JP2533970B2 - Display controller - Google Patents

Description

[Detailed Description of the Invention] [Outline] One physical line is used by using an ISDN network or a packet switching network.
Or, regarding a display control device capable of connecting a plurality of display devices and a plurality of host computers, it is an object to reduce the installation cost and maintenance cost of the line equipment for one display subsystem to communicate with the plurality of host computers. Then, the communication control means for communicating with a plurality of host computers, the means for managing the correspondence information between each window of the display device connected thereunder and the destination host computer that handles it, and the request from the display device, A logical switch control means for switching correspondence information between a window and a destination host computer is provided, and each window in one or a plurality of display devices is connected to a different host computer or the same host computer.

[Industrial applications]

The present invention relates to a display control device that uses an ISDN network or a packet switching network and can connect one or a plurality of display devices and a plurality of host computers with one physical line.

Online network systems have come to be used in various forms. In an online network mainly for distributed processing, data entry and inquiry operations are performed from one display device to multiple different host computers. Requests are coming out.

[Conventional technology]

Conventionally, when the display device is connected to a plurality of host computers, for example, the form shown in FIG. 4 is used.

In the case of FIG. 4 (a), each host computer H1, H2, ...
For this purpose, display devices U1, U2, ... are individually prepared, and are connected by dedicated lines.

In the case of FIG. 4 (b), one display device U1
Host computer H1 or host computer H2
The host computer to connect to when used by connecting to
Switch between H1 and H2 for use.

In the cases of FIGS. 4 (a) and 4 (b), one display device U1 cannot be used by being connected to a plurality of host computers H1 and H2 at the same time. Therefore, when using by connecting to a plurality of host computers H1 and H2, for example, as shown in FIG. 4C, the display device U1 is connected to the host computer H1 and the host computer H1 is connected.
When a request is made from the display device U1, the data is forwarded to another host computer H2 via the communication control processing device 40 to carry out the intended work. That is, the function of the host computer H2 is provided to the display device U1 by way of the host computer H1 that accommodates the display device U1.

This method has a problem that the load on the host computer H1 increases.

[Problems to be Solved by the Invention]

The present invention, in an online network composed of a plurality of host computers, does not increase the load on each host computer, and the equipment installation cost and maintenance of a line for one display subsystem to communicate with each host computer. For the purpose of reducing the cost, many host computers and many display devices can be connected through one physical line to improve the line concentrating effect.

[Means for solving the problem]

 FIG. 1 is a block diagram showing the principle of the present invention.

In FIG. 1, H1 to H3 are host computers having a data processing function, 10 is a network such as an ISDN network or a packet switching network, 11 is a display control device, and 12 is a communication control unit having a communication function with a plurality of host computers. Reference numerals 13 and 13 denote logical switch control units, 14 denotes a logical switch table that manages correspondence information between windows and host computers that handle the windows, U1 and U2 denote display devices, and W1 to W4 denote windows.

The communication control unit 12 with a plurality of host computers, for example, by multiplexing the control table necessary for communication,
The communication control program and the higher-layer protocol control program are operated as if a plurality of display control devices share one line.

Further, by utilizing that the display devices U1 and U2 have a multi-window function, information for connecting the windows W1 to W4 and arbitrary host computers H1 to H3 is provided.
Stored in the logical switch table 14.

The logical switch control unit 13 has a function of changing the connection between the communication destination host computer and the window by updating the logical switch table 14 in response to a request from the display devices U1 and U2.

[Action]

In recent years, networks such as ISDN and packet switching that logically have multiple communication channels on one physical line have become widespread, and one physical line enables simultaneous communication with multiple host computers H1 to H3. It has become.

The present invention utilizes this to make use of the host computers H1 to H3.
From the above, one display control device 11 can be viewed as a plurality of virtual display control devices.
Prepare a mechanism to separate communication destinations within 11. Then, each window is connected to the virtual display control device by a logical switch, so that a plurality of host computers H1 to H3 and a plurality of windows W1 are connected through one physical line.
~ Connect with W4.

Further, by changing the contact of the logical switch by the logical switch control unit 13, one window can variably communicate with any one of the connected host computers H1 to H3.

〔Example〕

FIG. 2 shows a configuration example of a display control device according to an embodiment of the present invention, and FIG. 3 shows a processing flow of an embodiment of the present invention.

In FIG. 2, the same symbols as those in FIG. 1 correspond to those shown in FIG. 1, 20 is a physical line, 21 is a communication mechanism for communicating with a host computer, and 22 is communication for controlling communication. A control program, 23 is a communication channel control table for controlling a communication protocol such as ISDN or packet switching, 24 is a higher-layer protocol control program for controlling the communication procedure according to the upper-layer protocol, and 25 is for executing and controlling the upper-layer protocol. Physical unit control table, 25a is a logical unit control table, 26 is a logical switch mechanism that correlates each window with a communication destination, 27 is a logical switch control program that controls switching of logical switches, 2
Reference numeral 8 represents a display interface unit that controls communication with the display device U.

In the present invention, the communication channel control table 23 and the physical unit control table 25 are prepared for the number of communications of the connected host computer. In the case of a packet network, the communication channel control table 23 has information such as a logical channel number, a subscriber address of a host computer / display controller, a protocol control element, etc., as shown in FIG. Similarly, the ISDN network also has information such as the type of communication channel and subscriber address.

Further, in order to control the virtual display control device and the display device U, it has a physical unit control table 25 corresponding to the communication channel control table 23. A logical unit is defined for each of the windows W1 to W4 of the display device U, and a logical unit control table 25a for managing the logical unit is provided in each physical unit control table 25. The logical unit control table 25a manages information such as the connection status of windows.

Communication with one host computer is performed using the communication channel control table 23 and the physical unit control table 25 including the logical unit control table 25a corresponding to each window. This communication channel control table 23
A plurality of virtual display control devices are configured in the display control device 11 by providing a plurality of and physical unit control tables 25 and multiplexing them.

The logical switch consists of multiple physical unit control tables 25
And a window which is a unit of a logical display screen. For its management, a logical switch table 14 is provided corresponding to each window.
The logical switch table 14 has information such as a logical unit number and a connected host number, as shown in FIG.

In response to a request from the display device U, the logical switch control program 27 rewrites the connected host number stored in the logical switch table 14, in other words, the connected virtual display control device number.

The connection host number in the initial state is set when the display subsystem is installed and stored in a storage device (not shown). Then, when the control program is loaded, the stored information is set in the logical switch table 14.

The display control device 11 performs a polling operation with respect to the display device U in order to monitor the state of the display device U, and when a request for switching the host computer during communication is recognized from the polling response, a logical operation is performed. Operate the switch control program 27,
The connected host number of the corresponding logical switch table 14 is updated.

When a window and the logical unit control table 25a in the physical unit control table 25 are not connected by the logical switch table 14, the window is displayed to the host computer in a power-off state. Therefore, when the logical switch table 14 is rewritten, the disconnected logical unit side transitions to the power-off state, and the connected logical unit side transitions to the power-on state.

As described above, the virtual display control device corresponding to the communication channel in one physical line 20 realizes sharing of the window by a plurality of host computers.

Next, referring to FIG. 3, the flow of processing of the part related to the present invention by the display control device 11 shown in FIG. 2 will be described. In the following description, ~ corresponds to the processing ~ shown in Fig. 3.

Polling of the display device is performed via the display interface unit 28.

Determine if there is a request to change the host computer connected to the window. If not, other processing is performed as necessary, and the processing is returned to and polling is repeated.

If there is a request to change the connected host from the display device, change the connected host number in the logical switch table 14 to
Change as required.

The logical unit control table 25a corresponding to the request source in the physical unit control table 25 is obtained, and the information such as the connection status of the corresponding window is updated. That is, the previously connected host computer side is turned off. Also, power on the newly connected host computer.

Power off notification is sent to the previously connected host computer through the communication channel.

Power on notification is sent to the newly connected host computer through the communication channel.

It should be noted that, especially when the display device does not have an interface for directly issuing a request to change the connected host, whether the display controller 11 has a connection host change menu display request by the polling operation to the display device before the above processing. It is also possible to stabilize the situation and display a predetermined connection host change menu when a display request is made, thereby receiving the connection host change request from the display device.

〔The invention's effect〕

As described above, according to the present invention, by the spread of high-speed and high-quality networks such as ISDN and packet switching,
Utilizing the ability to connect to multiple host computers at the same time with one subscriber line (one physical line),
Connect many display devices to one subscriber line,
Since it is possible to communicate with a plurality of host computers, it is not necessary to individually provide line equipment and terminal equipment, and equipment costs and maintenance costs can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a configuration example of a display control device according to an embodiment of the present invention, FIG. 3 is a processing flow of one embodiment of the present invention, and FIG. Indicates. In the figure, H1 to H3 are host computers, 10 is a network, 1
1 is a display control device, 12 is a communication control unit with a plurality of host computers, 13 is a logical switch control unit, 14 is a logical switch table, U1 and U2 are display devices, and W1 to W4 are windows.

Claims (1)

(57) [Claims] 1. A host computer (H1, H2,
A display control device (11) for controlling a display device (U1, U2, ...) Having a multi-window function, which is connected to ...), and includes a communication control means (12) for communicating with a plurality of host computers, Means for managing the correspondence information between each window of the display device connected to the computer and the communication destination host computer that handles it (14), and a logic for switching the correspondence information between the window and the communication destination host computer in response to a request from the display device. A display control device comprising switch control means (13), wherein each window in one or a plurality of display devices is simultaneously connected to different host computers or the same host computer.