Control device, control method, and control program

Provision of a control device, method and program capable of performing a suitable temperature control in a room having an equipment installed therein. A control device controls air-conditioning of a room having installed therein a plurality of pieces of equipment each being capable of drawing outside air to thereby cool down an interior of the equipment. A storage portion is capable of storing therein operating information that represents as to whether it is abnormal or not if each piece of equipment is put into a non-operating state. A temperature measurement portion is capable of measuring a temperature of the air drawn by each piece of equipment. A detection portion is capable of measuring a flow speed of the air drawn by each piece of equipment. A control portion is configured to control the air-conditioning based on the measurement result of the temperature or the flow speed of the air drawn by each piece of equipment.

FIELD OF THE INVENTION

The present invention generally relates to a control device, a control method, and a control program. More particularly, the present invention relates to a control device, a control method, and a control program capable of controlling air-conditioning of a room having equipment installed therein.

BACKGROUND OF THE INVENTION

A server room of a data center has installed therein a number of server units, generating a large amount of heat. Therefore, it is necessary to efficiently control air-conditioning of the server room of the data center to control the temperature.

In the past, in a server room, an air-conditioning control wherein a temperature of a cool air supply (or blowing out) port of an air-conditioning unit is controlled to be constant, an air-conditioning control wherein a temperature of a warm air return port of the air-conditioning unit is controlled to be constant, or an air-conditioning control wherein a temperature of a wall surface of the server room is controlled to be constant has been performed, for example. Moreover, in some cases, a combination of such air-conditioning controls has been performed.

The server unit is configured to draw outside air through an intake port by means of a fan to thereby cool down an interior of the server room. Therefore, in some cases, an air-conditioning control wherein a temperature of air drawn into the interior of the server unit through the intake port is controlled to be constant has been performed.

As an operating method of a server system having a number of server units, there is known a method wherein some server units are put into a non-operating state during a period where a system load is low. By using such an operating method, it was possible to suppress the power consumption and resultant generated heat of the server system.

FIG. 1is a diagram illustrating an example of a plurality of server units mounted in a rack with the flow of indrawn air and exhaust air around the rack. When air-conditioning is used to control and maintain a constant temperature of the air drawn through the intake port of each of the server units, the following problems may occur if some server units are put into a non-operating state.

In the server unit in the non-operating state, the rotation of an internal fan thereof is stopped. Therefore, when a non-operating server unit is present among a plurality of operating server units, warm air exhausted from other server units may flow back to an intake port through an exhaust port of the non-operating server unit. As a result, the temperature detected by a temperature sensor mounted in the vicinity of the intake port of the non-operating server unit may exhibit (or indicate) a high value compared with the temperature of cool air supplied from an air-conditioning unit. Therefore, a control device for controlling the air-conditioning within the server room may perform control so that the temperature within the server room becomes lower than a present temperature. Accordingly, it is impossible to perform a suitable temperature control.

Japanese Patent Application Laid-Open No. 2006-208000 discloses a device provided with airflow sensors coupled to a plurality of fans in a server in a data center and a controller for controlling cooling of the data center in accordance with the detected airflow. In addition, Japanese Patent Application Laid-Open No. 2006-208000 describes that a three-dimensional airflow map is generated based on the detected airflow and the fan location. However, according to the invention disclosed in Japanese Patent Application Laid-Open No. 2006-208000, it may be difficult to perform a suitable temperature control when a non-operating server unit is present.

Japanese Patent Application Laid-Open No. 9-298377 discloses a device provided with a temperature sensor for measuring a temperature of air discharged through a ventilation port of a heat exchanger and a flow speed sensor for measuring a flow speed of air discharged through the ventilation port of the heat exchanger. According to the invention disclosed in Japanese Patent Application Laid-Open No. 9-298377, although it is possible to detect a failure of the heat exchanger, it may be difficult to perform a suitable temperature control when a non-operating server unit is present.

Japanese Patent Application Laid-Open No. 2002-032152 discloses a method for automatically interrupting the supply or the cutoff of electric power to an information system based on a comparison between a flow speed measurement of cooling air flowing into the information system and a reference value. According to the invention disclosed in Japanese Patent Application Laid-Open No. 2002-032152, although it is able to detect an abnormality in the flow speed due to a failure or the like of an internal fan and to perform a shutdown process, it may be difficult to perform a suitable temperature control when a non-operating server unit is present.

SUMMARY OF THE INVENTION

The present invention provides a control device, a control method, and a control program, capable of solving or obviating these and other deficiencies of the prior art.

In accordance with an aspect of the present invention, there is provided a control device for controlling air-conditioning of a room containing equipment capable of drawing outside air to cool down an interior of the equipment, comprising: a temperature measurement portion for measuring a temperature of air drawn by the equipment; a detection portion for detecting whether the equipment is drawing or exhausting air; and a control portion for controlling the air-conditioning based on the measured temperature and whether the equipment is drawing or exhausting air.

In accordance with another aspect of the present invention, there is provided a control device for controlling air-conditioning of a room containing equipment, the equipment being capable of drawing outside air to cool down an interior of the equipment, comprising: a storage portion for storing operating information representing whether it is abnormal if the equipment is placed in a non-operating state, or if it is not abnormal even when the equipment is placed in the non-operating state; a temperature measurement portion for measuring a temperature of air drawn by the equipment; a detection portion for measuring a flow speed of air drawn by the equipment; a holding portion for holding the temperature measurement portion and the detection portion; a driving portion for moving the holding portion toward an intake port side of the equipment; and a control portion for controlling the driving portion to measure the temperature or the flow speed of air drawn by the equipment to control the air-conditioning based on a measurement result, the control portion being configured to: determine that the equipment is drawing air by comparing the measured flow speed to a reference value; control the air-conditioning to decrease the temperature of air drawn by the equipment when the measured temperature is higher than a reference temperature, and the equipment is drawing air at a flow speed of at least the reference value; output a warning to a user when the operating information indicates that it is abnormal if the equipment is placed into a non-operating state, and the equipment is not drawing air at a flow speed of at least the reference value; and maintain a control state of the air-conditioning when the operating information indicates that it is not abnormal if the equipment is placed into a non-operating state and is not drawing air.

In accordance with another aspect of the present invention, there is provided a control method for controlling air-conditioning of a room containing equipment capable of drawing outside air to cool down an interior of the equipment, comprising: measuring a temperature of air drawn by the equipment; detecting whether the equipment is drawing or exhausting air; and controlling the air-conditioning based on the measured temperature and whether the equipment is drawing or exhausting air.

In accordance with another aspect of the present invention, there is provided a computer program stored on a computer readable medium, which when executed by a computer, controls air-conditioning of a room containing equipment capable of drawing outside air to cool down an interior of the equipment, comprising program code for: measuring a temperature of air drawn by the equipment; detecting whether the equipment is drawing or exhausting air; and controlling the air-conditioning based on the measured temperature and whether the equipment is drawing or exhausting air.

In the summary of the present invention, not all the necessary features of the invention are listed. Sub-combinations and other combinations of the features can constitute the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described with respect to an embodiment thereof. The embodiment described below, however, is not limiting of the invention set forth in the appended claims, and all combinations of features described in the description of the embodiment are not necessarily indispensable to the solution according to the present invention.

FIG. 2is a diagram illustrating an exemplary construction of a data center10according to an embodiment of the present invention.FIG. 3is a diagram illustrating an example of a plurality of pieces of equipment, in this case server units30, mounted in a rack20and the flow of air around the rack20.

The data center10is provided with a server room12, an air-conditioning unit14, and an air-conditioning control portion16. In the server room12, at least one rack20is provided. The air-conditioning unit14adjusts the air-conditioning of the interior of the server room12. That is, the air-conditioning unit14supplies cool air to the interior of the server room12and receives warm air from the interior of the server room12, so that a temperature of the interior of the server room12is adjusted to become equal to a predetermined temperature setting value.

The air-conditioning control portion16is configured to control an operation of the air-conditioning unit14to control the air-conditioning of the interior of the server room12. By way of an example, the air-conditioning control portion16may be configured as a computer that executes a program.

The rack20is configured to mount therein at least one server unit30. Each of the server units30is connected to a network and is capable of performing data computation processing and data storage.

Each server unit30includes a mechanism for drawing in outside air to cool down an interior of the server unit30during an operating state. In an embodiment, each server unit30is provided with an internal fan, which is configured to rotate so that the outside air is drawn through an intake port to cool down the interior while exhausting warm air through an exhaust port. Moreover, in an embodiment, each server unit30is configured to stop the rotation of the internal fan during a non-operating state.

In the present embodiment, at least one of the server units30mounted in each rack20is arranged such that outside air is drawn from mutually identical directions while inside air is exhausted from mutually identical directions. More specifically, at least one of the server units30is arranged such that an intake port is oriented toward a first side surface (hereinafter, referred to as “intake-side side surface22”) of the rack20, and an exhaust port is oriented toward a second side surface (hereinafter, referred to as “exhaust-side side surface24”) opposite the intake-side side surface22of the rack20. Moreover, a plurality of racks20of the server room12are arranged within the server room12so that the intake-side side surfaces22of neighboring racks20face each other, and the exhaust-side side surfaces24of the neighboring racks20face each other.

Furthermore, in an present embodiment, the air-conditioning unit14is configured to supply cool air to the interior of the server room12through a floor side of the server room12and receive warm air from the interior of the server room12through a ceiling side of the server room12. The air-conditioning unit14may be configured to supply cool air, through ventilation ports26provided to a floor thereof, to a space surrounded by the intake-side side surfaces22of two neighboring racks20. By way of an example, the air-conditioning unit14may be one which is capable of adjusting a temperature or the like of cool air for each of the ventilation ports26.

In addition, the data center10is provided with at least one temperature measurement portion42and at least one detection portion44. The respective temperature measurement portions42and detection portions44are provided so as to correspond to at least one of the server units30provided in the server room12.

FIG. 4is a block diagram illustrating an exemplary functional construction of a control device50according to an embodiment of the present invention. In the data center10illustrated inFIGS. 2 and 3, in the air-conditioning control portion16, at least one of the temperature measurement portion42and at least one of the detection portion44cooperate with each other to function as the control device50that controls air-conditioning of the server room12in which the server units30are installed. That is, the control device50is provided with at least one temperature measurement portion42, at least one detection portion44, and the air-conditioning control portion16, and is configured to control the air-conditioning unit14so that the interior of the server room12can be maintained at a suitable temperature, humidity, and the like. Moreover, the control device50according to the present embodiment may be configured to control the air-conditioning of a room having installed therein other equipment capable of drawing outside air to thereby cool down an interior thereof, without being limited to the server room12in which the server unit30is installed.

Each of the temperature measurement portions42is provided at an intake port side of a corresponding server unit30so as to measure a temperature of the air drawn into the server unit30. Each of the temperature measurement portions42may be provided at a position of the intake-side side surface22of the rack20disposed close to the intake port of the corresponding server unit30. Each of the temperature measurement portions42may be configured to send or deliver a measurement result to the air-conditioning control portion16via a wired or wireless transmission system.

Each of the detection portions44is capable of detecting whether each of the server units30is drawing or exhausting air. Owing to this configuration, each of the detection portions44is capable of detecting whether each of the server units30is in an operating state or a non-operating state. Each of the detection portions44may be configured to deliver a detection result to the air-conditioning control portion16via a wired or wireless transmission system.

Each of the detection portions44may be provided at an intake port side of a measurement target server unit30. That is, each of the detection portions44may be provided at a position of the intake-side side surface22of the rack20disposed in the vicinity of (close to) the intake port of the measurement target server unit30. Moreover, each of the detection portions44may be configured as an anemometer for measuring a flow speed of the drawn air.

Alternatively, each of the detection portions44may be provided at an exhaust port side of the measurement target server unit30. That is, each of the detection portions44may be provided at a position of the exhaust-side side surface24of the rack20disposed in the vicinity of the exhaust port of the measurement target server unit30. Moreover, each of the detection portions44may be configured as an anemometer for measuring a flow speed of the exhausted air.

The air-conditioning control portion16is provided with a storage portion46and a control portion48. The storage portion46is configured to store therein operating information that represents whether it is abnormal or not if each of the server units30installed in the server room12is put into a non-operating state. Here, by way of an example, equipment that always operates can be said to be abnormal if it is put into a non-operating state. As another example, equipment that continuously operates without stopping during a specified period can be said to be abnormal if it is put into a non-operating state (e.g., during the specified period).

The control portion48is configured to control the air-conditioning unit14based on a measurement result and a detection result of each temperature measurement portion42and each detection portion44, respectively. Here, the control portion48control the air-conditioning based on the temperature measured by the temperature measurement portion42, on condition that the detection portion44has detected that the server unit30is drawing or exhausting air. By way of an example, the control portion48may be configured to determine that the server unit30is drawing or exhausting air when the flow speed is equal to or higher than a reference value.

Moreover, the control portion48may be configured to output a warning to a user when operating information, indicating that it is abnormal if the measurement target server unit30is put into a non-operating state, is stored in the storage portion46(e.g., on condition that the server unit30is neither drawing nor exhausting the air). For example, the control portion48displays warning information on a display portion provided on the control portion48or outputs a buzzer sound or an audible warning signal through a speaker.

FIG. 5is a flow chart illustrating an exemplary operation of the control device50according to an embodiment of the present invention. The flow illustrated inFIG. 5illustrates an example where the detection portion44is configured as an anemometer provided at the intake port of a corresponding server unit30.

The control device50executes the following processes of steps S11to S21during an operating state of any one of the server units30installed in the server room12. The control device50repeats the processes of steps S12to S18for each of the plurality of server units30(S11, S20).

First, the temperature measurement portion42measures a temperature of the air drawn by the measurement target server unit30(S12). Subsequently, the detection portion44measures a flow speed of the air drawn by the measurement target server unit30(S13).

The control portion48then compares the flow speed measured by the detection portion44in step S13is to a reference value (S14). When the flow speed measured by the detection portion44is determined to be the reference value or greater (S14: Yes), the control portion48determines that the measurement target server unit30is in an operating state and that the temperature measured by the temperature measurement portion42in step S12for the server unit30is valid (S15).

When the flow speed measured by the detection portion44is determined to be smaller than the reference value (S14: No), the control portion48proceeds to step S16. In this case, the control portion48may be configured to determine that the flow speed measured by the detection portion44is smaller than the reference value, even when an airflow flowing in a reverse direction to the airflow of the air drawn by the measurement target server unit30is detected.

In step S16, the control portion48reads out the operating information stored in the storage portion46to determine whether or not the measurement target server unit30is a type of equipment which can be said to be operating abnormally if it is put into a non-operating state (S16). When the measurement target server unit30is determined not to be a type of equipment which can be said to be operating abnormally if it is put into a non-operating state (S16: No), the control portion48determines that the measurement target server unit30is in a non-operating state. In this case, the temperature measured by the temperature measurement portion42in step S12for the server unit30is not valid (S17).

When the measurement target server unit30is determined to be a type of equipment which can be said to be operating abnormally if it is put into a non-operating state (S16: Yes), the control portion48displays warning information on a display portion provided to the control portion48or outputs a buzzer sound or an audible warning signal through a speaker, for example (S18). Owing to this configuration, the control portion48is able to send a notification to the user to inform the user that the server unit30is in a non-operating state.

Upon completion of either one of the processes of step S15, S17, or S18, the control portion48determines whether or not the process has been completed for all of the plurality of temperature measurement portions42(S20). Upon completion of the processes of steps S12to S18, for all the temperature measurement portions42, the control portion48proceeds to step S21.

In step S21, the control portion48controls the air-conditioning of the server room12based on the temperature information considered as valid. By way of an example, the control portion48controls the air-conditioning for a server unit30which exhibits a flow speed exceeding the reference value and for which temperature information considered as valid has been detected. Moreover, the control portion48may be configured to maintain a present control state of the air-conditioning for a server unit30which has been determined is normal if put into a non-operating state, and for which the temperature information considered as invalid has been detected. Furthermore, when it is difficult to individually control the air-conditioning for each server unit30, the control portion48may control the air-conditioning for the whole server room12or for each of the ventilation ports26on the floor. In addition, when it is difficult to individually control the air-conditioning for each server unit30, and when a high priority is given to a stable operation of the server units30, the control portion48may decrease the overall temperature of the server room12even when a high temperature has been detected in one of the server units30.

For example, in step S21, the control portion48may be configured to control the air-conditioning to thereby decrease the temperature of the air drawn by the measurement target server unit30when the measured temperature is higher than a reference temperature, on condition that the measurement target server unit30is drawing air. Moreover, the control portion48may be configured to maintain a control state of the air-conditioning when the operating information indicating that it is not abnormal if the measurement target server unit30is put into a non-operating state is stored in the storage portion46(S16: No), on condition that the server unit30is not drawing air.

Furthermore, the control portion48may be configured to control the air-conditioning to decrease the temperature of the air drawn by the server unit30when the measured temperature is higher than a first reference temperature, on condition that the server unit30is drawing air, for example. In this case, the control portion48may control the air-conditioning to decrease the temperature of the air drawn by the server unit30when the measured temperature is higher than a second reference temperature higher than the first reference temperature, regardless of whether or not the server unit30is drawing air. Owing to this configuration, when the detected temperature is too high, the control portion48is able to cool down the server unit30, regardless of the flow speed measured by the detection portion44.

In addition, the control portion48may be configured to control the air-conditioning to decrease the temperature of the air drawn by the server unit30when the operating information indicating that it is abnormal if the measurement target server unit30is put into a non-operating state is stored in the storage portion46, on condition that the server unit30is neither drawing nor exhausting the air. That is, when the fan of the server unit30, which can be said that it is abnormal if it is put into a non-operating state, is stopped, the control portion48may decrease the temperature of the server room12from a target temperature so that an operating state of the server unit30can be maintained.

The control device50having the configuration described above controls the air-conditioning of the server room12based on the temperature information measured by the temperature measurement portion42provided so as to correspond to the server unit30in its operating state. That is, when the measurement target server unit30is in a non-operating state, the control device50controls the air-conditioning of the server room12regardless of the temperature information obtained from the temperature measurement portion42having received the exhaust air or the like from other server units30. Owing to this configuration, the control device50is able to control the air-conditioning of the server room12in an efficient manner.

FIG. 6is a block diagram illustrating a control device50according to a modified example of the embodiment of the present invention, shown along with a plurality of server units30. The control device50according to the modified example has substantially the same configuration and function as the control device50according to the present embodiment, described with reference toFIGS. 2 to 5. Therefore, components having substantially the same configuration and function as those of the control device50according to the present embodiment, described with reference toFIGS. 2 to 5will be denoted by the same reference numerals. A redundant description thereof will not be provided in the following description.

The control device50according to the modified example further includes a holding portion90and a driving portion92. The holding portion90is configured to hold therein at least one of the temperature measurement portion42and the detection portion44. The driving portion92is configured to move the holding portion90toward an intake port side of the measurement target server unit30of a plurality of server units30. The driving portion92may be provided to the intake-side side surface22of the rack20so as to move the holding portion90along the server units30within the rack20.

The control portion48may be configured to control the driving portion92to move the holding portion90based on at least one of the measurement results of the temperature measurement portion42and the detection results of the detection portion44. By way of an example, when the temperature of the air drawn by the server unit30is higher than a predetermined value, the control portion48may further measure the temperature of the air drawn by the server unit30and/or increase the period of time, in which the holding portion90is stopped at the server unit30, to be longer than that of other server units30, so that a more accurate temperature can be measured. By way of another example, the control portion48may perform a similar control when the flow speed of the air drawn by the server unit30is lower than a predetermined value. Furthermore, when the holding portion90is moved to a server unit30, which can be said that it is abnormal if it is put into a non-operating state, the control portion48may increase the time for measuring the temperature of the air drawn by the server unit30to be larger than that of other server units30, and/or increase the period of time in which the holding portion90is stopped at the server unit30to be longer than that of other server units30.

Moreover, the control portion48is configured to control the driving portion92to measure the temperature or the flow speed of the air drawn by each of a plurality of server units30to thereby control the air-conditioning based on the measurement results. According to the control device50having such a configuration, the temperature of the air drawn by each of a plurality of server units30can be accurately measured by a small number of temperature measurement portions42and detection portions44. Moreover, it is possible to accurately detect whether or not each of a plurality of server units30is drawing air.

FIG. 7is a diagram illustrating an exemplary hardware construction of a computer1900according to the embodiment of the present invention. The computer1900according to the present embodiment is provided with a CPU peripheral section having a CPU2000, a RAM2020, a graphic controller2075, and a display device2080connected to each other by a host controller2082. The computer1900further includes an input/output section having a communication interface2030, a hard disk drive2040, and a CD-ROM drive2060connected to the host controller2082by an input/output controller2084, and a legacy input/output section having a ROM2010, a flexible disk drive2050, and an input/output chip2070connected to the input/output controller2084.

The host controller2082connects the RAM2020, and the CPU2000and the graphic controller2075, which access the RAM2020at a high transfer rate. The CPU2000operates in accordance with program stored in the ROM2010and the RAM2020, and controls each component. The graphic controller2075acquires image data generated, by the CPU2000and the like, on a frame buffer provided in the RAM2020, and displays the image data on the display device2080. Alternatively, the graphic controller2075may contain therein a frame buffer for storing the image data generated by the CPU2000or the like.

The input/output controller2084connects the host controller2082, the communication interface2030, which is an input/output device of a comparatively high speed, the hard disk drive2040, and the CD-ROM drive2060. The communication interface2030performs communication with other units via a network.

The sensor interface2032is configured to communicate with the temperature measurement portion42and the detection portion44according to the present embodiment. More specifically, the sensor interface2032acquires, through communication, the measurement result of the temperature of the air drawn by the measurement target server unit30from the temperature measurement portion42. Moreover, the sensor interface2032acquires the determination result as to whether the measurement target server unit30is drawing or exhausting the air, from the detection portion44. The sensor interface2032may be configured to acquire the flow speed of the air drawn by the measurement target server unit30or the flow speed of the air exhausted by the measurement target server unit30.

The hard disk drive2040stores program and data used by the CPU2000within the computer1900. The CD-ROM drive2060reads program or data from a CD-ROM2095and provides the read program or data to the hard disk drive2040via the RAM2020.

Moreover, the input/output controller2084is connected to the ROM2010and input/output devices of a comparatively low speed, i.e., the flexible disk drive2050and the input/output chip2070or the like. The ROM2010stores a boot program executed by the computer1900at the startup time, and/or programs or the like dependent on the hardware of the computer1900. The flexible disk drive2050reads a program or data from a flexible disk2090and provides the read program or data to the hard disk drive2040via the RAM2020. The input/output chip2070connects the flexible disk drive2050to the I/O controller2084while connecting various input/output devices, for example, through a parallel port, a serial port, a keyboard port, a mouse port, and the like, to the I/O controller2084.

A program provided to the hard disk drive2040via the RAM2020is provided by a user in a state of being stored on a recording medium (e.g., a computer readable medium), such as the flexible disk2090, the CD-ROM2095, or an IC card. The program is read out from the recording medium, installed in the hard disk drive2040within the computer1900via the RAM2020, and executed in the CPU2000.

A program installed in the computer1900and causing the computer1900to function as the air-conditioning control portion16includes a control module and a storage module. The program or modules are controlled by the CPU2000or the like and cause the CPU2000of the computer1900to function as the control portion48while causing the RAM2020, the hard disk drive2040, or the like of the computer1900to function as the storage portion46.

Information processing routines described in the program are read into the computer1900, so that the computer1900functions as the storage portion46and the control portion48, which are specific means incorporating therein software and hardware resources described above. Moreover, when computation or processing of information in accordance with the purpose of use of the computer1900according to the present embodiment are realized by the specific means, a special-purpose control device50corresponding to the purpose of use can be constructed.

By way of an example, when communication between the computer1900and external devices or the like is carried out, the CPU2000executes a communication program loaded on the RAM2020and instructs the communication interface2030to perform communication processing based on processing procedures described in the communication program. Upon receipt of a control of the CPU2000, the communication interface2030reads transmission data stored in a transmission buffer area or the like provided on a storage device such as the RAM2020, the hard disk drive2040, the flexible disk2090, or the CD-ROM2095to transmit the read transmission data via a network, or writes reception data received via a network on a reception buffer area or the like provided on a storage device. In this manner, the communication interface2030may be configured to transmit/receive data to/from a storage device by a DMA (direct memory access) method. Alternatively, data may be transmitted/received in such a manner that the CPU2000read data from a storage device or the communication interface2030as a transmission source so that the data can be written to the communication interface2030or a storage device as a transmission destination.

Moreover, the CPU2000reads, by DMA transmission or the like, the entire or necessary portion of the files or databases stored in an external storage device, such as the hard disk drive2040, the CD-ROM drive2060(CD-ROM2095), or the flexible disk drive2050(flexible disk2090), into the RAM2020, and performs a variety of processing onto the data on the RAM2020. Furthermore, the CPU2000returns the processed data to the external storage device by DMA transmission or the like. In such processing, since the RAM2020may be considered as one which temporarily stores therein the contents of the external storage device, in the present embodiment, the RAM2020, the external storage device and the like will be referred to as a memory, a storage portion, a storage device or the like. In the present embodiment, a variety of program and a variety of information such as data, table, or database are stored on such a storage device and subjected to information processing. In addition, the CPU2000may store a portion of the contents of the RAM2020on a cache storage device so that reading/writing can be performed on the cache storage device. In such an implementation aspect, since the cache storage device is capable of performing a portion of the functions of the RAM2020, in the present embodiment, the cache storage device will be intended to be included in the scope of the RAM2020, the memory, and/or the storage device, unless they are described in a distinguished manner.

Furthermore, the CPU2000performs a variety of processing including a variety of computation, information processing, conditional determination, information retrieval and replacement, described in the present embodiment, as specified by a program command sequence, on the data read from the RAM2020, and returns the processed data to the RAM2020. For example, when conditional determination is made, the CPU2000compares a variety of variables used in the present embodiment with another variable or an integer to determine whether or not they satisfy a condition such as larger, smaller, not smaller, not larger, or equal, and proceeds to another command sequence when the condition is satisfied (or not satisfied) or invokes a subroutine.

In addition, the CPU2000is capable of retrieving information stored in files or databases within a storage device. For example, when a plurality of entries, in which an attribute value of a first attribute is correlated with an attribute value of a second attribute, is stored in a storage device, the CPU2000can obtain the attribute value of the second attribute correlated with the attribute value of the first attribute satisfying a predetermined condition by retrieving an entry, of which the attribute value of the first attribute matches with a designated condition, from the plurality of entries stored in the storage device and reading the attribute value of the second attribute stored for the retrieved entry.

The program or modules mentioned above may be stored on an external storage medium. As the recording medium, an optical recording medium such as a DVD or a CD, a magneto-optic recording medium such as an MO, a tape medium, a semiconductor memory such as an IC card, or the like can be used as well the flexible disk2090and the CD-ROM2095. Also, a storage device such as a hard disk or a RAM provided in a server system connected to a special-purpose communication network or the Internet may be used as the recording medium to provide the program to the computer1900via a network.

While the present invention has been described with respect to the embodiment thereof, it is not limited to the scope described above with respect to the embodiment. It is, therefore, to be understood that various changes and medications of the above-described embodiment will readily occur to those skilled in the art. It is apparent from the description in the appended claims that other embodiments of the invention provided by making such changes and modifications are also included in the technical scope of the present invention.