JP2009151472A - Task management device and task management method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a termination notice of a canceled task from being erroneously processed when a high-order program receives a termination notice of task processing from a low-order program in a task management device. <P>SOLUTION: A CPU executes an event manager EM and receives predetermined operation or the like to generate an application task AT for a task of the event manager EM to carry out an application, and a driver task DT of a device driver. EM, AT, DT are hierarchically structured in sequential order of high order. EM generates AT, and AT generates DT. When the task is terminated, it responds to the high-order task. A message management task MM is interposed between these generation and response, and the generation and response are carried out through MM, and information on the communication is stored. This information is retrieved, and when there is a task deleted in EM, MM intercepts a response to the high-order task or does not notify this response. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to message exchange between an application task that has been instructed to generate and delete an application task and a driver task.

  Conventionally, an internal CPU (or MPU) executes various programs in order to process various commands instructed to an electronic device or a personal computer. This program has a hierarchical structure in which a caller main routine calls a callee subroutine to execute various functions. An execution unit of CPU processing for executing a program is called a task.

  As a task management method, for example, the configuration of these programs can be a hierarchical structure of an event manager, an application, and a driver. In this case, the event manager manages and executes these application and driver tasks. Here, these tasks are referred to as an application task and a driver task, respectively. The event manager generates an application task (spawn) when it receives a predetermined key operation, for example, an input such as TV channel switching, or when a predetermined state occurs, that is, when a predetermined event occurs. It is. The application task is a task for executing a program stored in the storage device. By executing this, the CPU sends various instructions to the driver task, and performs a series of operations corresponding to the input.

  For example, in the case of a television, in order to perform a series of operations such as receiving a predetermined channel operation, erasing the screen, selecting a channel, displaying a channel OSD (On Screen Display), etc. Instructs the driver to control the device. The driver task is a driver program that controls the device. For example, a display driver, a tuner driver that controls reception of a TV tuner, and a driver that controls peripheral devices.

  A method for managing such a task will be described with reference to the flowchart of FIG. In this flow, time flows downward. This example of the flow shows processing when an operation for instructing the task 2 is performed after the operation for instructing the task 1 and before the task 1 is completed. For example, assuming channel processing, it can be assumed that task 1 is a task that moves to an external input of a television and task 2 moves to channel 8.

  The event manager EM generates task 1 in response to the operation of the remote controller (ST1). Here, for the sake of simplicity, the application task AT instructs the driver task (corresponding to “request 1” in the figure) to be one process (corresponding to “process 1”).

  In the process of executing the application task AT, an operation request 1 is issued to the driver task DT (ST2). In the driver task DT, process 1 (process1) is executed (ST3). In response to the operation of task 2 during execution of ST3, event manager EM deletes task 1 (ST4) and generates task 2 (ST5).

  The application task AT should instruct the driver task DT to erase the task 1, but this instruction is not performed because the driver task DT is already executing the process 1. In response to ST5, request 2 is output to the driver task DT (ST6). In response to this, the driver task DT executes the process 2 (ST7).

  After that, when the process 1 is completed, the driver task DT returns a response to the application task AT (ST8). Upon receiving this response, the application task AT sends an end notification (END) to the event manager EM (ST8). Thereafter, when an instruction for another task is received, if the previous process has not been completed, the task is erased as in ST4 (ST9). Then, a task that receives the instruction is generated (not shown).

Patent Documents 1 and 2 are provided with a message communication unit that transmits and receives a message or message that describes an address or message number, an information transmission source, a transmission destination, etc. in a system that exchanges data between tasks. Is disclosed.
JP-A-2-297633 JP-A-6-95896

  However, conventionally, if the application task AT receives the response of the process 1 while the application task AT requests the process 2 and is not finished as in the example of FIG. 2, the execution of the process 1 is canceled in ST4 ( Therefore, the application task AT may be mistaken for the process 2 being completed.

  As a result, the process 2 may not be executed without returning any response to the event manager EM. For example, if the process 2 is a process that can be executed when the process 2 is directly executed, but the process 2 cannot be executed after passing through the execution of the process 1, the process 1 is not canceled. Execution of process 2 will fail. Since the AT misunderstands that the process 2 has been completed, the AT does not notify the EM at all. If the AT does not mistakenly indicate that the process 2 has ended, it should have been possible to return the process 1 to its original state or notify the user, but this is not possible. As a result, the user's operation may be ignored without receiving any notification from the apparatus. In addition, after that, the AT may receive an answer to the end of the task from the unintended driver task DT, and the AT processing may become unstable.

  Further, in the configurations of Patent Documents 1 and 2, although the exchange of messages between programs is certainly recorded, there is no disclosure about storing a task scheduled to be responded from a lower-level device in the future. In addition, these patent documents do not disclose the processing when a notification of process cancellation is received from the event manager EM.

  For example, in Patent Document 1, an LU management task for centrally managing tasks is provided. However, in this task management method, a message is attached and management is performed so that the message is simply transmitted to and received from the other task. The purpose of the method is not the management of individual mutual tasks, but the task management based on the assumption that there are three or more devices. Therefore, the logical unit number (Logical Unit Number) is assigned to the logical unit (LU). No. ("Online Computer Glossary of Terms" http://www2.nsknet.or.jp/~azuma/menu.htm)) etc. Therefore, this configuration distinguishes logical unit numbers and does not distinguish between tasks. Since tasks cannot be distinguished and the message of the task is transmitted as it is, when the device of Patent Document 1 is applied and the task 1 is canceled, the AT receives a response from the DT for the end of the process 1 In addition, there is a possibility of misunderstanding that the process 2 is completed.

  Therefore, the present invention prevents, in a task management device, that a higher-level program receives a task processing end notification from a lower-level program and erroneously processes a canceled task end notification, and is suitable for this. It is an object to provide an apparatus and a method.

  In order to solve the above problems, the following configuration is provided.

(1) A storage unit for storing upper and lower program groups having a master-slave relationship and an event manager program that calls and executes these programs according to a predetermined event;
A task processing unit that executes the program group, and the task processing unit performs task processing of a lower-level program based on a call or a request that is performed in accordance with execution of the higher-level program, and the lower-level program In the task management device that obtains the completion response of the task by the upper program,
When the task processing unit performs the call, request, or response between the upper and lower programs and the event manager, the task processing unit intervenes between these programs to transmit the call and response delivery. Executing a message storage program for storing communication information including the response name for identifying the response of the lower-order program for each task.
The task processing unit determines whether or not an instruction for canceling a task already being executed by a lower-level program is received from the event manager, and if a response is received from a task receiving the cancellation instruction, Execute a message blocking program that does not notify the program of the response or blocks the response.

In this configuration, the task processing unit executes the message storage program and stores the communication information of the delivery when performing the call, request, or response between the upper and lower programs and between the event managers. . Since this communication information identifies a response, it is possible to identify which lower program task has been executed. As a result, the execution of the message blocking program blocks or blocks the notification of the response to the higher-level program for the task of the lower-level program that has already received a cancellation instruction. Therefore, since no response is received from the task of the lower-level program that has already been instructed to cancel, the higher-level program does not misunderstand that the processing of the other task has been completed. Moreover, it is possible to prevent the possibility that the processing of the higher-level program will be confused due to an unintended response after erroneous recognition.
Note that the master-slave relationship means that the lower-level program performs processing in response to an instruction or request from the higher-level program.

  (2) By executing the message recording program, the task processing unit describes, as the communication information, a list in which the contents of communication information are listed, and a pointer that links a plurality of lists into an array structure. The list is stored in the storage unit.

  In this configuration, the list is stored as a single data set by linking with a pointer to form an array structure. Therefore, when it is determined whether or not the event manager has received an instruction to cancel a task already executed by a lower-level program, it can be easily searched whether this is the case.

  (3) By executing the message recording program, the task processing unit, as the communication information, in addition to the response name, an API (Application Programming Interface) message name describing an instruction to be sent from the upper program to the lower program And a data set including an application ID (identification) for identifying the application.

  In this configuration, since the API message name and application ID are described, the instruction to the lower program can be managed by the message recording program. In addition, when a task end response is returned from a lower-level program task, it can be more easily searched whether an instruction to cancel the task has already been issued.

  This configuration can be applied to the configuration of (2), but the data set of this configuration in this case corresponds to the list of (2).

  (4) When the task processing unit receives an instruction to cancel the task of the higher-level program from the event manager, the task processing unit deletes the list corresponding to the task that has received the cancellation instruction using a message storage program At the same time, the pointers before and after the list are corrected.

  In this configuration, when a task cancellation is received, a list corresponding to the task for which the cancellation instruction has been received is deleted using a message storage program. Therefore, the data area of the list that has become unnecessary can be saved. At this time, since the pointers before and after the list are corrected, the task processing unit can grasp the list as one unit without dividing the list before and after. Further, it is possible to memorize that the task is canceled due to the absence of the task list.

(5) The storage unit stores an application as the upper program and a device driver as the lower program.
The task processing unit may execute the message storage program when calling and responding between the application and the device driver.

(6) a receiving unit that receives a broadcast and outputs a video signal;
A video processing unit for processing the video signal,
The storage unit stores, as a device driver, a reception driver that controls the reception unit and a video processing driver that controls the video processing unit, and a channel switching application that describes a series of channel switching operations as the application. Remember
The task processing unit may generate tasks for the reception driver and the video processing driver when the channel switching application is executed.

  In this configuration, a television configuration is provided and tasks can be managed.

(7) Using a storage unit that stores the upper and lower program groups having a master-slave relationship, and an event manager program, and a task processing unit that executes the program group,
The task processing unit executes an event manager to call and execute these programs according to a predetermined event, and a task generation step,
The task processing unit is a request step for calling or requesting a lower-order program as the higher-order program is executed,
A lower-level program task step for performing task processing of a lower-level program based on a call or request by the request step;
In a task management method for executing a response step of acquiring a response of completion of a task processed in the lower program task step by an upper program,
In the task generating step or the lower program task step or the response step, the task processing unit is interposed between the upper and lower programs and the event manager to transmit the call and response delivery. When,
A message storage step of storing communication information including a response name for identifying the response of the lower-order program for each task, which is communication information for transfer in the transmission step;
The task processing unit determines whether or not an instruction for canceling a task already being executed by a lower-level program is received from the event manager, and if a response is received from a task receiving the cancellation instruction, It is also possible to execute a blocking step of not reporting the response to the program or blocking the response.

  ADVANTAGE OF THE INVENTION According to this invention, when a high-order task receives the notification of the completion | finish of a task process of a call destination in a task management apparatus, it can prevent processing a task completion notification about a task to interrupt being mistaken. .

  A television which is an embodiment of the present invention will be described with reference to the configuration diagram of FIG. The television includes a main processor 1, a receiving unit 41, an image processing unit and display 42, an audio processing unit 43, and an operation unit 9.

  The main processor 1 has a personal computer CPU or microcomputer configuration, and includes a CPU 10, a RAM 11, and a ROM 12. Various programs are recorded in the ROM 12. The RAM 11 is a memory for temporarily storing. The CPU 10 calls various programs from the ROM 12 to the RAM 11 and executes the programs in the RAM 11.

  In the ROM 12, an event manager 13, an application A16, an application B17, an application C18, a reception driver 21, an image control driver 22, an audio driver 23, and a message management program 3 are recorded as programs. These programs have a hierarchical structure. Details will be described later with reference to FIG.

  When the main processor 1 is activated, the CPU 10 calls the event manager 13 in the RAM 11. An interrupt input is input to the CPU 10 according to the operation of the operation unit 9, and the main processor 1 causes the event manager 13 to be executed. As a result, the CPU 10 grasps the content of the operation of the operation unit 9 and calls a necessary application from the ROM 12 to the RAM 11 for execution.

  Note that a unit of processing for executing these programs (event manager 13, applications 16 to 18, drivers 21 to 23) is referred to as a task, and calling the program by the event manager 13 is referred to as task generation. For example, a task for executing an application is hereinafter referred to as an application task, and calling of these programs is referred to as generation of an application task. The task size varies depending on the program. For example, since the upper layer program calls and executes one or more programs in the lower layer, the size of one task is larger than that of the lower layer.

  The receiving unit 41 receives a broadcast signal. This broadcast signal may be digital or analog. The image processing unit and display unit 42 includes an image processing unit that decodes a video signal and adjusts an aspect ratio, and a display unit. The display device includes a driver that outputs video signal data to each dot.

  Next, referring to FIG. 3, the calling of the program in the main processor 1 will be described in more detail. As described above, these programs have a hierarchical structure. The event manager 13 is the highest layer, 16 to 18 are middle layers, and the drivers 21 to 23 are lower layers. The lower layer program is a subroutine or function of the upper layer program. In accordance with the execution of the upper program, the CPU 10 calls the lower layer program to the RAM 11 and executes it (see the broken line arrow in the figure). In addition, when the execution of the lower layer program is completed during the execution of the upper layer program, the upper layer program receives a response of the completion from the lower layer program (see the dotted arrow in the figure).

  Further, the main processor 1 calls the message management program 3 when calling between the applications 16 to 18 and the various drivers 21 to 23 and when responding to the end of the lower-level program. For example, the event manager 13 may activate it. Then, the response of the end of the lower-level program and the calling of these applications and various drivers are performed through the execution of the program 3.

  The program 3 stores, in the RAM 11, response processing information 31 (response message information) describing the content of a message that responds at the time of calling or at the end of the lower-level program. As described above, the program 3 manages the exchange of data between programs. The program 3 also blocks transmission of information that is no longer needed or information that would be confusing if transmitted if the process of the program process is cancelled. Details will be described later with reference to FIG.

  Note that the step of storing the response processing information 31 of the message management program 3 corresponds to the message storage program of the present invention. The program 3 and the response processing information 31 may reside in the RAM 11.

  Application A16, application B17, and application C18 call each driver 21-23 via the program 3, and perform various series of operation | movement. For example, the application A16 is a channel switching application. The application B17 is an initial setting program. The application C18 is a program for controlling sound and volume.

  In order to execute the application A16, screen deletion, physical channel switching, and channel OSD (On Screen Display) display are performed. For this purpose, necessary information is transmitted to the receiving driver 21 that sends an instruction to the device that receives the broadcast signal, the image and video signal, and the image control driver 22 that controls the screen, and these device drivers are activated. The reception driver 21 drives the reception unit 41. The image control driver 22 drives the image processing unit and the display 42 (see solid line arrows).

  In order to execute the application B17, it is necessary to display the OSD, and the image control driver 22 is activated. In order to execute the application C18, a subroutine of the audio driver 23 for processing the audio signal is called. The audio driver 23 drives the audio processing unit 43.

  Next, an example of the data structure of the response processing information 31 generated by the message management program 3 will be described with reference to FIG. The response processing information 31 can be stored in a list format having a data set as shown in FIG. The left side of FIG. 4A is an example of a variable name, and the right side is its contents. As shown in FIG. 4A, the information 31 includes data including an API (Application Programming Interface) message name apiMsg (API Message), a driver response name drvMsg (driver response Message), and an application ID (identification) AP_ID. Is a set.

  AP_ID describes an instruction sent from the upper program to the lower program. Here, although not shown in FIGS. 2 and 3, the API is a library function or the like for facilitating the description of the program. In this embodiment, the API is interposed between the application and the device driver. ing. More precisely, the API only needs to be interposed between the message management task MM and the driver task DT, or between the AT and MM, but when the MM is created in the same programming language as the AT. For the sake of ease, the former is preferable in terms of ease of program creation.

  The driver response name is a code for identifying the response of the driver task for each task. The application ID (identification) is used to identify the application. Thus, since the API message name and application ID are described, the instruction to the lower program can be managed by the message recording program. In addition, when a task completion response is returned from a lower-level program task, it is possible to more easily search whether or not an instruction to cancel the application task has already been issued from the event manager 13.

  The driver response name drvMsg corresponds to the response name of the present invention. Further, apiMsg and drvMsg can be, for example, unsignedlong type data.

  The format of the response processing information 31 will be described with reference to FIG. The response processing information 31 is in a bidirectional list format. In the bidirectional list format, an address (pointer) is described in the list. For example, for the (n + 1) th list, the address where the nth list is stored and the address where the (n + 2) th list is stored are described. Therefore, if this is followed, the information of the list can be acquired in ascending order of n, n + 1, n + 2,. Conversely, the list information can be acquired in descending order of n, n-1, n-2,. When responses are returned from the device drivers 21 to 23 to the message management program 3, the main processor 1 can search for an application ID and an API message name as to which application the response is in order while following these.

  Next, the task flow of the main processor 1 will be described with reference to FIG. Each vertical column represents execution of each task of event manager EM, application task AT, message management task MM, and driver task DT described in the above column. In this flow, time flows downward.

  The relationship between FIGS. 2 and 3 will be described with respect to FIG. 5. The event manager EM is a task for executing the event manager 13. The application task AT is a task for executing any one of the applications 16 to 18. The execution of the drivers 21 to 23 is a driver task DT. In addition, horizontal arrows represent program calls, requests, and responses. In FIG. 5, it is assumed that the application calls a device driver to perform processing. Further, here, for the sake of simplicity, the application task AT instructs the driver task (corresponding to “request AT1” in the drawing) to be one process (for example, “process 1”).

(ST11) The event manager EM issues an instruction to receive the predetermined event to generate the application task AP1 to the message management task MM. For example, this event can be an input of channel switching received from the remote controller of the operation unit 9.
(ST12) MM receives this and generates application task AT1.
(ST13) A request_AT1 is issued to the MM to execute the driver task DT1 with the execution of AT1.
(ST14) The MM sends a request_M1 to the DT. At this time, the fact that the task AT1 is waiting for a response from the DT is stored in the RAM 11.
(ST15) Based on the request_M1, the DT starts executing the process 1 (process1).

  Assume that another event, such as channel switching, has entered from AT1 before the notification of the end of process 1 comes after ST15.

(ST16) At this time, in order to cancel the channel switching instructed in ST1 and execute the application task AT2, notification of the deletion of AT1 is made to the MM (ST16).
(ST17) Notification of AT1 deletion is transmitted to AT1. Since AT1 has already instructed execution of process 1, it is in a state where it cannot be erased and does not give any instruction.
(ST18) Thereafter, the process 1 responds to the MM.
(ST19) After notification of AT1 deletion, EM notifies MM to generate AT2.
(ST20) Upon receiving the notification of generation of AT2, MM generates a task of AT2.

(ST21) AT1 issues a request_AT1 to the MM to execute the driver task DT2.
(ST22) The MM sends a request_MM2 to the DT. At this time, the fact that task AT2 is waiting for a response from DT is stored in RAM 11.
(ST23) Based on request_MM2, DT starts execution of process 2 (process2).

  After execution of process 2, the MM receives a response to end execution of process 1. At this time, the MM searches the response processing information 31 and detects that a deletion request has already been issued for the process 1. When it is detected that this request is issued, the MM does not transmit this information to the application task AT2 even if it receives a response to the completion of the execution of the process 1. Thereby, the AT 2 does not mistake the end of the process 1 as the end of the process 2. Therefore, when receiving a response to end the process 2, the AT 2 can reliably detect the execution result of the process 2.

  (ST24) Thereafter, the MM receives a response of the end of the process 2 from the driver task DT. In this case, even if the process 2 is abnormally terminated, the result of the execution of the process 2 can be reliably detected as described above. Therefore, for example, even if the process 2 cannot be performed after the process 1 is executed, the process 2 can be returned to the state before the process 1 is executed, and then the process 2 can be executed again. . Therefore, it is possible to prevent the user from making any response to the user's operation from the operation unit 9 or ignoring it without taking corrective action.

  After ST24, the message management task MM may respond directly to the event manager EM with the status of ST24, or AT2 may receive the end of process 2 from the MM and return it to the event manager EM. .

  Next, the correction processing of the response processing information 31 when the task is deleted in ST16 of the flow of FIG. 5 will be described using FIG. FIG. 6 shows a list of information 31. As shown in FIG. 6A, if the list n + 1 is deleted in ST16, the addresses of the list n and the list n + 2 are linked as shown in FIG. 6B. For this purpose, the address 311 of the list n + 1 described in the list n is changed to the address 313 of the list n + 2, and the address 312 of the list n + 1 described in the list n + 2 is changed to the address 314 of the list n. Since they are linked in this way, the response processing information 31 can have a series of array structures, and it can be easily retrieved that the list n + 1 has been deleted.

  The subscripts n and n + 1 described above with reference to FIGS. 4 and 6 are for convenience of explanation, and in the implementation, each list is simply connected by indicating the addresses of the adjacent lists. There is no need to describe the response processing information 31 or the M2 program using subscripts. Also, the list does not require that the addresses are continuous. In the above, a bidirectional list is used as the list of information 31, but a one-way list format in which addresses are linked in either ascending order or descending order may be used. Further, the list format is not essential for carrying out the present invention, and it is sufficient that the response processing information 31 can be searched. However, it is desirable to describe the information 31 in the list format because the information 31 can be easily searched if the data is described in the list format.

  A combination of the RAM 11 and the ROM 12 of this embodiment corresponds to a storage unit of the present invention. The application and device driver of the present embodiment correspond to the upper program and the lower program of the present invention, respectively. The message management program 3 stores the message, the message management program 3 searches the list, searches for a match, and does not notify or blocks the response to the AT 2. Equivalent to.

  The configuration of FIG. 2 and FIG. 3 and the configuration of the program are examples, and may include another driver, application, and external device, or may not include all of them. The ROM and RAM may not be included in the microcomputer core, or may be a memory connected to the outside. It suffices if the processor and the program can be configured so that the device functions. In the above description of FIG. 2, the television has been described as an example. However, the present embodiment can be applied to any electronic device that executes an application using a device driver, even if it is not a television. Furthermore, the present embodiment can also be applied to the exchange of messages between the upper-level program and the lower-level program that are in a master-slave relationship, even if the electronic device does not necessarily have a device driver or an application.

  In the above description, the blocks separated for each function have been described. However, in the implementation, any of these functions may be configured by a system IC in which a plurality of functions are integrated, or one block may be divided into a plurality of blocks. You may comprise separately. For example, the present invention can be applied even when a device driver or a lower-level program is stored inside a sub processor outside the main processor 1. Specifically, a sub processor or a microcomputer may be provided in the receiving unit 41 and a device driver may be executed therein. In this case, the device driver or the lower program is executed by communicating with the sub processor. Then, a message management task MM can be provided inside the main processor, and communication with the sub processor can be stored in the format of FIG. Even if a response is received from the sub-processor, the device driver task that has already been canceled is not notified to the application as described in FIG. In such a case, the combination of the main processor and the sub processor corresponds to the task processing unit of the present invention.

  In the above embodiment, the program has a hierarchical structure, the event manager calls the application, the application calls the device driver, and the message management task MM is interposed between them. However, when a lower-level device driver resides in the RAM 11 and a request is received from a higher-level application, the task may be executed in response to an event of the request. In particular, when a device driver is stored in the sub-processor, the device driver may be always in an operating state and a task may be executed in response to a request from an application. This requirement corresponds to the requirement of the present invention.

The flow of the conventional task processing is shown. The block configuration of the television of this embodiment is shown. The procedure in which the television of this embodiment calls a program in order to process a task is shown. An example of the data structure of the information for response processing used by the task processing of the television of this embodiment is shown. The flow of the task processing of this embodiment is shown. A method for correcting a list when a task of this embodiment is deleted will be described.

Explanation of symbols

1-main processor, 10-CPU, 11-RAM, 12-ROM,
13-Event manager, 16-Application A,
17-Application B, 18-Application C,
21-Reception driver, 22-Image control driver, 23-Audio driver,
3-message management program, 31-information for response processing,
41-receiving unit, 42-image processing unit and display unit, 43-audio processing unit,
9-Operation part, EM-Event manager, AT-Application task,
DT-Driver Task, EOS-End of Sequence,
MM-Message management task

Claims (7)

A storage unit that stores an upper and lower program group having a master-slave relationship, and an event manager program that calls and executes these programs in response to a predetermined event;
A task processing unit that executes the program group, and the task processing unit performs task processing of a lower-level program based on a call or a request that is performed in accordance with execution of the higher-level program, and the lower-level program In the task management device that obtains the completion response of the task by the upper program,
When the task processing unit performs the call, request, or response between the upper and lower programs and the event manager, the task processing unit intervenes between these programs to transmit the call and response delivery. Executing a message storage program for storing communication information including the response name for identifying the response of the lower-order program for each task.
The task processing unit determines whether or not an instruction for canceling a task already being executed by a lower-level program is received from the event manager, and if a response is received from a task receiving the cancellation instruction, A task management device that executes a message blocking program that does not notify a response to the program or blocks the response.   The task processing unit has a list format in which, as the communication information, a list that lists the contents of communication information and a pointer that links a plurality of lists into an array structure by executing the message recording program are described. The task management apparatus according to claim 1, which is stored in the storage unit.   The task processing unit includes an API (Application Programming Interface) message name describing an instruction to be sent from a higher-level program to a lower-level program in addition to the response name as the communication information by executing the message recording program, and an application The task management apparatus according to claim 1, wherein the storage unit stores the data set including an application ID (identification) for identifying the application ID.   When the task processing unit receives an instruction to cancel the task of the higher-level program from the event manager, the message processing program uses the message storage program to delete the list corresponding to the task that has received the cancellation instruction, The task management device according to claim 2, wherein pointers before and after the list are corrected. The storage unit stores an application as the upper program and a device driver as the lower program,
The task management device according to claim 1, wherein the task processing unit executes the message storage program when calling and responding between an application and a device driver. A receiver that receives the broadcast and outputs a video signal;
A video processing unit for processing the video signal,
The storage unit stores, as a device driver, a reception driver that controls the reception unit and a video processing driver that controls the video processing unit, and a channel switching application that describes a series of channel switching operations as the application. Remember
The task management device according to claim 5, wherein the task processing unit generates tasks for the reception driver and the video processing driver when a channel switching application is executed. Using upper and lower program groups having a master-slave relationship, a storage unit that stores the program of the event manager, and a task processing unit that executes the program group,
The task processing unit executes an event manager to call and execute these programs according to a predetermined event, and a task generation step,
The task processing unit, a request step for calling or requesting in accordance with the execution of the upper program,
A lower-level program task step for performing task processing of a lower-level program based on a call or request by the request step;
In a task management method for executing a response step of acquiring a response of completion of a task processed in the lower program task step by an upper program,
In the task generating step or the lower program task step or the response step, the task processing unit is interposed between the upper and lower programs and the event manager to transmit the call and response delivery. When,
A message storage step of storing communication information including a response name for identifying the response of the lower-order program for each task, which is communication information for transfer in the transmission step;
The task processing unit determines whether or not an instruction for canceling a task already being executed by a lower-level program is received from the event manager, and if a response is received from a task receiving the cancellation instruction, A task management method for executing a blocking step of not reporting a response to the program or blocking the response.

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