JPS6242634A - System for connecting plural terminals to single line - Google Patents

Abstract

PURPOSE:To connect terminals, whose number exceeds the number of addresses assigned to terminals, to a single line even if the number of addresses assigned to terminals is limited, by extending the header part of a message to include a terminal address there. CONSTITUTION:Plural terminals 1201-120n are connected to a terminal equipment 100 to which a prescribed transmission slot is assigned for the purpose of transmitting and receiving data to and from a controller. A schedule of processings of processes of transmission and reception requests from each terminal 120, etc. is generated by a line control layer part 140 and is set to a process control table 130. When a transmission process is executed, the extended message header including the address of the terminal which issues the transmission request is added to a transmission text and is transferred to a line control program, and when a reception process is executed, a reception text is distributed to the terminal whose address is included in the extended message header.

Description

[Detailed description of the invention] 〔table of contents〕 The present invention will be explained in the following order.

A. Overview B. Field of industrial application C1. Prior art (Fig. 7) D1. Problem to be solved by the invention E0. Means for solving the problem (Fig. 1) F1. Effect F+. Expanded message Format explanation (second
Figure) F2. Effects of the present invention (Figs. 1 and 2) G, Examples (Figs. 3 to 6) G+, Explanation of configuration (Figs. 3 to 5) G2. Description of operation (Figures 3 to 6) Overview of H effect AC] In an online system where the number of addresses assigned to a terminal is limited and the line control program can service one process at a time, message By extending the header to include the terminal address, it was possible to connect multiple terminals to a single line, exceeding the allotted number.

B [Industrial Application Field] The present invention is applicable to applications where the number of addresses assigned to terminals is limited,
And in an online system where the line control program can service one process at a time,
This invention relates to a method for connecting a plurality of terminals to a single line, in which a plurality of terminals exceeding the allocated number are connected to a single line.

C [Prior Art] Conventionally, when connecting a plurality of terminals to a single line, this was done by inserting an appropriate branching device on the line.

FIGS. 7A and 7B show a conventional method for connecting a plurality of terminals to a single line. Note that the line control program can service one transmission or reception process at a time.

FIG. 7(A) shows a system in which each of the terminals Tal to Ta3 is directly connected to the host Ha by the respective line La+"La3, and a branching device Ba is provided on the line La+ of the terminal Ta1, and a branching device Ba is connected to this via the line La. terminal T a
This shows an example when 4 are connected.

FIG. 7(B) shows that each terminal T b 1 to Tb 3 is connected to the terminal control device TCb by each line Lbl-Lb3, and the terminal control device TCb and the host Hb are connected by a single line L b o. In a system where
This shows an example in which a branching device Bb is provided on the line Lb3 of the terminal Tb3, and the terminal Tb is connected to this via the line Lb+.

A necessary condition for connecting a plurality of terminals to a single line using such a terminal connection method using a branching device is that the protocol used for communication allows the existence of a plurality of terminals.

For example, the polling and selecting codes in the asynchronous procedure include a code indicating the address of the terminal, and S DLC (Synchronous Data
In high-level procedures such as aLink Control), a code indicating a terminal address is included in the protocol header of the frame. Therefore, by including a plurality of these address codes, it is possible to connect a plurality of terminals to a single line. However, if there is a limit to the number of addresses assigned by the address code, it is not possible to connect terminals exceeding the number of addresses assigned.

Furthermore, if the protocol does not allow the existence of multiple terminals, it is not possible to connect other terminals to a single line by means of a branching device. FIG. 1(C) shows an example of such an online system.

In FIG. 7(C), each terminal T C1 to Tc3 is connected in series to the terminal control device TCc by a common loop line Lcp, and the terminal control device TCc and the host Hc are connected by a single line Lco. There is.

In the online system shown in FIG. 7(C), once the system protocol is established, it is not allowed to increase the number of terminals since this would involve changing the protocol. Even if it were allowed, it would be extremely limited and difficult to implement in practice.

D [Problem to be solved by the invention] As mentioned above, in the conventional method of connecting multiple terminals to a single line, the number of addresses assigned to the terminal is limited, even when the protocol does not allow the existence of multiple terminals. If there is, there is a problem that it is not possible to connect more terminals than the allocated number to a single line.

The present invention provides a method for connecting multiple terminals to a single line, which makes it possible to connect a number of terminals exceeding the assigned number to a single line even if there is a limit to the number of addresses assigned to the terminals. The purpose is to

E [Means for Solving the Problems] The means taken by the present invention to solve the above-mentioned problems in the conventional method of connecting multiple terminals to a single line will be explained with reference to FIG. .

FIG. 1 shows the configuration of the present invention in blocks.

In FIG. 1, 10() is a terminal device connected to the single line 200, and each terminal Ta+ xTa:+, Tbt to Tb3 in FIGS. 7(A), (B), and (C)
This corresponds to P T Cr to T C3. The number of addresses assigned to the terminal device ff100 is limited to a fixed number.

Reference numeral 110 denotes a line control means that controls the connection between the single line 200 and the line control layer section, and its line control program can provide services for one process, such as transmission or reception, at a time.

Terminals 1201 to 120n consist of original terminals and newly connected subterminals.

In the description of the present invention, the original terminal and the sub-terminal are both referred to as a terminal without distinction.

130 is a process control table, each terminal 1201-1
A schedule for processing process requests such as transmission and reception requests generated from 20n and information necessary therefor are set.

140 is the line control lay part 1, and the process control table 1
30 to create a schedule for processing each process requested from each terminal 1201 to 120n and set it in the process control table 130. If the process to be executed is a sending process, an extended message header containing the address of the terminal that issued the transmission request is added to the transmission message and passed to the line control program, and if the process to be executed is a receiving process, Performs processing to distribute the received message to the terminal whose address is included in the extended message header of the received message.

F [Function] Prior to a detailed explanation of the present invention, an expanded message formant used in the present invention will be explained.

F+ (Explanation of message format extended to 7G) In order to avoid uniformity in the protocol and to be able to connect multiple terminals (as mentioned above, each terminal includes subterminals) to a single line. , each terminal and host or terminal control device T
It is necessary to give a terminal address that identifies each terminal to the messages flowing between C and C. That is, when the host or terminal control device TC receives a message from each terminal, it must identify which terminal the message was sent from. When a TC sends a message and receives it, it must identify which terminal the message should be distributed to, and in both cases, the terminal address is required to identify them. This is because.

In the present invention, in order to add this terminal address to a message, the header part of the message is expanded and the terminal address is included therein.

FIG. 2(A) shows a normal message format, and FIG. 2(B) shows an example of an expanded message format of the present invention.

A normal message format is formed of three parts: a protocol head, a message to the terminal, and a protocol tail, as shown in FIG.

The extended message format of the present invention is shown in FIG.
), the protocol head part was extended and the terminal address for identifying each terminal was inserted into this extended header part. By doing this, it is possible to include addresses for more terminals (sub-terminals) than the initially limited number without changing the protocol.

Note that a message that is sent using this expanded message format is called a transmitted message, and a message that is received is called a received message.

One possible method for extending such a message header is to change the application program of the host or terminal control device, but it is actually difficult to change the application program.

Therefore, as explained in the previous section, the present invention newly provides a process control table section 130 and a line control layer section 140 on the terminal 100 side, expands the functions of the terminal side, and expands the message header. It is composed of

F2 (Operation of the present invention) The process of message transmission or reception is carried out by the terminals 1201 to 1201.
120n issues a process request to the line control layer section 140.

The line control layer unit 140 analyzes the contents of the process request issued from the terminal, and uses the process control table 130 to schedule the transmission or reception process requested by the terminal.

If the process to be executed is a sending process, an extended message header containing the address of the terminal that issued the transmission request is added to the transmission message, and this transmission message is sent to the line control means 110.
give it to

If the executed process is a receiving process, the receiving terminal is identified from the terminal address included in the extended message header of the received message, and the received message is distributed to that terminal.

In the manner described above, a number of terminals exceeding the number of addresses assigned to the terminals can be connected to a single line without changing the protocol.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 3 to 6.

3 is an explanatory block diagram of the configuration of an embodiment of the present invention, FIG. 4 is an explanatory diagram of a process control table used in the embodiment, FIG. 5 is an explanatory diagram of a process queue used in the embodiment, FIG. 6 is a functional explanatory diagram of the line control layer section used in the same embodiment.

G+ (Explanation of configuration) In FIG. 3, a terminal device 100, a line control means 110
, each terminal 1201 to 120n, process control table 1
30, the line control layer section 140, and the single line 200 are as described in FIG.

In the line control means 110, a line control circuit 111 controls connection to the single line 200. Reference numeral 112 denotes an interface section which internally has a transmission buffer, a reception buffer, a semaphore function, etc. (all of which are not shown), and provides an interface to the line control layer section 140.

A line control unit 113 controls the operations of the line control circuit 111 and the interface 113 using a line control program.

In each terminal 1201 to 120n, 1211 to 12
1n is an application section of each terminal, and programs control each process such as transmission and reception executed by each terminal. 1
Reference numerals 221 to 122n denote interface units which internally have a transmission buffer, a reception buffer, a semaphore function, etc. (all of which are not shown), and provide an interface to the line control layer unit 140.

As described above, the line control means 110 and each terminal 1201 to 120n
The configurations of each of their internal parts are the same as those of the conventional ones, and their respective operations are also common.

Next, the process control table 130 is
This will be explained with reference to the figures.

As shown in FIG. 4, the process control table 130 includes (
i) Executing process pointer, (ii) Execution head process pointer 1, (iii) Execution end process pointer, (iv) Transmission PCB (Process) for each terminal.
Control Block ), (v) reception P CB for each terminal, and (vi) terminal address for each terminal.

The contents of these (i) to (vi) will be explained with reference to the process queue shown in FIG. In Figure 5, the number of terminals is 4.
An example of a process queue is shown.

(i) Executing process pointer This pointer points to the line control program (11
3) refers to the PCB of the process being serviced by (see Figure 5). Note that, as described above, the line control unit 113
The program, that is, the line control program, is as described above.
It is possible to service only one process at a time. When the line control program is not servicing any process, this pointer is cleared to zero.

(ii) First process pointer waiting for execution A process that cannot yet be serviced by the line control program is
A queue (process queue) is composed of PCBs representing each of these processes. P at the head of the process queue
This pointer points to the CB (see Figure 5).

When the process queue is null, ie, no process is attached to the process queue, this pointer is cleared to zero.

(iii) End process pointer waiting for execution Points to the PCB at the end of the process queue.

When the process queue is null, this pointer is cleared to zero.

(iv) Transmission PCB As shown in FIG. 4, the transmission PCB is composed of a next-execution process pointer and process parameters.

When the PCB containing it is connected to a process queue, the next execution waiting process point indicates the PCB connected next to this PCB. When the containing PCB is at the end of the process queue, this pointer is cleared with an all mark (F in hexadecimal).

The process parameters include parameters necessary for transmission (transmission message length, etc.).

(v) Reception PCB The reception PCB includes a next execution waiting process pointer and process parameters. The function of the former is similar to the next execution waiting process pointer of the sending PCB, and the latter includes parameters necessary for reception (received message length, etc.).

(vi) Terminal address As shown in FIG. 4, the terminal address given to each terminal is stored in the terminal address.

The line control layer section 140 will be explained in detail in the following operation description.

G2 (Description of Operation) The operation of the embodiment shown in FIG. 3 will be explained with reference to FIGS. 4 to 6. Line control means 110 and each terminal 120 to 12
Since the operation of 0n is similar to the conventional system, the description will focus on the line control layer unit 140.

FIG. 6 shows each function performed by the line control layer unit 140 in relation to other parts.

The line control layer unit 140 has the following three main functions: (1) service to each terminal 1201 to 120n;
It has 2) a process queue monitoring function, and (3) a line control program monitoring function.

The operation of the embodiment shown in FIG. 2 will be explained below, focusing on these three functions. Note that the numerals such as ■2 used in the description correspond to the same numerals shown in FIG. 6, and indicate the respective processing contents, operation contents, etc.

(1) The process of sending or receiving a service to each terminal starts when one of the terminals 1201 to 120n issues a process request to the line control layer section 140.

The service functions for each terminal are shown in the order of operation as follows.

■ Accepting process requests from each terminal.

■ Analyzes the content of the process request and detects information such as whether it is a send request or a receive request, the requesting terminal, and the length of the message.

■ Organize the PCB of the requested process and enqueue it to the process queue on the process control table 130 (see FIG. 5). Process requests generated at each terminal are enqueued to the process queue in the order in which they occur, so that process scheduling is performed in the order in which they occur.

(2) Process queue monitoring The line control layer unit 140 normally monitors (1) the state of the process queue and (2) the busy state of the line control program. Then, if there is a waiting process in the process queue and the line control program is not busy, the following operation is performed.

■ Move the PCB of the first process on the process queue to the running state.

(2) Retrieve necessary parameters from the PCB of the first process and request the line control program to execute this process.

(2) If the process is a transmission request, refer to the terminal address in the process control table 130, add an extended message header to the transmission message, and pass this transmission message to the line control program.

A series of control operations in which the line control program, that is, the transmission message received by the line control unit 113 via the interface unit 112 is transmitted from the line control circuit 111 to the single line 200, is performed in the same manner as in the prior art.

(3) Line control program monitoring The line control layer section 140 normally monitors (1) the termination status of the line control program. When the line control program completes one process, it performs the next operation.

(3-1) When the completed process is a sending process If the executing PCB on the process queue is a sending PCB,
Perform the following processing.

[Phase] Move the running PCB to the stopped state.

■ Notify the terminal corresponding to the PCB of the end of transmission.

If the PCB being executed on the process kinny is not being sent, an error occurs.

(3-2) When the completed process of the line program is a receiving process (A) The PCB being executed on the process queue is the receiving PC
If it is B, perform the following processing.

@ Deliver the received message to the terminal corresponding to the PCB using the following method. That is, the extended mensage header is checked for consistency. If they match, the extended message header is deleted and the received message is passed to the terminal at the specified address.

If they do not match, process (B) or (C) is performed.

■ Put the running PCB into a stopped state.

■ Notify the reception to the relevant terminal.

(B) PC that matches the extended message header of the received message
If B is in the waiting state, the following processing is performed.

@M Delete the extended message header and pass the received message to the terminal corresponding to this PCB.

[Phase] Delete the corresponding PCB from the process queue.

■ Notify the reception to the relevant terminal.

(C) If there is no PCB on the process queue that matches the extended message header of the received message, perform the following processing for the terminal that matches the extended message header of the received message.

[Phase] Delete the extended message header and pass the received message to the corresponding terminal.

[Phase] Notify the corresponding terminal of forced reception. In case (C), a message is sent from the host side (not shown) when no reception request has been issued from the terminal side, so forced reception is performed on the corresponding terminal.

Although one embodiment of the present invention has been described above, each structure of the present invention is not limited to the structure of the embodiment.

H [Effects of the Invention] As explained above, according to the present invention, the following effects can be obtained.

(b) Even if there is a limit to the number of addresses assigned to terminals, by expanding the message header without changing the protocol, it is possible to connect more terminals than the number of addresses assigned to terminals to a single line. I can do it.

(b) Since an interface having a common configuration can be used between the line control program and each terminal application program, these interfaces can be unified.

[Brief explanation of the drawing]

Figure 1: Detailed explanatory diagram of the present invention. Figure 2: An explanatory diagram of an example of an extended message format used in the present invention. Figure 3: Explanation of an embodiment of the present invention. Figure, Figure 4...
Figure 5: An explanatory diagram of the process controller/pull used in the same example. Figure 5: An explanatory diagram of the process queue used in the example. Figure 6: Line control layer used in the actual example. FIG. 7 is an explanatory diagram of a conventional method for connecting multiple terminals to a single line. In FIG. 1 and FIG. 3, 100...terminal device 1.110...line control means,
1201-120n...Terminal (including sub-terminal), 1
30... Process control table, 140... Line control layer section, 200... Single line. Patent Applicant: Fujitsu Co., Ltd., Me! Jin-Shikku f-Ma-lt (A) f'15 gFI l2yoyorite1ndaiattack≠lJin-shi11-Ma-lt (B) Fig. 2 Pointed blade and 41'11- For 1. Rahb-7 Chisesu weight 1st Atheka and 4th picture length rotation rJ, :M, IraHropro beggar~zu 1st figure 5 (A) (C) Juto insult l late Kira grass - Yamanashi ,. Hatchabobe Figure 7

Claims (1)

[Claims] A terminal device (10
0) is allocated and a plurality of terminals (120_1 to 120_n) are connected to the terminal device corresponding to a predetermined transmission slot in a system in which data is exchanged between the corresponding terminal device and a control device using the transmission slot. At the same time, the terminal device (100) is provided with (a) a process control table (1) in which a schedule for processing process requests generated from the plurality of terminals (120_1 to 120_n) and information necessary therefor are set;
(b) Using the process control table (130), create a schedule for processing each process requested from each terminal (120_1 to 120_n), set it in the process control table (130), and execute it. If the process to be executed is a sending process, an extension message header containing the address of the terminal that issued the transmission request is added to the transmission slot and transmitted; if the process to be executed is a receiving process, the extension message in the transmission slot is transmitted. A method for connecting a plurality of terminals to a single line, comprising: a line control layer section (140) that performs a process of distributing received messages to terminals having addresses included in the header.