JPS6371735A - Multitask operating system - Google Patents

Abstract

PURPOSE:To obtain a multitask operating system OS where two tasks which issue processing requests can be operated in parallel, by classifying processing requests to the OS into console input/output requests and the other requests and providing a means which retracts internal states of the OS in places different between these two classifications and restores them at the time of release of queuing. CONSTITUTION:An exclusive control means classifies processing requests to the OS into console input/output requests and the other requests and exclusively controls them. The restoring means retracts the internal states of the OS in places different between said two classifications of processing requests at the time of queuing in the OS and restores them at the time of release of queuing. Thus, the degree of multiplexity is increased with a simple means in the multitask OS which is based on a single-task OS and to which the multitask function is added.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a multitasking operating system for busy computer equipment, and is particularly suitable for use when converting a single-tasking operating system into a multitasking system. .

[Conventional technology]

The existing single-task operating system (hereinafter the operating system will be abbreviated as O8),
There is a strong demand for multitasking in communication programs, etc. To achieve this, there have conventionally been the following three methods.

The first method is to create a multi-task O8 with external specifications adapted to the single-task O8. this is,
Since the internal specifications are created with multitasking in mind from the beginning, advanced multitasking control is possible.The second method is to create the core of the multitasking OS as one application program under single-tasking O8. This is how to make it work. Since the single task O8 itself cannot process requests issued by multiple tasks (programs) at the same time, it is treated as one resource and used under exclusive control so that only one task uses the O8 during construction. This is illustrated in FIGS. 4 and 5.

That is, as shown in FIG. 4, single task O81
A multitasking kernel 2 operates under this, and a user program 3 is executed under it. When the user program 3 makes an aS call for an input/output request, as shown in Figure 5,
First, in step 5a, single task O8 exclusive processing is performed, and the button is pressed so that other tasks cannot use single 08. After that, in step 5b, single O8 is called, and in step 5C, single O8 is released, and other tasks Enables use of a single OS.

The third method is to operate single task O8 as one task under a unique and simple multitasking O8,
Functions such as input/output control of the single task O8 are processed using the functions of the multitask O6. This is shown in FIG. There are several user tasks 4 under multitask 082, one of which is single task 0.
There are 81. Furthermore, there is a user program 3, which is busy, and the single OS call of this user program 3 is processed by the single 081 using the multitasking 1082 function.

[Problem that the invention seeks to solve]

The first method described above is equivalent to creating the entire OS from the beginning, which results in a very large cost.

In addition, the second method has the advantage of being able to multitask relatively easily.25ζOnly one task can use a single OS at the same time, so a task can issue a key human power request to a single OS and use a single OS. When a task is waiting for the user's key power inside, other tasks cannot use one single O8 due to exclusive control, so the multiplicity of tasks cannot be increased and CPU time is wasted. was there.

Furthermore, in the third method, the multiplicity of tasks can be increased, but the cost of developing a unique multitasking O8 is high, and only one user program 3 can be executed at the same time (user (Task 4 can be executed multiple times at the same time)
Multitasking 08 file management and singletasking 08
Although there are problems such as the difficulty of controlling the two files '[31 so as not to contradict each other, the purpose of the present invention is to develop multitasking 08 which is based on singletasking O8 and has a multitasking function added. The purpose is to provide a form that increases the multiplicity by simple means.

[Means for solving problems]

The above object is achieved by developing a conventional second method, namely operating the kernel of a multitasking O8 under a singletasking O8. The problem with this conventional method is that only one task can be performed at a time, and a single O8
The reason is that you cannot use . However, among OS calls, input/output requests other than key manual requests are completed in a relatively short time, whether for disks or printers, so when these requests are issued, K
Even if a call request is made to wait under exclusive control, it is not a big problem. The problem is that if a single OS is waiting for the user's key power after issuing a key power request, other tasks will not be able to use the single OS. Therefore, the key manual processing and other single O8 functions are processed in parallel. Firstly, the key manual processing is created independently outside the single O8, and the key manual processing does not use the single OS.Secondly, the inside of the single OS can be operated in parallel. There is a way to control it from the outside.

In the first method, although the key is manual processing, it is possible to use a single OS.
The processing contents are diverse and difficult to fully support, and the second method is easier to implement than this, so the second method is used.

That is, the feature of the present invention is that the existing single-task operating system K.

In a multitasking operating system that includes a core that performs multitasking control, there is an exclusive control means that performs exclusive control by dividing processing 'LIN' to the operating system into two types, console input/output requests and other requests, and an operating system. When the system enters a waiting state, the internal state of the operating system is saved in separate locations for each of the two types of processing requests, and a recovery means is provided to recover the internal state when the waiting state is released. This is because we have the necessary equipment.

[Effect]

Exclusive control is performed by dividing processing requests to 08 into two types: console input/output requests and other requests. The recovery means saves the internal state of the OB to separate locations for each of the two types of processing requests when the OB enters the waiting state in 08, and recovers it when the waiting state is released.

As a result, it is possible to provide a multi-task OS based on the single-task O8 with multiple task functions added in a form that increases the degree of multiplicity using simple means.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a control processing means according to the present invention.

When using OB functions from within an application program, issue an OEI call. The OS call processing includes the O8 exclusive processing in step 11.12 in Figure 1,
O8s release treatment in step 15.16, -17'? If the single 08 is waiting for input/output completion, step 1
Add the completion wait process in step 7. Now, from a certain task, O8
When a key human power request is issued, in step 10 it is determined that it is a key human power request, and in step 11 O8 is exclusively used for key human power.

Then, in step 3, a single O8 call is made, and when the key is put on hold, a completion waiting process is performed in step 17. If there is a key human power, the waiting state will be canceled and the train will return from single O8. Thereafter, in step 14, it is determined that there is a key human power request, and in step 15, the exclusive use of the OS regarding the key human power is released.

FIG. 2 shows the control means for waiting for completion processing. Single OB
When processing an input/output request from an application program within the application program, if the input/output operation has not been completed, this completion wait process is called. Step 2
If the input/output is not completed, if it is a key manual request, save the internal state of the single OB to the key manual buffer in step 22, and then wait for the input/output to complete. shall be. When a key is pressed and the input/output is completed, if it is a key manual power request, the internal state of the single O8 is recovered from the key human power buffer in step 26, and then the processing of the single O8 is continued.

An example in which key manual input and other OS calls are executed in parallel under the above control will be described with reference to FIG. First, when task A is running and a key human power request is output to O8 at step 71, O8 is exclusively occupied by the key human power, and after saving the state of the single O8 to the key human power buffer at T,
Waiting for key personnel. Next, task C starts running, issues a disk output request to the OS at T, dedicates O8 for other use, saves the state of the single O8 to the buffer for other use at T4, and waits for completion of disk output.

Since task C uses single O8 when task A is waiting inside single O8, task Adζ
The internal state of the single O8 while waiting for key human power is destroyed by the disk output process of task C, but this is saved in the key human power buffer, so it can be recovered later. It is possible. Currently, task A is waiting for key input, and task C is waiting for disk output to be completed. Busy task B starts to move, and when the key human power request is sent to the OS at T, task A is the key human power O8 at T.
Since task B cannot use O8,
Until the currently occupied task A releases the key human-powered OS, the key human-powered OS is released. Next, task D starts running and sends a disk input request to the OS at T. Since task C is monopolizing the OS for other use at T, task D cannot use O8, and the currently exclusive task C releases O8 for other uses, and waits for the release of the other OS.

At this point, tasks A, B, C! , D are all in a waiting state. Next, when the key is pressed at T, and the key human power waiting state is released, the internal state of the single O8 that was saved at T, is returned from the key human power buffer to the OS, and it is returned to the OS at the time of T. Single O after doing the same
Continue the key manual processing in step 8. Then, at the point where T, exits from the single O8, key manpower 08 is released. Then, T.

Task B was waiting for the key human power O8 to be released.
However, T started to move and monopolized the key human power 08%”16
After saving the status of the single O8 to the key human power buffer, the system waits for key human power. When the disk output is completed at Tml and the waiting state is released, the internal state of the single O8 saved at T4 is transferred from the other buffer to the O8K.
After returning it, continue the Dinuku output process. and,
When you exit Tit's Single 08, you will release the OS for other uses. Then, task D, which had been waiting for the other use 08 to be released at T6, starts moving from TH, monopolizes the other use 08, and performs disk input processing.

Since the control is performed as described above, as is clear from Figure 3, even though what runs inside the single O8 is always exclusively controlled by one task, the key human power and other processes are controlled separately. It becomes possible to operate in parallel by using the waiting time. This means that when waiting in O8,
This is done because the internal state of the O8 is evacuated and restored by dividing key human power and other processing requests.

Also, the sequence in Figure 3 is an example of an operation, and various cases can be considered depending on the timing of key presses and the timing of completion of disk output, but since a single Os is also inside an O8 in a broad sense, any arbitrary operation of a single O8 can be considered. At this point, there is no task switch, only when the task is in the waiting state.
Multitasking O8 provides control that enables task switching.
Since this is done in the nucleus, the sequence will be the same as in Figure 3 even if the timing is slightly off.

By doing the above, the single task O8 remains as it is, and by simply adding some processing programs externally, the two tasks that issued the key human power and other aS processing Sakai requests will run in parallel. This has the effect of making it possible to achieve multitasking O8.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to provide a multitask O8 based on a single task O8 with a multitask function added thereto, in a form that increases the multiplicity using simple means.

[Brief explanation of the drawing]

FIG. 1 is a processing flowchart showing an embodiment of the present invention;
2 is a flowchart showing the processing contents of the completion waiting process in FIG. 3, a time chart showing an example of the operating state of each task, FIG. 4 is a block diagram showing a conventional example, and
This figure is a flowchart for explaining FIG. 4, and FIG. 6 is a block diagram showing another conventional example. 1 Nishingel task OS, Z; core of multitasking O8,
3: User program (task), 10°11.12,
13: Exclusive control means, 21, 22°..., 27: Recovery means Fig. 1 $2.

Claims (1)

[Claims] In a multitasking operating system that adds a core for multitasking control to an existing singletasking operating system, processing requests to the operating system are divided into two types: console input/output requests and other requests, and exclusive control is performed. exclusive control means;
A recovery means that saves the internal state of the operating system to separate locations for each of the two types of processing requests when the operating system enters a wait state, and restores the internal state when the wait state is released. A multitasking operating system featuring: