A screen of a scanning type display is divided both in the horizontal and vertical directions or abscissa and ordinate directions into a relatively large number of dots, so that the screen comprises an arrangement of dots (of the total number of the relatively large number by the relatively large number) arranged in the horizontal and vertical directions. The arrangement of dots of the screen is divided into columns each having a relatively small number of dots in the horizontal or abscissa direction. Each column is identified by a corresponding ordinal number so that the same may be the abscissa information. On the other hand, each row of each column is identified by a corresponding ordinal number so that the same may be the ordinate information. Two line buffer memories are provided for storing display control information of lines which are different by a predetermined number of lines in the vertical direction. These line buffer memories are alternately controlled such that while one is in a write mode the other is in a read mode, whereby the same are alternately changed to the write mode and the read mode for each line of the horizontal scanning lines. Character information is read from a character pattern storing memory responsive to the display control information read from the other line buffer memory. A display position of the character is freely changed in the vertical direction and/or the horizontal direction on a dot-by-dot basis by controlling the read timing of the character information. A deformed character can also be displayed from the same character information by changing for each line the reading of the character information.

A terminal controller for allowing concurrent operations of a plurality of application programs, each said application program using an input/output data stream including an address information for enabling to display data on the overall screen of a terminal enables the outputs from application programs which operate concurrently to be displayed on the split screen of a single terminal linked with said terminal controller. An address conversion is carried out in the terminal controller on at least a portion of the address information in an input data stream input from a terminal and on at least a portion of the address information in an output data stream output from an application program.

An industrial control circuit includes: a first isolation circuit (22) for converting an analog signal to a low level voltage; a single-chip microprocessor SCM (23) for receiving the low level voltage from the first isolation circuit, and generating a control signal according to the low level voltage; and a second isolation circuit (24) for converting the control signal to a high level voltage. The SCM has at least thirty-two input/output (I/O) channels. Because the SCM used in the industrial control circuit has at least thirty-two I/O channels, the industrial control circuit can synchronously deal with sixteen-bit bidirectional communication.

A work station of a computer system capable of batch storing and retrieving image data separately from a usual data file system, equipped with a main processor, main processor memory and direct memory access (DMA) controller connected to a common bus, equipped with a graphic processor and window memory between the common bus and an image data bus, and equipped with a frame memory in connection with an image display unit on the image data bus, wherein the work station is further provided with an image data memory, e.g., disk unit, on the image data bus, a memory input/output controller lcoated between the image data memory and the image data bus for controlling image data transfer using a direct memory access (DMA) function, and an image data input unit and output unit connected to the memory input/output controller, so that mass image data can be transferred directly between the memory and input/output units under control of the memory input/output controller without going through the window memory.

An improved method is disclosed for providing to the operator of an interactive text processing system a displayed summary confirming the effect of requested changes to the field order in an existing file of spatially related data stored in the system prior to creation of new file. The method involves simultaneously displaying to the operator on one screen the header portions of the existing source file and the destination file and causing the data in predetermined fields of each header to be displayed in a manner which is different than the manner in which the data in the remaining fields of said headers is displayed so as to manifest to the operator similar treatment by the system of the data in both headers which is similarly displayed. The header portion of the source file is displayed such that those fields which are not to be copied into the destination file are reverse video displayed, while those fields which are to be copied to the destination file are in normal display. The header portion in the destination file is displayed such that those fields which appear in the existing file and which are to receive data from the source file are displayed in normal manner, while fields which are not to receive data from the source file are reverse video displayed. The resulting display then manifests to the operator those fields which will be copied from the source file to the destination file and provides the opportunity for the operator to confirm the correctness of the interactively entered instructions prior to actual creation of the new file.