JPS5955528A - Data transfer system - Google Patents

Abstract

PURPOSE:To simplify the processing as well as to decrease the number of instructions between host communication controllers, by providing a means which informs the length of each reception data divided into one or plural blocks. CONSTITUTION:A reception data length holding means, etc. is provided to inform the length of each reception data divided into one or plural blocks. For instance, when the data is received at a host 1 from a terminal 5, the host 1 delivers a read instruction to a communication controller 2. Then the controller 2 performs transmission/reception via a transfer buffer 9, and a data length register 8 holds temporarily the count value of the length of the data which is transferred by a read command and then transfers the count value to the host 1 at the start of the data transfer. Then the data is transferred to a reception data buffer 6 of the host 1 from the buffer 9 via a data address register 10, etc. and in order of address rising.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to the length of received data in a communication control device and the transfer method of that data, and in particular, unlike high-level procedures, there is no delimiter in the data to indicate the end of the data. The present invention relates to a data transfer method that makes it possible to notify the host of the effective data length in a communication method where the effective data length cannot be determined just by the host checking the received data buffer.

[Conventional technology and problems]

Conventionally, the method for notifying the received data length as data from the communication control device to the host includes: ■ At the beginning of the buffer in which the received data is stored,
Store the data length.

■ Next READ of the area where received data is stored
The data length is stored in the area indicated by the command.

There are two methods, but in the former, the data length, which can only be known after the reception processing of the received data of each block is completed, must be stored before the data. This requires operations such as returning the transfer address to the address indicated by the command, which has the disadvantage of complicating the process. On the other hand, the latter has the disadvantage that two READ commands are required to receive one data, which places a load on the communication control device and channel.

[Object and structure of the invention]

The purpose of the present invention is to improve all of the drawbacks of the conventional method described above, and to include the transfer data, the data length, and the data length in one READ command as one of the data, so that the received data in the host indicated by the command is By storing data addresses in the buffer in ascending order from the smallest number, processing can be simplified, in particular, the (n-1)th data length and the nth received data can be processed with the nth READ command. This reduces the number of interactions between the host and the communication control device.

Original F! For this purpose, A is a communication control device that operates based on commands from the host, and is configured to receive data received from a line and is divided into a series or a plurality of blocks, and to notify the host of the data length of each piece of data. It is equipped with a data length holding means and receives a READ command from the host to transfer the nth received data to the receive data buffer provided in the host.
n, the data length of the (n-1)th received data is transferred from the received data length holding means and stored first in the data storage address of the memory indicated by the ggEAD#n command; Thereafter, by sequentially storing the n-th received data in the address following the data storage address, the received data from the data line and its data length are transferred to the post.

[Practice of the invention ρυ]

The present invention will be explained below with reference to Examples.

FIG. 1 is a block diagram of the data communication (M system) of the present invention MMFio. In the figure, 1 is a host, 2 is a communication control device, 3 and 4 are modems, 5 is a terminal, 6 is a receiver 7 is a data buffer, 8 is a data length register, 9 is a transfer buffer, and 1o is a delta address register for the reception data buffer 6.

When receiving data from the terminal 5, the host 1 issues a REAI) command to the communication control device M2. 91 (7J
The size of the data transferred by the RE A D command is arbitrary within a certain upper limit, and is sent and received in the communication control device 2 via the transfer buffer 9. Data length register 8
temporarily holds a count value of the length of data transferred in one READ command, then he < RE A
The first data transfer with the D command is transferred to the host 1. Data transfer processing from the transfer buffer 9 to the reception data buffer 6 of the host 1 is performed only in ascending order of addresses, and is managed by the data address register 1o. After the data address register lo is set with a start address by a READ command from the host, data storage addresses can be generated in ascending order, so that a simple control mechanism can be used.

FIG. 2 shows the contents of the receive delta buffer 6 in sequential RE A D commands.

FIG. 3 is an explanatory diagram of the operation of storing received data and data length in the received data buffer 6 for each READ command. ○ FIG. 4 is a flowchart of the control operation performed by the control unit 7 for one READ command. It is a diagram.

The operation of the embodiment will be described below with reference to FIGS. 2 to 4.

In response to the first RE A D command (#1) issued by the host, the communication control device stores a dummy character in the data length storage area of the received data patterner 6 because there is no data immediately before.

Thereafter, the received data #l is stored in ascending order until the end, and even if there is a surplus in the storage area, no particular transfer process is performed on that area. When the completion of transfer of one complete received data #1 is detected, the data length is stored in the data length register 8, and the READ command (#1) is terminated. The host sends a new RE to continue receiving the next data.
Issue AD command (#2). With this READ command -
, communication control device t;1, first transfers the data length of the previous received data #1 stored in the data length register 8 to the start address of the data area indicated by the command, and then transfers the data length of the previously received data #2. Forward. 1 complete received data #
When the completion of transfer 2 is detected, the data length is recorded and the above process is repeated. Next, when the last data is received, the processing is as follows: [line 7:/2'1-)f. That is, the R E A I that transferred the last received data
) command followed by the R E A D command.
,J, Since there is no received data to be transferred, only the data length of the immediately previous received data is transferred. In this way, in the present invention, n pieces of received data are transferred to (n11 pieces of RE A
It can be processed using the D command.

〔Effect of the invention〕

According to the present invention, since there is no need for address subtraction processing in executing the RE A D command, it can be carried out even by a device with a simple configuration that can only transfer data in ascending order of addresses, and the received data The data and data length can be notified to the host without increasing the number of 1ζEAD commands for data length transfer.In addition, the interference between the communication control device and the host is reduced, reducing the concentration of load. This can be avoided and an efficient system can be built.

It is obvious that the data length used in the present invention does not have to be the data length itself, and may be information that uniquely corresponds to the data length. Furthermore, when transferring the data length, it is also possible to transfer additional information other than the data length.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of the system according to the present invention, and Figure 2 is the RE
Figure 3 is an explanatory diagram of the function of the AD command, Figure 3 is an explanatory diagram of the storage operation of data and data length, and Figure 4 is an explanation diagram of the function of the AD command.
A flowchart of the operations executed regarding the EAD command. In the figure, 1 is the host, 2 is the communication control device, 3 and 4 are the modem, 5 is the terminal, 6 is the receive data buffer, and 7t control 911
1 capital, 8 data length register, 9 transfer pattern, 10
represents the data address register. Patent applicant Fujitsu Ltd. Representative Patent Attorney Fumihiro Hase (1 other person) -1: Figure 1 Figure 2

Claims (1)

[Claims] A communication control device that operates based on instructions from a host, comprising a received data length holding means for notifying the host of the data length of each piece of received data received from a line and divided into a series or a plurality of blocks, RE the READ command from the host to transfer the nth received data to the receive data buffer provided in the host.
When AD#n, the data length of the (n-1)th received data is transferred from the received data length holding means to the data storage address of the memory indicated by the RE A D #n command. A data transfer characterized in that received data from a data line and its data length are transferred to a host by first storing the received data and then sequentially storing the nth received data in an address following the data storage address. method.