention;  
         [0038]     FIGS.  10 ( a ) and  10 ( b ) are enlarged partial views for showing the disk array apparatus, according to a sixth embodiment of the present invention;  
         [0039]      FIG. 11  is a view for showing the detailed structures of a disk drive, according to the sixth embodiment of the present invention;  
         [0040]      FIG. 12  is a the cross-section view for showing the structures of a disk drive, according to a seventh embodiment of the present invention;  
         [0041]      FIG. 13  shows a graph for showing effects of the present invention;  
         [0042]      FIG. 14  is a perspective view for showing the disk array apparatus, according to the present invention;  
         [0043]      FIG. 15  is a perspective view for showing a system of the disk array apparatus, according to the present invention; and  
         [0044]      FIG. 16  is also a perspective view for showing a system of the disk array apparatus, according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0045]     Hereinafter, embodiments according to the present invention will be fully explained by referring to the attached drawings.  
         [0046]     Explanation will be given about a first embodiment according to the present invention, by referring to FIGS.  1  to  3 ( b ).  
       EMBODIMENT 1  
       [0047]      FIG. 1  is a cross-section view of the disk array apparatus, according to the present embodiment.  
         [0048]      FIG. 2  is a brief structural view of a backboard, according to the present invention.  
         [0049]      FIG. 3 ( a ) is a partial sides view of the disk array apparatus, according to the present invention, and  FIG. 3 ( b ) is an upper view of  FIG. 3 ( a ).  
         [0050]      FIG. 14  is a perspective view of the disk array apparatus, according to the present invention.  
         [0051]     In the figures, within a housing  1  of the disk array apparatus, a portion of installing a large number of disk drives  2  is disposed in a front, while an electric power source  6  and a controller circuit board  7  are installed in a rear portion thereof. Also, at the end there of is provided a fan unit  8 . The disk drives  2  are connected onto a motherboard  4  through connectors  3 . The motherboard  4  is connected to a backboard  5  with an aid of wiring (not shown in the figure). Also, the electric power source  6  and the controller circuit board  7  are connected onto the backboard  5  through connectors  3 ′. On the backboard  5  are provided airflow orifices  9 , as is shown in  FIG. 2 . Those airflow orifices  9  are provides so that a numerical aperture comes to be almost equal or uniform to all over an area of the backboard.  
         [0052]     However, in the present embodiment, among the connectors  3  on the motherboard  4 , a dummy (disk drive) is mounted in a portion, on which no disk drive  2  is mounted. The dummy is adjusted so as to have the flow resistance same to that of the disk drive  2 , and it is a box having the outer sizes thereof, for example, which is same to that of disk drive  2 . This is also same to other embodiments.  
         [0053]     In the present embodiment, maintenance of the disk drive  2  is made by opening a cover, which is provided in a front upper portion of the housing  1 , after drawing out the housing  1  from a container portion thereof. In case where a large number of disk drives  2  are installed, like in the present case, there is necessity of a room in the sense of space, for allowing the disk drives  2  to be inserted/drawn out upwards.  
         [0054]     In the present embodiment, above the disk drives  2  on the downstream side is provided a throttle  10  of flow path (i.e., a dam). This flow path throttle  10  has the structure combining a sound absorbing material in common.  
         [0055]     In such structures, cooling wind driven by the fan unit  8  flows into from a front of the housing  1 , and after cooling the respective disk drives  2 , it passes through the backboard  5 . Further, after cooling the electric power source  6  and the control board  7 , it is discharged from a rear side of the housing  1 . However, because the numerical aperture is almost equal about the airflow orifices  9 , which are provided in the backboard  5 , flow velocity of the flow through the disk drives  2  comes to be nearly constant in the cress-section of the flow passage. In this instance, since being heated by the heat-generation body, which is disposed on the way thereof, the cooling wind raises up temperature thereof, as it comes down to downstream. For this reason, the temperature of the disk drives  2  in the downstream side increases, comparing to that of the disk drives in the upstream side. However, in the present embodiment, due to the function of the flow path throttle  10 , which is provided upwards the disk drives  2  in the downstream side, the flow passage is reduced or narrowed, then the cooling wind, being cut off from escape, flows into the side of the disk drives  2 , and it hits on the disk drives  2  with increasing wind velocity thereof; therefore, cooling is preferable, in particular, for the disk drives  2  in the downstream side. With this, it is possible to lessen the unevenness or fluctuation on temperature of the disk drives  2  between the upstream side and the downstream side.  
         [0056]     Also, since the numerical aperture of the airflow orifices  9 , which are provided in the backboard  5  by a large number thereof, is almost equal to the cross-section of flow passage, and dummies are mounted on the portion where the disk drives  2  are not mounted, therefore the flow velocity through the disk drives  2  is nearly constant on the cross-section of flowpassage; i.e., it is possible to lessen the unevenness in temperature on the disk drives  2 , in particular, in the direction of the cross-section of flow passage.  
         [0057]     According to the present embodiment, it is possible to bring the respective disk drives  2  into preferable conditions thereof while aligning the disk drives  2 , as they are, ordinarily.  
         [0058]     According to the present embodiment, since cooling can be made effectively by means of the fan unit  8  having a small capacity thereof, it is possible to reduce the noises coming out from the fan. Also, the flow path throttle  10  has the structures combining the sound absorbing material, in common with; therefore it is possible to absorb the noises generated by the respective disk drives  2  with high efficiency.  
       EMBODIMENT 2  
       [0059]     FIGS.  4 ( a ) and  4 ( b ) are views for showing a second embodiment, in the similar manner to FIGS.  3 ( a ) and  3 ( b ).  
         [0060]     In those FIGS.  4 ( a ) and  4 ( b ) are arranged the disk drives  2  also in the zigzag manner, and with this, though increasing the flow resistance thereof, however mixture of cooling airs can be accelerated among the disk drives  2 ; therefore, further preferable cooling performances can be obtained.  
         [0061]     Further, there is also provided the flow path throttle  10 , being made up with the material having sound absorbing characteristics above of the disk drives  2  in the downstream side. With this, it is possible to remove a problem that is caused when disposing the large number of disk drives within the cooling flow passage, i.e., flow of the cooling air on the downstream side bypassing into the upper space of the disk drives. Further, the cooling wind flowing above the disk drives  2 , but not being heated, hits onto the disk drives  2  while increasing the wind velocity thereof; therefore, the cooling obtained in the disk drives  2  on the downstream side are very preferable. With this, it is possible to make the unevenness in the increase of temperature small, in particular, between the disk drives  2  in the upstream and the downstream.  
         [0062]     According to the present embodiment, since effective cooling can be obtain even by the fan unit  8  having small capacity thereof, therefore it is possible to reduce the noises generated from the fan. Also, the flow path throttle  10  has the structures combining the sound absorbing material, in common with; therefore it is possible to absorb the noises generated by the respective disk drives  2  with high efficiency.  
       EMBODIMENT 3  
       [0063]     FIGS.  5 ( a ) and  5 ( b ) and  6 ( a ) and  6 ( b ) are views for showing a third embodiment, and FIGS.  5 ( a ) and  5 ( b ) are similar views of FIGS.  3 ( a ) and  3 ( b ).  
         [0064]     FIGS.  6 ( a ) and  6 ( b ) are views for showing the details of a flow path throttle  10 ′, according to the present embodiment.  
         [0065]     Within the present embodiment, the flow path throttle  10 ′ is made from a plate having a large number of openings  9 ′ therein, and each of the openings  9 ′ are corresponding to the position of the each disk drive  2 , respectively. Namely, it is so designed that the cooling winds come gather into outer periphery portions of the disk drives  2 . In the embodiment shown in FIGS.  5 ( a ) and  5 ( b ), the flow path throttles  10 ′ are provided, in a front and a rear of the disk drives  2 . Further, also in the present embodiment, the flow path throttle  10 ′ is made of a material having the sound absorbing characteristics.  
         [0066]     In such the structures, due to the function of the flow path throttle  10 ′ provided in the front and the rear of the disk drives  2  on the downstream side, the flow passage is reduced or narrowed, locally, and the cooling winds not heated so much, flowing above the disk drives  2  and at a center of the disk drives  2 , hit onto the disk drives  2  with increasing the wind velocity thereof, and therefore, preferable cooling can be obtained at portions, in particular, at a front edge and a rear edge portions, on the disk drives  2  on the downstream side. With this, it is possible to lessen the unevenness or fluctuation on temperature of the disk drives  2  between the upstream side and the downstream side.  
         [0067]     Also, the numerical aperture of the large number of openings  9 ′, which are provided on the flow path throttle  10 ′, is equal to the cross-section of the flow passage, and dummies are mounted on the portion where the disk drives  2  are not mounted, therefore the flow velocity through the disk drives  2  is nearly constant on the cross-section of flow passage, completely; i.e., it is possible to lessen the unevenness in temperature on the disk drives  2  in the direction of the cross-section of flow passage.  
         [0068]     According to the present embodiment, it is possible to bring the respective disk drives  2  into preferable conditions thereof while aligning the disk drives  2 , as they are, ordinarily.  
         [0069]     According to the present embodiment, since cooling can be made effectively by means of the fan unit  8  having a small capacity thereof, it is possible to reduce the noises coming out from the fan. Also, the flow path throttle  10 ′ has the structures combining the sound absorbing material, in common with; therefore, it is possible to absorb the noises generated from the respective disk drives  2 , with high efficiency.  
       EMBODIMENT 4  
       [0070]     FIGS.  7 ( a ) and  7 ( b ) and  FIG. 8  are views for showing a fourth embodiment, and FIGS.  7 ( a ) and  7 ( b ) are enlarged partial views of the disk array apparatus, according to the present embodiment.  
         [0071]      FIG. 8  is a view for showing the detailed structure of a flow path throttle  10 ″ according to the present embodiment.  
         [0072]     In FIGS.  7 ( a ) and  7 ( b ) and  FIG. 8 , the flow path throttle  10 ″ is made from a plate having a large number of projections  11  on a lower side thereof, and the positions of those projections  11  are corresponding to a central position between the disk drives  2 , respectively. Within the embodiment shown in FIGS.  7 ( a ) and  7 ( b ), the projections  11  are provided at the positions of the disk drives  2  on the most downstream side. Namely, it is so designed that the cooling winds come gather around the disk drives  2  on the most downstream side, in particular. Further, also in the present embodiment, the flowpath throttle  10 ″ is made of a material having the sound absorbing characteristics.  
         [0073]     In the present embodiment, due to the faction of the flow path throttle  10 ″, which are provided above the disk drives  2  on the downstream side, the flow passage is reduced or narrowed for the disk drives  2  on the third line and thereafter, the cooling wind not heated, flowing above the disk drives  2  hits onto the disk drives  2  with increasing the wind velocity thereof; therefore, preferable cooling can be obtained on the disk drives in the down streamside. Further, with the disk drives  2  on the fourth line, the cooling wind flows around the disk drives  2 , being further accelerated by means of the projection  11 , and therefore the cooling obtained on the disk drives  2  comes to be very preferable.  
         [0074]     With this, it is possible to make the unevenness in the increase of temperature small, in particular, between the disk drives  2  in the upstream and the downstream.  
         [0075]     Also, due to the functions of the projections  11 , which are provided on the flow path throttle  10 ″, since the flow resistance is controlled when the cooling wind flows through the flow passage, it is possible to lessen the unevenness in temperature on the disk drives  2 , in particular, in the direction of the cross-section of flow passage.  
         [0076]     According to the present embodiment, it is possible to bring the respective disk drives  2  into preferable conditions thereof while aligning the disk drives  2 , as they are, ordinarily.  
         [0077]     According to the present embodiment, since cooling can be made effectively by means of the fan unit  8  having a small capacity thereof, it is possible to reduce the noises coming out from the fan. Also, the flow path throttle  10 ″ has the structures combining the sound absorbing material, in common with; therefore, it is possible to absorb the noises generated from the respective disk drives  2 , with high efficiency.  
       EMBODIMENT 5  
       [0078]     FIGS.  9 ( a ) and  9 ( b ) are views for showing a fifth embodiment, and are enlarged partial views of the disk array apparatus, according to the present embodiment.  
         [0079]     Flowpath throttles  10 ″′, according to the present embodiment, each being made from a plate having on opening portion therein, are located in a front and a rear of two (2) lines of disk drives in the downstream side, so that a space can be opened in the direction of height. Also, in the present embodiment, the flow path throttles  10 ″ 40  are made of a material having the sound absorbing characteristics.  
         [0080]     In such the structures, due to the functions of the flow path throttles  10 ″′, which are provided in the front and the rear of the disk drives in the downstream side, the cooling wind flowing above the disk drives  2  and in the center between the disk drives  2 , hits onto the disk drives  2  while flowing in a zigzag manner into up and down directions and also increasing the wind velocity thereof; therefore, preferable cooling can be obtained on the disk drives  2  in the downstream side. With this, it is possible to make the unevenness in the increase of temperature small, in particular, between the disk drives  2  in the upstream and the downstream.  
         [0081]     According to the present embodiment, it is possible to bring the respective disk drives  2  into preferable conditions thereof while aligning the disk drives  2 , as they are, ordinarily.  
         [0082]     According to the present embodiment, since cooling can be made effectively by means of the fan unit  8  having a small capacity thereof, it is possible to reduce the noises coming out from the fan. Also, the flow path throttle  10 ″′ has the structures combining the sound absorbing material, in common with; therefore, it is possible to absorb the noises generated from the respective disk drives  2 , with high efficiency.  
       EMBODIMENT 6  
       [0083]     FIGS.  10 ( a ) and  10 ( b ), and  FIG. 11  are views for showing a sixth embodiment, and FIGS.  10 ( a ) and  10 ( b ) are enlarged partial views of the disk array apparatus, according to the present embodiment.  
         [0084]      FIG. 11  is a view for showing the detailed structures of a disk drive having a heat sink, according to the present embodiment.  
         [0085]     In those FIGS.  10 ( a ) and  10 ( b ), and  FIG. 11 , a heat sink  12  is attached on one of sidewalls of the disk drive  2 . In the present embodiment, though there is only shown the heat sink  12  of a shape, having a large number of plates aligned, however the heat sink should not be restricted to this, in the shape thereof, and it may be in any kind of shapes, as far as it can increase an area for heat radiation.  
         [0086]     Also, in the present embodiment, above the disk drives  2  in the downstream side, there is provided the flow path throttle  10 , which is made of a material having the sound absorbing characteristics, in the similar manner to the first embodiment.  
         [0087]     In such the structures, due to the functions of the heat sink  12 , very preferable cooling of the respective disk drives  2  can be achieved. Further, due to the functions of the flow path throttle  10 , which is provided above the disk drives in the downstream side, the flow passage is reduced or narrowed, and therefore the cooling wind not heated, flowing above the disk drives  2 , hits onto the disk drives  2  with increasing the wind velocity thereof; therefore, further preferable cooling can be obtained on the disk drives  2  in the downstream side. With this, it is possible to make the unevenness in the increase of temperature small, in particular, between the disk drives  2  in the upstream and the downstream.  
         [0088]     Further, if it is so designed that the number of pieces of fins of the heat sink is much more, for the disk drives  2  in the downstream side, it is further possible to reduce the unevenness in the increase of temperature, in particular, between the disk drives  2  in the upstream side and the downstream side, much more.  
         [0089]     According to the present embodiment, since cooling can be made effectively by means of the fan unit  8  having a small capacity thereof, it is possible to reduce the noises coming out from the fan. Also, the flow path throttle  10  has the structures combining the sound absorbing material, in common with; therefore, it is possible to absorb the noises generated from the respective disk drives  2 , with high efficiency.  
       EMBODIMENT 7  
       [0090]      FIG. 12  is a view for showing a seventh embodiment, and is a cross-section view of the structures of the disk array apparatus, according to the present embodiment. In this  FIG. 12 , above all the disk drives  2  are provided the flow path throttles  10 , which are made of a material having the sound absorbing characteristics.  
         [0091]     With such the structures, no cooling air bypasses above the disk drives  2 , preferable cooling can be obtained for the respective disk drives  2 . Also, cooling can be made effectively by means of the fan unit  8  having a small capacity thereof; therefore, it is possible to reduce the noises coming out from the fan. Further, the flow path throttle  10  has the structures combining the sound absorbing material, in common with; therefore, it is possible to absorb the noises generated from the respective disk drives  2 , with high efficiency.  
         [0092]      FIG. 13  is a graph for showing an example of effects, which can be obtained, according to the present invention.  
         [0093]     In this  FIG. 13 , first of all, explanation will be made about the operations of the disk drives  2 .  
         [0094]     Upon receipt of a command transmitted from the controller, the disk drives  2  is turned into any one of “Ready”, “Not Ready” and “Power OFF” in the operation condition thereof. Among of those, the disk drives  2  operating under the “Ready” condition are able to receive a command of reading/writing data, which is transmitted from the controller. The disk drives  2  operating under the “Ready” condition are rotating at the rotation speed necessary for conducting the reading/writing of data.  FIG. 13  shows the maximum values of an increase of temperature on the disk drives  2 , under an idling condition where no data is read/written under the “Ready” condition. For the disk array apparatus, it is general to take the maximum value of the increase in temperature to be about 15° C. With the conventional art, it comes up to about 15° C. under the idling condition, and therefore cooling cannot be conducted upon the disk drive  2  under the condition of reading/writing of data. According to the present invention, there can be obtained a room in the temperature, then cooling can be conducted upon the disk drives  2  under the condition of reading/writing data thereon. For example, under the condition of the embodiment 3, cooling can be obtained, fully, even when all the disk drives  2  are operating on a load equal or greater than 50% of the maximum load thereof. By the way, if the disk drives increase the number thereof, there is no chance that all the disk drives  2  are operated under the maximum load condition thereof.  
         [0095]     Thus, in case of the disk array apparatus according to the present invention, it is possible to improve the cooling performances of the disk drives, and to suppress the unevenness of temperature, and in its turn to obtain an improved reliability and a long lifetime of the disk drives, as well as, enabling an installation of disk drives at high density, and obtaining a large capacity and high speed of the disk array apparatus. And, it is also possible to provide a disk array apparatus of low noises.  
       EMBODIMENT 8  
       [0096]     An eighth embodiment according to the present invention is shown in  FIGS. 15 and 16 . Those  FIGS. 15 and 16  show a system of the disk array apparatus, according to the present embodiment.  
         [0097]     In the present embodiment, the housings  1  of the disk array apparatuses, which are described in the embodiments 1 to 7, are installed within an inside of a system housing  100 , in the vertical direction, by a large number thereof.  
         [0098]      FIG. 15  shows an example of applying a standard rack as the system housing  100 , in which the housings in the large number thereof  1  are installed in the direction of height thereof. With such the structures, since cooling can be made effectively by means of the fan unit  8  having a small capacity thereof, it is possible to reduce the noises coming out from the fan.  
         [0099]     In the embodiment shown in  FIG. 16 , the housings  1  are installed on the front and the rear surfaces (in other words, in the direction of both sides) of the system housing, into the vertical direction thereof, by a large number thereof. Also, within the system housing  100  are provided a system fan unit  101 , and a system electric power source  102 . With such the structures, since cooling can be made effectively by means of the fan unit  8  having a small capacity thereof, it is possible to reduce the noises coming out from the fan, as well as, heats discharged from the respective housings  1  can be discharged into an outside of the system housing  100 , smoothly, due to the functions of the system fan units  101 .  
         [0100]     The present invention may be embodied in other specific forms without departing from the spirit or essential feature or characteristics thereof. The present embodiment(s) is/are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the forgoing description and range of equivalency of the claims are therefore to be embraces therein.