JPH08297580A - Input/output control method - Google Patents

Abstract

PURPOSE: To enable a program of user level to handle data that need to be inputted or outputted in real time in case of emergency by resetting privilege protection according to mode transition, allocating a CPU resource preferentially to a specific user program, and making the specific user program have an input/output device directly under its control. CONSTITUTION: If an emergent event which requires real-time processing is generated, an OS 15 freezes and saves a program which currently runs in a memory or secondary storage, and releases the input/output device where the event occurs from being protected. Further, the specific user program 19 is given priority which is high enough to process the event, and the control is passed to the specific user program 19. Requests to other lower-speed input/ output devices are held thereafter by the OS 15. Then, the user program 19 accesses the input/output device directly to perform processing preferentially. After the processing ends, the specific user program 19 returns the control to the OS 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling an input / output device in a high performance electronic device such as a workstation or a personal computer.

[0002]

2. Description of the Related Art In a system providing multi-user / multi-task, (1) I / O processing is performed by an OS (operating system), and since the OS operates in privileged mode, The operating user program could not directly read or write data from the input / output device. Therefore, when the user program inputs and outputs, it is necessary to issue an SVC (supervisor call) to the OS. Since the SVC has to switch the operation mode, it is necessary to save the current operating environment (context) of the user program in the memory. If there is a lot of context information or if the SVC is executed frequently, it takes a lot of time to process it. It was being done.

(2) Until the OS actually controls the input / output device and reads the data and passes the read data to the user program, or the user program passed the OS to the user program that emitted the SVC. It is usual to actually write data to an I / O device and wait until the OS notifies that the writing is completed, and the I / O processing time was different depending on the system environment or load condition. I had the problem.

[0004]

However, in the above-mentioned conventional example, it is impossible for the user program to directly access the input / output device and to realize high-speed interrupt processing at the user level on the existing CPU architecture. Therefore, it is not possible to reliably determine that a specific user program has completed input / output processing by a certain time, and execute time-dependent input / output data such as audio data or image data. It has the drawback that it cannot be processed in time.

An object of the present invention is to provide input / output control that solves the above problems.

[0006]

Means (and Action) for Solving the Problems
Means for causing a mode transition to an input device requiring real-time processing, and means for notifying the OS of an input / output device requiring a real-time processing from a specific user program and causing a mode transition, Mode transition removes privilege protection so that a specific user program can access the I / O device, preferentially allocates CPU resources to the specific user program, and allows the specific user program to directly control the I / O device. Means for releasing the CPU resources and the I / O device and returning the I / O device to the original protection mode when the real-time processing is completed,
It is realized by having.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a drawing which best represents the features of the present invention.

A normal input / output mode is shown in the upper part of FIG. 1, and an operating system (hereinafter referred to as an OS) manages all input / output devices so that all are accessed in a privileged mode. User programs that are protected by the OS and that directly access these devices are forcibly terminated by the OS.

When a notification of an input event from an input / output device that requires real-time processing or a request for control of a specific input / output device from a specific user program is sent to the OS, the OS displays the information shown in FIG. The system transits to the emergency I / O mode shown at the bottom, removes the privilege protection of the specified I / O device, and the user program can directly handle the I / O device.

Moreover, since the OS gives a high priority to a specific user program and passes control to the user program, the CPU can be preferentially used and the processing in real time becomes possible.

Furthermore, by returning to the state before the emergency processing mode when the processing is completed, a more flexible multi-user / multi-task environment can also be provided.

FIG. 2 shows the flow of control and input / output data in the case of emergency input processing.

In FIG. 2, when an urgent event requiring real-time processing occurs, the OS freezes the program that has been operating up to now and saves it in the memory or the secondary storage, and the input / output at which the event occurred. Remove protection from equipment.

Further, the priority required for processing the event is set in the specific user program, and control is passed to the specific user program.

Thereafter, the OS suspends requests for other low-speed I / O devices.

After that, the user program directly accesses the input / output device and preferentially performs the processing. When the processing is completed, the specific user program returns control to the OS.

After that, the OS restores the protection of the input / output device to its original state, and if necessary, allocates CPU resources to the frozen program to transfer control, or performs a low-speed input / output processing in a suspended state, thereby performing normal operation. Return to the processing of the OS.

FIG. 3 shows the flow of control and input / output data in the case of emergency output processing.

In FIG. 3, when a specific user program preferentially occupies a specific input / output device, first the OS
Notify that to. If possible, the OS removes protection from the designated input / output device, sets the priority required for output processing, and returns control to the specific user program. Similar to the input processing, requests for other low-speed I / O devices are suspended thereafter.

The specific user program directly accesses the input / output device to preferentially perform the processing, and when the processing is completed, returns the control to the OS.

The OS restores the protection of the designated I / O device, restores the priority of the specific user program if necessary, or performs the low-speed I / O processing in the pending state to perform normal OS processing. Return to.

Further, even when the start time of the input process is known in advance, it is possible to give control to a specific user program in advance and process it preferentially.

[Other Embodiments] In a multi-processor system, by assigning a fixed CPU in advance when this specific program is started, it is possible to perform parallel processing with other programs, and it is possible to perform parallel processing with other programs. It is possible to perform input / output processing in real time without affecting the program.

[0024]

As is apparent from the above description, according to the present invention, in an environment of multi-user / multi-task, in an emergency, a user-level program can follow the real time such as voice data and image data. Since data that requires input / output processing can be handled, a more flexible system configuration can be realized. in short,
The present invention can be variously modified and implemented without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is a drawing showing the features of the present embodiment.

FIG. 2 is a diagram showing an input process of this embodiment.

FIG. 3 is a diagram illustrating an output process.

[Explanation of symbols]

 11, 15 operating system 12 input / output device group 13, 18 ordinary user program 16 input / output device group 17 input / output device group 14, 19 specific user program

Claims (2)

[Claims] 1. A means for causing a mode transition for an input / output device that requires real-time processing, and a specific user program that notifies the operating system of the input / output device that requires real-time processing, By means of causing a transition and mode transition, privilege protection is removed so that a specific user program can access the I / O device, CPU resources are preferentially allocated to the specific user program, and the specific user program directly inputs and outputs. An input / output control device having means for putting the device under control and means for releasing the CPU resource and the input / output device and returning the input / output device to the original protection mode when the real-time processing is completed. . 2. A means for causing a mode transition to an input / output device requiring real-time processing, and a specific user program notifying the operating system of the input / output device requiring real-time processing, The mode transition process that causes a transition and the mode transition remove the privilege protection so that a specific user program can access the I / O device, preferentially allocate CPU resources to the specific user program, and the specific user program directly An I / O control method comprising the steps of placing the I / O device under control and releasing the CPU resources and I / O device to return the I / O device to the original protection mode when the real-time processing is completed.