JPS5815991B2 - Mailbox communication method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a mailbox communication system.

Conventionally, in data exchange networks with data storage functions,
The exchange network lends a part of its storage device to the contract terminal as a mailbox, and this mailbox stores messages sent from unspecified or specific terminals to the mailbox contract terminal, and the mailbox contract terminal A mailbox communication system has been proposed in which messages stored in a mailbox are read by issuing requests to the mailbox at any time.

In such a mailbox communication system, one of the major technical issues is how to effectively use a mailbox with a limited storage capacity.

To explain a conventional example of a mailbox communication method using drawings, FIG. 1 is a block diagram showing an outline of a system for embodying the conventional method, and 1 in the figure is a mailbox, and 2 is a mailbox. 3 is a mailbox write address storage circuit, 4 is a mailbox read address storage circuit, 5 is an address difference calculation circuit, 6 is a comparison circuit, and 7 is an AND circuit.

The difference calculation circuit 5 subtracts the content of the read address storage circuit 4 from the content of the write address storage circuit 3 to calculate the amount of stored messages, and further subtracts this calculated value from the contracted memory size to determine the amount of memory. The remaining size is output to the comparison circuit 6.

More detailed operation of the above system will be explained with reference to the signal sequence shown in FIG. The mailbox write message length information S3 and the comparison request signal S4 in the signal are transmitted to the mailbox management section 2.

The comparison circuit 6 compares the write message length information S3 with the remaining memory size added from the address difference calculation circuit 5, and adds the comparison result to one input terminal of the AND circuit 7.

This comparison result is sent to the AND circuit 7 by a comparison request signal S.
4 is ANDed and sent to the write terminal TA as a signal indicating whether writing is possible or not.

When the signal indicates that writing is possible, the writing terminal TA sends the message C and the write request report S1 to the exchange, and the exchange that receives this sends the message C and the write instruction information W (write address (including) to mailbox 1.

When the writing of the message is completed, the exchange sends a writing completion signal d to the writing terminal TA, and terminates the communication with a disconnection signal e and a disconnection confirmation signal f, as shown in FIG.

On the other hand, when the exchange receives the read request signal g issued from the mailbox contract terminal TB at any time, it checks the status of the designated mailbox and reads the terminal.

A read permission signal is sent to the TB, and a read request signal S2 is sent to the management section 2.

The message stored in the mailbox is read out according to the read instruction information R (including the read address) and sent as a message 1 to the terminal TB.

When the reading of the telegram is completed, the exchange terminates the communication with a disconnection signal and a disconnection confirmation signal k, as shown in FIG.

In the conventional method described above, since the size of the mailbox is limited, there is a high possibility that the mailbox will become full in a short time depending on the size of the message being written and the frequency of writing. The drawback is that the serviceability seen from the box writing terminal is poor.

Furthermore, the above-mentioned conventional system also has the disadvantage that, from the perspective of the contract terminal, the burden on the terminal operator for reading and outputting mailboxes increases.

This invention was made in view of the above-mentioned drawbacks of the conventional system, and its purpose is to provide a mailbox communication system that improves serviceability from the point of view of the writing terminal and reduces the burden on the terminal operator at the contract/terminal. Our goal is to provide the following.

Hereinafter, the details of the present invention will be explained with reference to examples.

FIG. 3 is a block diagram showing an overview of a system used to embody an embodiment of the communication method according to the present invention. 2 represents the same circuit as described with respect to the figure.

8 is a message automatic transmission value accumulation circuit, 9 is an automatic transmission calculation circuit,
10 is an AND circuit.

FIG. 4 is a diagram showing a signal sequence for explaining the operation of the system in FIG. 3, in which signals given the same reference numerals as in FIG. show.

The mailbox writing part of the signal sequence in FIG. 4 is the same as the conventional example shown in FIG.

In the storage circuit 8 shown in FIG. 3, the allowable value γ of the amount of accumulated messages normalized by the contract memory size of the mailbox is accumulated as the automatic message sending value, and this allowable value γ is one of the input terminals of the arithmetic circuit 9. added to.

The contract memory size α and the remaining memory size β output from the address difference calculation circuit 5, the write message length information S3, and the logic output of the AND circuit 7 are applied to other input terminals of the arithmetic circuit 9, respectively.

; Based on these inputs, the arithmetic circuit 9 calculates (β+b・S
3) Compare the magnitude of /α and γ, and get (β+b・S3)
When /α≧γ, a logic “1” is output to one input terminal of the AND circuit 10.

This logical output is ANDed with the comparison request signal S4 in the AND circuit 10, and is sent from the exchange to the contract terminal as a paging signal l for automatic message sending.

Thereafter, upon receiving the response signal m transmitted from the contract terminal in response to the above-mentioned paging signal l, the exchange sends a read signal S2 to the management section and reads out the message according to the read/instruction information R. i is sent to contract terminal TB.

In the above embodiment, when the message usage rate exceeds the value specified by the contract terminal, that is, when the accumulated message amount normalized by the contract memory size exceeds the allowable value γ specified in advance by the contract terminal, the mailbox However, in place of the message usage rate mentioned above, the allowable value of the number of accumulated messages is set in the automatic message sending value accumulation circuit 8, and the management unit 2 is provided with a function to count the number of accumulated messages. It is also possible to have a system in which the stored messages are automatically sent to the contract terminal when the number of messages accumulated in the mailbox exceeds a predetermined value.

As explained above, according to the present invention, even if the size of the message written to the mailbox and the writing frequency change, the possibility that the mailbox becomes full is reduced, and serviceability from the perspective of the writing terminal is improved. In addition, there is an advantage that the burden on the operator of the contract terminal is significantly reduced.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a system for embodying a conventional mailbox communication method, Fig. 2 is a signal sequence for explaining the operation of the system shown in Fig. 1, and Fig. 3 is a mailbox communication system according to the present invention. FIG. 4 is a block diagram of a system for embodying the method, and is a signal sequence for explaining the operation of the system of FIG. 3. 1...Mailbox, 2...Mailbox management section, 3...Mailbox write address storage circuit, 4...Mailbox read address storage circuit, 5... Address difference calculation circuit, 6... Comparison circuit, 7, 10...
AND circuit, 8... Automatic message transmission value accumulation circuit,
9... Automatic sending calculation circuit.

Claims (1)

[Claims] 1. In a mailbox communication system in which a switching network with a data storage function lends a storage area for storing messages sent from a terminal to a subscribed terminal as a mailbox, the mailbox is Or when the number of messages exceeds the value specified by the contract terminal,
A mailbox communication method characterized in that a message stored in the mailbox is sent to the contract terminal.