DE2233452A1 - CONTROL DEVICE FOR DATA TERMINAL DEVICES - Google Patents

Description

Applicant's file number: Docket FR 971 012

Control device for data terminals

The invention relates to data terminals or terminals that are connected to a central data processing system and a control unit for controlling a number of such terminals.

Modern data transmission systems generally use a data processing system or its central unit for control the transmission of messages between the often very numerous and far apart terminals. The transferred Information circulating in the transmission lines, is transmitted by consecutively transmitted pulses of one or more amplitudes whose grouping or combinations denote the Message content defined.

It is obvious that this is the case with a data transmission system Size is advantageous to connect a large number of terminals. These terminals are connected to the central processing unit connected. The control unit is used to group the individual messages and to transmit them Messages to the central unit.

FR 971 012

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In systems of this type, the message can be sent to an outside party Terminal can be entered with the help of a keyboard for storage in a central processing unit or from query the central unit there and obtain the required information. For this purpose, the message is sent via a Keyboard entered and at the same time automatically made visible on a screen of a cathode ray tube. if the message has been entered in full, it can be checked for errors on the screen. A send button will appear pressed, which causes the message to be sent to the central unit for further processing. If required, the central unit can be made to give an answer, which is also visible on the cathode ray tube is made.

In some applications of such a system there is the one sent to or received by the central unit Message from a fixed format and changeable data. In this case it is important that the characters that the different Represent types of data that appear in the areas to which they are associated.

In general, fixed data and the areas assigned to them are stored in the memory of a central unit, from where they can be called up by a terminal when they are needed there. In this case it is useful to have a Provide area outside the fixed form, which allows a dialogue with the central unit, while at the same time the default form remains unchanged because it is to be used for several different processes. aside from that if the operator cannot respond immediately to a request from the central unit, this is an expensive one Loss of time since the terminal is permanently switched on during the entire search process.

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The object of the invention is therefore to provide means for storing fixed data forms in a control unit for terminals to be provided, which are always available, so that the operating personnel at the terminal station can communicate with each other regardless of this with the central unit. The arrangement should preferably be such that in the control unit a certain number of lines can be temporarily stored while subsequent operations are performed will. Above all, the control unit should be constructed in such a way that the central unit sends information to the terminal can be transferred while an operation is being carried out at the terminal without interrupting it. For this purpose, according to the invention, a separate memory is provided with a corresponding number of memory blocks the number of terminals. Each memory block corresponding to a particular terminal is divided into four parts, the are used for receiving, regenerating, printing and recording messages.

The invention will now be described in more detail using an exemplary embodiment in conjunction with the accompanying drawings. It shows

Fig.l schematically a control unit according to the invention, which is connected to a central unit;

Fig.2 schematically shows the special memory and the associated Circuits and

Fig.3 schematically shows the special memory.

Fig.l shows an embodiment of a control unit for terminals, via a communication line, for example, a telephone line with a central unit of a

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ORlGINAL. INSPECTED

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-A- data processing system is connected.

The control unit 1 essentially consists of the basic unit 2, a read-only memory 3, a special core memory, which is to be called bridging memory 4 in the following, a transmission adapter 5 and the terminal adapters 6.

The basic unit 2 contains an arithmetic and logical unit, RAM and registers, as well as the main clock circuit. The read-only memory 3 contains the microprogram that the Controls the transmission method and the operations with the information stored in the bridging memory 4 or data should be carried out.

The bridging memory 4 allows the storage of data, which affect the operation of each of the connected terminals and is also used as a regeneration memory for the Data display devices used. The adapter 5 contains the registers which take in data from the line via a modem 7 and transmit data to the line. The terminal adapter 6 are used Control of the data transmission between the base unit 2 and the terminals, the data display devices, such as cathode ray tubes, and, if necessary, can also be equipped with keyboards or printers. If data display devices are used each adapter 6 includes a display control unit and a display adapter.

The main memory and the registers of the basic unit 2 contain intermediate registers, a buffer memory and a general purpose register. The buffers allow the storage of Data and represent a work area for the arithmetic unallogical unit. A certain number of registers is assigned to each terminal adapter. The buffer storage is used for storing the current addresses of the bridging memory 4. In the embodiment described here, the control

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unit control four terminals, each of which has a data display terminal, has a keyboard and a printer.

FIG. 2 schematically shows the bridging memory 4 from FIG with the associated circuits for the transmission of data between the base unit 2, the bridging memory 4 and the data display devices, keyboards and printers.

The bridging memory 4 is preferably a core memory, can of course, however, be implemented in any other desired modern storage technology. Access to this memory takes place in the usual way. The bridging memory 4 is divided into four blocks of four buffer memories each, with each block having a specific data terminal assigned.

The bridging memory 4 has four output registers 9 and four input registers 10 connected to the base unit 2.

The flow of data between the memory 4 and the base unit 2 essentially comprises three different operations. Registered mail in memory, read memory and transfer from one memory position to another memory position. the The last operation consists of a read process followed by a write process.

In a write process, the data coming from the arithmetic and logic unit are saved by the microprogram in the output register 9 loaded. The registers 9 thus contain the memory address in which the data are to be stored, the data itself and a write bit. The appropriate logical Circuits check the registers 9 and then transfer the data to the memory 4.

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During the reading process, registers 9 are loaded by the microprogram and contain the memory address from which the data is taken should be and a hit book. The at the affected Address read out data are loaded in the middle of the logic circuit in the input register LC). The content of the Register 10 is then available for the arithmetic and logic unit.

When transferring from one storage location to another, the reading process - as described above - carried out and the faort to be transmitted is loaded into the register IO and then transferred to register 9 with the new address under microprogram control. Then the contents of the register 9 are again supplied to the memory 4.

To display the data in a data display device, the content a buffer memory of the memory 4, which serves as a regeneration memory, continuously by clock circuits 14 checked that the consecutive addresses of all of the positions generate in the regeneration memory. The content of these successive positions is stored in a read-only memory 12 which represents the character generator. The display is obtained by converting the series of the video registers 13 supplied pulses, as well as by horizontal 'and vertical clock pulses. These clock pulses also come from the clock pulse circuits for the visual display 14. When operating via the keyboard, the registers 15 are used to determine which contacts the keyboard are closed when pressed. The content of the register 15 is read out by the microprogram and loaded into the output register with the corresponding memory addresses.

For printing, the working registers 16 are loaded under the control of the microprogram from the deJ: arithmetic Uxid logical unit. They serve you ..-- EL-At L-Gfiajnete des Drucker ;; v

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ORIGINAL INSPECTED

actuate.

3 shows schematically the arrangement of the bridging memory 4 in Fig.l and 2. The bridging memory 4 consists of four Blocks of four buffer memories 17, 18, 19 and 20. In the embodiment described here, each terminal becomes a block allocated from four buffers. Each terminal contains a data display device with a cathode ray tube 21, a keyboard 22 and a printer 23.

Therefore, each block consists essentially of a reception buffer memory 17, a regeneration buffer memory 18, one Printer buffer memory 19 and a holding buffer memory 20. The receive buffer memory 17 stores the data coming from the central processing unit before they are transmitted to the regeneration buffer memory 18, holding buffer memory 20 or printer buffer memory 19 according to the data format. The regeneration buffer memory serves as a memory for the data display device Cathode ray tube 21. The data stored in this buffer memory are processed by associated electronic circuits read out continuously and displayed on the cathode ray tube 21. If individual keys of the keyboard 22 are pressed, then these characters are transmitted to the regeneration buffer and displayed immediately on the cathode ray tube 21. The printer buffer 19 delivers through the printer

23 the printout of information displayed on the cathode ray tube 21. For this purpose there is a print button

24 provided. Once the data from the regeneration buffer after the printer buffer has been transferred the terminal is immediately available again for the operating personnel while the Ilmessage is being printed out.

The printer buffer can also be controlled by the central unit by transmitting a special character, while the operator of the terminal presses the keyboard. In

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In this case, this message is transferred to the printer buffer immediately after the transmission has ended. The holding buffer 20 can be loaded from the receiver buffer memory 17 or from the regeneration buffer memory 18 with the aid of the key 25 will. Therefore, the holding buffer memory 20 can by the central processing unit store transmitted messages or selected lines of characters displayed on the cathode ray tube. The contents of the holding buffer 20 can also with the help of key 26 or by the central control unit with the help of a special symbol in the regeneration buffer memory 18 are transferred.

The circulation of data between these different buffers will now be described in detail. For a better understanding of the description it seems necessary to define certain terms in more detail. A "forerunner" is a specific, well-known character that appears on the Cathode ray tube is displayed, which underlines the position on the screen where the next to be displayed Characters will appear. This is controlled by the microprogram.

Accessible positions are those in which characters can be displayed. All positions are for the central unit accessible. Only the unprotected areas are accessible to the operating personnel.

Protected characters are stored in the regeneration buffer by the central unit masked so that the operator cannot enter characters there. In the ones described here Embodiments are these characters of special characters which define a protected area or a mask.

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All functions of the control unit are stored in the read-only memory 3 (Fig.l) stored microprogram controlled, which results in a high degree of flexibility for the terminals.

Due to the fact that at a certain point in time a terminal can prepare a message, for example, a Send a message to the central unit or receive it in response to a request to the central unit, it is necessary to distinguish between different operating conditions. To enter, press Keys of the keyboard selected characters in the regeneration memory stored in the forerunner position *. In the transmission waiting position the operator has finished his message and the data display device waits for a request from the central unit.

A call signal sequence is used by the central unit for the transmission recorded and then transmitted the message to the central unit. When receiving, one of the central unit incoming message stored in the regeneration memory.

The various functions possible at a terminal should will now be examined in detail.

Keyboard on display device,
Data display device to the transmission line, data display device to printer,
Data display device on holding memory,
Holding memory on the data display device,
Line to data display device,
Line to holding buffer and
Line to printer.

Function keyboard on data display device

If a keyboard is available, data can be stored in the regenerative

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FR 971 012

tion buffer memory and these data appear then immediately on the screen of the data display device, as well as the keys for the individual characters depressed will. The forerunner moves - controlled by the microprogram - by one position each time a new one Character is stored in the regeneration buffer memory. When the forerunner meets a protective symbol that marks the beginning indicates a protected area, it continues to run under the control of the microprogram until it opens for another Sign that indicates the end of this protected area and stops at the display position that points to this This is followed by a character indicating the end of the protected area.

Function of the data display device on the line

When an interrogation is received from the central processing unit, the data stored in the regeneration buffer memory are used sent over the data transmission line. The content of the transmitted message depends on the position of the first in the Regeneration buffer memory from stored characters. The address of the first character can be determined by the microprogram. Starting from the first position on the screen, the microprogram determines the position of the first character stored in the regeneration buffer with respect to the first protection character.

If the first symbol shown is before the first protective symbol, then the message begins with the first displayed character. The end of the message depends on the position of the forerunner.

If the precursor is before the first protection symbol, the message ends with the position of the precursor.

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Therefore, the screen can be divided into two parts. A lower part contains, through sent by the central unit, Protected areas formed from fixed data and variable data that can be entered by the operator. The upper part of the screen is free and can be used by the operator to request information from the central unit and by the Central unit can be used to answer these inquiries without affecting the fixed and variable data of the lower Part of the screen are influenced and accordingly would have to be sent again.

Are areas protected by the microprogram in front of the forerunner position determined, then the message ends at the last screen position, unless the predecessor is not encountered before this position. In this case the transfer jumps from the regeneration buffer to the first screen position and stops in the previous position.

If protected areas are detected before the first character is stored in the regeneration buffer, then the message begins with the first character representing the end of the protected area and usually ends at the last screen position. This allows the operator to enter his message and make corrections without having to Must move the forerunner at the end of the message. Becomes the end of a protected area while the first is being scanned character in the last display position of the Forerunner not found, the transfer jumps from that Regeneration buffer in the first screen position and so on until the forerunner is reached.

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- 12 Function of the data display device on the printer

The _s is a locally restricted mode of operation which is used to print out the data displayed on the cathode ray tube. This operation is carried out when data is transferred from the keyboard to the regeneration buffer memory or when data has been received from the central processing unit via the reception buffer memory. To print the key 24 (Fig. 3) is pressed and the keyboard is locked. The contents of the regeneration buffer are transferred to the printer buffer, provided that it is free. When the transfer is finished, the keyboard is unlocked and the terminal is available again while the contents of the printer buffer are being printed out.

If the printer buffer memory is not available, the keyboard remains locked and the terminal has to go to the end wait for the printing process before the contents of the regeneration buffer are transferred to the printer buffer, can.

Puncture visual display device on holding buffer

This is also a localized operation that allows the operator to select and save a particular row displayed on the cathode ray tube. This operation is carried out with the help of the precursor. The operator sets the forerunner to the selected line using the appropriate keys and presses the selection test (switch 25 in FIG. 3). If the holding buffer memory is not full or if it does not contain any data transferred from the central processing unit, then the selected line is transferred from the regeneration buffer memory to the holding buffer memory.

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Function holding buffer memory on the data display device

Again, this is a localized surgery that does it allows the operator to redisplay all previously selected lines on the screen. To perform this ope- ' ration, the operator presses key 26 in Fig.3. The contents of the holding buffer are then stored in the regeneration buffer in which all previously stored data is deleted. The selected lines then appear in the Order on the screen in which they were stored in the holding buffer. When the holding buffer contains lines selected by the operator, then the content of this holding buffer memory is retained by the carryover after the Regeneration buffer deleted. Contains the holding buffer data transmitted from the central processing unit, then the contents of the holding buffer are saved by the transmission to the Regeneration buffer memory not deleted. In this case, only the central processing unit can store the contents of the holding buffer delete by sending a special character.

In addition, the central processing unit can store the contents of the holding buffer by sending a special character into the regeneration buffer memory transfer.

Function line to data display device

If data has been properly received in the receive buffer, then an addressing operation of the regeneration buffer transmits this data in the regeneration buffer and makes them simultaneously on the cathode ray tube in the Forerunner position visible. The central unit can then use special characters to update the precursor at the beginning of a message set the forerunner to every screen position.

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- 14 Function line to holding buffer memory

When data is properly recorded in the receive buffer, then causes a positive addressing of the holding buffer memory the transfer of the data to this memory.

Then the data contained in the receive buffer memory can either can be transferred to the regeneration buffer memory by the central unit or by the operator. The central unit this transfer can be done by sending a special character either to the holding buffer or to the regeneration buffer initiate. This character can be transmitted alone or as the last character in a message. In the latter case, the message sent out in this way is transferred directly to the regeneration buffer memory.

If the holding buffer contains lines selected by the operator, then one will be initiated by the central processing unit Addressing sequence of the holding buffer rejected. However, the central unit can overcome this block by that they first send a special character to the regeneration buffer releases, which causes the transfer of the contents of the holding buffer memory to the regeneration buffer memory and clears the contents of the holding buffer.

Function line to printer buffer

When data has been correctly recorded in the receive buffer, causes a positive addressing of the printer buffer memory the transfer of this data to this memory and the message is printed out. When the printer buffer contains data that has not yet been printed out, an addressing process is performed of the printer buffer memory is rejected by the central unit until the printer buffer memory after printing the message saved in it is available again

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ORIGINAL INSPEGTiO

stands.

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ORIGINAL INSPECTED

Claims (1)

223 Patent claims Control unit for data terminals with an arithmetic and logical unit, a main memory, a microprogram read-only memory with an adapter for connecting the control unit to the central unit and a number of terminal adapters, characterized in that a bridging memory (4) is provided which is inserted into one of the Number of terminals is divided into the corresponding number of memory blocks, and that each of these memory blocks in turn is subdivided into memory areas assigned to certain functions. Control unit according to claim 1, characterized in that that in the bridging memory each memory block has a receive buffer memory (17), a regeneration buffer memory (18), a printer buffer memory (19) and a holding buffer memory (20). Control unit according to claim 1 or 2, characterized in that parts of the buffer memory are partially covered by one of Mask transmitted to the central unit against occupancy and deletion of the information stored there by the data terminals are locked. 309808/1 U 7 FR 971 012 λ- Blank page