JPS6126163A - High speed data transfer system - Google Patents

Abstract

PURPOSE:To attain data transfer without lack of data even if the input interval of the data is shorter than a buffer replacing time, by forming an automatic buffer replacing mechanism in double-buffering type data transfer. CONSTITUTION:In the double buffering type data transfer, the same number of commands for inputting data corresponding to the capacity of buffers alternately to two buffers 1-3, 1-4 as the number of inputs of all transfer data are formed and stored in the main memory 1-2. When the address of the initial command is specified and an input channel is started, the input channel reads out the succeeding commands automatically to execute the processing. These buffers are switched by previously storing a buffer 1-3 sending command and a buffer 1-4 sending command in the main memory device 1-2 and specifying the sending com mand in accordance with the even or odd number of the counting value of command interruptions. Even if the data input interval is shorter than the buffer replacing time, the data can be transferred without an lack.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides a high-speed data transfer method, more specifically, a method for inputting digital data at a constant speed, importing it into a computer in real time via an input channel, and transmitting the data via an output channel. In particular, the data input interval (the time from the completion of inputting one bit signal to the start of inputting the next bit signal) is the time required for buffer replacement. The present invention relates to a transfer method suitable for a case where the time is shorter than the time required for transfer.

[Background of the invention]

Digital data is input at a constant rate, captured in real time via the input channel, and captured in °C via the output channel.
As a real-time data transfer method for sending data to an output device in real time, a conventional double buffering method has been common.

Controlling data transfer Two storage areas of a fixed capacity are provided in the main memory of the computer (these are called buffers).The processing unit of the computer transfers a specified amount of data to one buffer for each input channel. At the same time, it instructs the output channel to send the specified amount of data from the other buffer.When the above-mentioned capture processing of the input channel and the above-mentioned transmission processing of the output channel are completed, the processing device The buffer used for sending data is replaced with the buffer used for sending data, and the buffer used for sending data is replaced with one used for receiving data.The same process is then repeated.This is a method for performing data import processing and data sending processing at the same time.Specifically, the following Do it like this.

(1) Two storage areas of a certain capacity are provided in the main storage of the computer. These are called buffer 1 and buffer 2. Also,
The capacity of these buffers is called buffer capacity.

(2) The processing unit of the computer issues an instruction to the input channel to take in data corresponding to the buffer capacity into buffer 1. Upon receiving this command, the input channel starts taking in data from buffer 1.

(3) When the processing device receives a data acquisition completion signal (referred to as an input interrupt) from the input channel, it performs an error check on the acquisition process.

(4) After this, issue an instruction to the input channel to take in data corresponding to the buffer capacity into buffer 2. At the same time, a command is issued to the output channel to send the data in buffer 1 to the output device. In response to these commands, the input channel starts taking in data from the buffer, and the output channel starts sending out data from buffer 1.

(5) When the processing device receives an input interrupt from the input channel, it performs an error check on the capture process.

(6) After this, a command is issued to the input channel to take in data corresponding to the buffer capacity into buffer 1, and at the same time, a command is issued to the output channel to send the data in buffer 2 to the output device. These instructions cause the input channel to start taking in data from buffer 1, and the output channel to start sending out data from buffer 2. Until all data to be transferred is completed (3) to (6)
Repeat the process.

In the above method, after the input channel completes data capture for the buffer capacity, the processing unit switches the capture and output buffers and issues a capture command to the input channel again (buffer replacement). time), processing is stopped. If this stop period exceeds the data input interval (time from completion of input of one bit signal to start of input of the next bit signal), loss of captured data will occur.

[Purpose of the invention]

An object of the present invention is to change the input and output buffers without stopping input channel input processing when performing real-time transfer processing of digital data using a double buffering method. An object of the present invention is to provide a transfer method capable of transferring data without loss even when the interval is shorter than the buffer replacement time of a computer.

[Summary of the invention]

In the present invention, data is transferred using a cooking method in order to achieve the above object.

(1) Provide the following automatic replacement buffer function for the input channel. In response to one instruction from the processing device, the process of taking in a specified amount of data into one buffer and the process of taking in a specified amount of data into the other buffer are performed alternately a specified number of times.

(2) The processing device is provided with the following output channel activation function. It detects that the input channel has completed loading a specified amount of data into one buffer, and instructs the output channel to send out the data from the buffer that has completed loading.

As described above, the input channel takes in data while changing the buffer every fixed amount until all the data to be transferred is completed. During this time, the input channel does not stop the acquisition process. Further, the output channel executes this instruction each time it receives an instruction from the processing device to send data from the specified buffer.

Therefore, according to the present invention, the buffers for capture and output can be exchanged without stopping the capture process of the input channel.

[Embodiments of the invention]

Hereinafter, an embodiment in which the present invention is applied to a satellite image data receiving system will be described.

FIG. 1 shows the overall configuration of a satellite image data receiving system. This data receiving system performs the following processing.

Satellite image data is received by a receiver 3 and an antenna 2, demodulated into a serial digital signal, and then converted into a parallel digital signal by a synchronizer 4.

The parallel digital signal (data amount: approximately 60 megawords (120 megabytes), input interval: 15.2 microseconds) is input to the computer 1 via the input channel 5, and is sent to the magnetic disk device 7 via the output channel 6. Send.

In the receiving system described above, parallel digital signal transfer processing is performed in two buffers 1 and 1 in the main storage device 1-2 of the computer.
-3.1-4 (Capacity: 1.2 kilowords each,
This is done using a double buffering method.

In this case, if transfer processing is performed using the conventional double buffering method, it will take 30 microseconds for buffer replacement. Since the input interval of the captured data is 15.2 microseconds, the captured data is lost.

Therefore, according to the high-speed data transfer processing method of the present invention, data transfer processing is performed as follows.

(1) Realization of data import and import buffer alternation processing: As shown below, the command to import data equivalent to the buffer capacity into two buffers (BUFI, BUF2) alternately is executed.
Create as many files as you need to capture all the transfer data, and store them in the main memory.

READ BUFI 12000 1(
command), (data import arrowhead (number of data words), (next command available) READ, BtJF2 .12000
．． 1Ljl READ, BUFI, 12000
, IREAD, BUF2. 12600
．． 0 (No next command) After storing the above commands, when the address of the first command is specified and the input channel is activated, the input channel automatically reads subsequent commands and executes the processing.

(2) Realization of data transmission and transmission buffer replacement processing: Do it as follows.

(a) A command to send the buffer capacity's worth of data from buffer 1 to the magnetic disk device (buffer send command) and a command to send the buffer capacity's worth of data from buffer 2 to the magnetic disk device (buffer 2 send command).
Store it in the main memory in advance.

(b) Create a program that performs the following processing.

1) It is activated by the execution end signal (command interrupt) of one command from the input channel, and counts the number of command interrupts from the time when the capture process is started.

++) If the count value of the above command interrupt is an odd number, specify the buffer 1 send command and start the output channel. If the count value is an even number, specify the buffer 2 send command and start the output channel.

As a result of the above, command interrupt from the input channel causes
Activate the output channel and send data alternately from the two buffers to the magnetic disk.

〔Effect of the invention〕

According to the present invention, when transferring data in real time using the digital data double buffering method, buffers for taking in and sending out can be exchanged without stopping the taking process of the input channel. Therefore, even if the data input interval is shorter than the buffer replacement time, data can be transferred without loss.

[Brief explanation of drawings]

FIG. 1 shows the overall configuration of a satellite imaging system to which a high-speed data transfer method according to the present invention is applied. 1... Computer, 1-2... Main storage device, 1-3.1
-4... Buffer, 2... Antenna, 3... Receiver, 4... Synchronizer, - Input channel, 6...
Output channel, 7...disk device.

Claims (1)

[Claims] In order to realize a data transfer system that inputs digital data at a constant speed, inputs it into a computer in real time through an input channel, and outputs it in real time through an output channel, a computer processing device and an input device are used to control the transfer process. , two storage areas (called buffers) provided in the computer's main memory to temporarily store data, and an input channel that reads data from the input device to the designated buffer according to instructions from the processing device. , in a data transfer facility consisting of an output device and an output channel that sends a specified amount of data from a specified buffer to the output device according to instructions from a processing device; An automatic buffer switching function is provided, which alternately executes the process of importing a specified amount of data into the other buffer and the process of importing a specified amount of data into the other buffer for a specified number of times. A high-speed data transfer method that enables switching of input channels without stopping the input channel acquisition process.