JPH0432413B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a method for modifying software, and particularly to a method for modifying software in an online system.

[Prior Art] It is not permissible to temporarily stop an online process control system while it is in operation because it causes confusion in society and causes a loss of trust among users.

Therefore, if it becomes necessary to modify a program during online operation, the modification must be done without stopping the system. However, in conventional modification methods, when you specify the address and its contents to be modified, the memory contents are immediately changed, regardless of whether the program area at the address to be modified is running or on standby. It was. Therefore, if the timing of correction is shifted by microseconds, the system may go down, or a program that has not yet been corrected may be executed, which may cause the program to run out of control.

Such a dangerous memory modification system was extremely inconvenient considering the amount of social unrest caused by problems with online systems.

[Objective of the Invention] In order to improve the above-mentioned conventional drawbacks, the present invention provides a software modification method that can be modified while the system is in operation without causing any trouble. It is in.

[General Description of the Invention] In order to achieve the above object, the present invention provides that when a modification execution command is input after completing the specification of all items to be modified at the same time, to which memory area of the program (task) the modification specified area belongs. It checks when the program to be modified is not in the middle of execution (including during suspension), instantly inhibits the execution of the program, and allows execution of the program again after completing all specified modifications. The feature is that the software can be completely modified without stopping the system at all.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a system configuration diagram of an embodiment. Electronic computer (CPU) 1 is storage device (memory) 2
It has a data line or a signal line 7 to control a control object 3 such as a process. It also has a man-machine interface via a command/response device 4 such as a console consisting of a display 5 and a keyboard 6.

FIG. 2 is a block diagram of the memory. The memory 2 includes an OS (operating system) program 21, an OS table 22, a modification execution subroutine 26, a modification management table 27, a modification main program 28, and application programs and tables 29 that differ depending on the controlled object 3. is placed. The OS table 22 includes a task state management table 24 and a task area management table 25.
It includes task management data 23 consisting of. Application program and table 2
9 is an area for each task such as an area 30 for task i and an area 31 for task j, and a common table 32.
It consists of common areas between tasks such as

FIG. 3 is a configuration diagram of the task status management table 24. The task state management table 24 is composed of execution state control words for each task, such as the task i state control word 241. The execution state control word of each task, for example, the task state control word 241, includes a task execution display flag (1 when the task is running, 0 when it is not running) 242, and a task waiting state (WAIT state).
Display flag 243 (1 when task is in WAIT,
Contains 0) when not WAIT.

FIG. 4 is a configuration diagram of the task area management table 25. The task area management table 25 is
Task i starting number 251 and task i ending address 25
It consists of a pair of the start address and the end address of each task area (program and dedicated table for each task) as shown in FIG.

FIG. 5 is a configuration diagram of the modification management table 27. The correction management table 27 includes a correction status word 271 for displaying the correction execution status (correction in progress, correction execution normally completed, correction execution abnormally completed, etc.), and a correction task number 27 for displaying the task number being corrected.
2. The number of correction areas 273, the correction area head address 274 existing corresponding to each correction area, the correction area length 275, and the correction value 276 (stored continuously by the correction area length).

FIG. 6 shows a modification command input response output program,
That is, this is the control flow of the modified main program 28. This program operates as one of the tasks managed by the OS21. Its functions include inputting a modification command, checking it, pointing out errors in the modification command to guide the input of highly reliable modification commands, editing the input modification command and setting it in the modification management table 27, It requests the modification execution subroutine 26 to perform modification according to the modification command, and outputs the modification execution result as a response message.

In FIG. 6, first, a modification command is input in step 602, and if the command is related to modification content, conditions regarding the modification area and modification content are set in the modification management table 27 in step 603. In the case of a modification execution command, the task area management table 25 is checked in step 604 to see if the modification command area is a task area other than the designated task. If there is a task area other than the designated task in the modification command area, a modification area designation failure message is output in step 605, and a modification command input is awaited. There are three types of designated defective messages: I (execute as is), E (stop modification), and R (re-enter modification execution command). When I is output, there is a case where there is no task area other than the specified task in the modification command area. Similarly, the process moves to step 606. When E is output,
In step 607, a correction stop message is output. Further, when R is output, step 602
Go back and re-enter the correction command. Step 606
Then, set the modification status word to modification request state, output a modification execution start response, and wait for modification completion notification from the modification execution subroutine linked to the OS task scheduler. Next, in step 608,
Upon receiving the modification completion notification, the modification result is output as a response message.

FIG. 7 is a control flowchart of the modification execution subroutine.

This subroutine is linked to the exit of the task scheduler 211 of the OS 21, and is called when the execution task is switched, just before control is passed to the next executable task. Then, in step 702, it is determined whether or not there is a modification request. If it is in the modification request state, then in step 703 it is determined whether or not the modification command task is in the execution state. If it is not in the execution state, further, in step 704, the modification command task is issued. Determine whether the task is in a waiting state. When the modification command task is not in a waiting state, the contents of the specified area are modified in step 705. In that case, the specified area (information about the correction area 2
The contents of the area specified in 73 to 275 are corrected to the specified correction value 276, the correction completion status is set to the correction status word 271 in step 706, and the correction command/response program (correction main program 28) is set in step 707. Notify that the correction has been completed.

FIG. 8 is an operation flowchart of an embodiment of this method. The operation of this embodiment will be explained with reference to FIG.

When the request key on the keyboard 6 is pressed, a modification command input response output program, that is, a modification main program 28 is activated. The modification command input response output program (hereinafter abbreviated as modification command response program) moves the pointer on the display 5 to the beginning of the next line (hereinafter referred to as line feed), displays , moves the pointer to the next line, and displays ( (hereinafter referred to as a response), and waits for a command input of the correction area address (step 800).

When the correction area start address is input, the correction command response program 28 inputs the correction area start address 27.
4, the input address is set and the current memory contents at that address are displayed on the display 5. Furthermore, after that, a ":" is displayed, the pointer is moved past the ":", and the user waits for the input of the content to be corrected (step 801).

When “Modification content LF” is input, the correction command response program 28 displays “SP Contents of the next address:” after a line break and waits for input of a content correction command for the next consecutive address (Step 802, 8
03 loop).

When “Modification content CR” is input, the correction command response program 28 responds with “” after a line break, and selects the starting address of the new correction area (which does not need to be connected to the already specified correction area). Waits for key-in of modification execution request (step 802,
Step 804).

If there are still new areas that need to be fixed all at once,
The starting address of the new correction area is input, and the operations from block 801 are repeated for the new correction area.

When the designation of the areas to be collectively corrected is completed, a correction execution command, ie, "S task number CR" is keyed in. Modification command response program 28
inputs this and sets the correction task number 272, and also refers to the task start address 251 and end address 252 of the task area management table 25 to place the correction in the correction area set in the correction management table 27. It is checked whether there is a task included in the task area 31 of a task that is not set to the task number 272 (not designated for modification), and if there is no such task, a response is sent to start modification execution. That is, after a line break, “COMMAND
OK.MODIFY, START・” on display 5
The correction status word 271 is set to a correction request state (all bits are 1), and a correction completion notification (POST) from the correction execution subroutine 26 is waited for (steps 805 and 806).

When the modification state word 271 enters the modification request state, as already mentioned in the explanation of FIG.
The modification execution subroutine 26 linked to the exit of the task scheduler 211 of No. 1 determines whether the task set in the modification task number 272 is running or WAIT.
The corrections set in the correction management table 27 are performed all at once by grasping the timing when the correction is not in progress, the correction result is set in the correction status word 271, and the correction command response program 28 is POSTed (notifies correction completion) when the correction is completed. .

Thereafter, the modification command response program 28 operates and outputs a modification completion message. That is, after the line break, "MODIFY NORMALLY, END" is displayed on the display 5 as a response.

By checking the rationality of the correction area in block 805, correction task number 272 is found in the correction area.
If there is something included in a task (for example, i) other than the task (for example, i) set to , the modification command response program 28 warns that the modification command is defective. That is, after a line break, “COMMAND
"ERROR: ENTER I, E, R:" is displayed on the display 5, and the input of any one of I, E, and R is awaited (step 808).

When “I” which means IGNORE is input,
The warning is ignored and operations continue from step 806 onwards (see Figure 6).

When "R" meaning RETRY is input (FIG. 6), the process returns to block 804 and waits for the input of a correction execution command again. At this time, the task number of the new modification execution command is set in the modification task number 272, and the rationality check of the modification area is again performed on this task number.

When “E” meaning END is input (6th
(Figure), the modification command response program responds to stop modification. In other words, after a line break, “END DUE TO
COMMAND ERR” response and exit the program without performing any modifications.

〔Effect of the invention〕

According to the present invention, changes to the programs constituting one task and the local data of the task are specified all at once, and the timing when the task is not being executed or suspended (due to waiting for input, etc.) is automatically found. This makes it possible to modify programs while the system is running without causing any trouble, increasing the reliability of the system.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a system configuration of an embodiment of the present invention, FIG. 2 is a diagram showing a memory map of the embodiment,
Figure 3 shows the configuration of the task status management table, Figure 4 shows the configuration of the task area management table, Figure 5 shows the configuration of the modification management table, and Figure 6 shows the modification command input response output. Flowchart of the program (correction main program), Figure 7 is a flowchart of the correction execution subroutine,
FIG. 8 is an operation flowchart of this embodiment. 1...CPU, 2...Memory, 3...Controlled object, 4...
Command response device, 5... Display, 6... Keyboard, 7... Data line, signal line, 21... OS program, 22... OS table, 23... Task management table, 24 Task state management table, 25...
Task area management table, 26... Correction execution subroutine, 27... Correction management table, 28...
Modified main program, 211...Task scheduler, LF...Line feed, CR...Return, SP...Blank.

Claims (1)

[Claims] 1. In a computer system that has a management program that manages the logical storage space occupied by tasks to be executed, multiple items within a task to be modified at the same time are specified, and a modification execution command is used to specify the storage area to which the task containing the items belongs. Determine the timing when control is passed to the management program, check whether the task has started but has not completed execution using the task management information in the management program, and determine whether it is before execution or not. All correction items specified for a task in the completed state are momentarily inhibited from executing the task before passing control to the task, and the task is corrected all at once, and the task is executed after the correction is completed. A software modification method characterized by restarting the software.