Abstract: A multiple window display system is provided for displaying data from different applications in a multi-tasking environment. The display system includes plural screen buffers (12.sub.l to 12.sub.n) for storing character codes and attribute codes of data which may be displayed on the display screen. Task selection means (26) selectively couples the output of a single selected one of the plural screen buffers to the character generator (16) and attribute logic (18) at any given time. Address modification means (20.sub.l to 20.sub.n, 22.sub.l to 22.sub.n) permits changes to be made in the display windows. The software driver includes screen control blocks (32), window control blocks (34), presentation space control blocks (36), presentation spaces (38), and a screen matrix (40) in system memory. The presentation spaces (38) receive application data for plural windows of the displayable area. Each window defines the whole or a subset of a corresponding presentation space.

Abstract: A multiple window display system is provided for displaying data from different applications in a multi-tasking environment. The display system includes plural screen buffers (12.sub.1 to 12.sub.n) for storing character codes and attribute codes of data which may be displayed on the display screen. Task selection means (26) selectively couples the output of a single selected one of the plural screen buffers to the character generator (16) and attribute logic (18) at any given time. Address modification means (20.sub.1 to 20.sub.n, 22.sub.1 to 22.sub.n) permits changes to be made in the display windows. The software driver includes screen control blocks (32), window control blocks (34), presentation space control blocks (36), presentation spaces (38), and a screen matrix (40) in system memory. The presentation spaces (38) receive application data for plural windows of the displayable area. Each window defines the whole or a subset of a corresponding presentation space.

Abstract: A data display apparatus employs a raster scan cathode ray tube (1), a character refresh buffer (2) and three character row buffers (5,6,15) to address a character generator (3) in conjunction with a slice counter (4) or offset slice counter (18) under control of an events control module (20). This enables data within a partition on the CRT to be scrolled smoothly (scan-line-by-scan-line) and characters of different height (requiring different numbers of scans) to be displayed on the same row of the CRT.

Abstract: An interactive display system includes a display terminal on which an operator may display the data contained in windows (14.1, 14.2 . . . ) on formatted application data (PS 1, PS 2 . . . ) in selected viewports (15.1, 15.2 . . . ) on the screen 13. The system is provided with storage (4), both real and virtual, into which a presentation interface service (2) loads dynamically the entire formatted data (PS 1, PS 2 . . . ) of each application (list 1, list 2 . . . ) as it is invoked by the user. A screen manager (7) maps the data contained in the defined windows into locations (16.1, 16.2 . . . ) of a programmable symbol refresh buffer (6, 8) determined by the corresponding position of viewports (15.1, 15.2 . . . ) on the screen defined by the user and through which the windows are to be viewed.

Abstract: A personal computer attachment is provided for a display station of the type that communicates with a host computer (48). The display station has a display unit (10) and a keyboard (12) to which a personal computer system unit (14) is attached. The personal computer system unit typically supports floppy diskette drives (16) and a printer (18). The display unit includes a CRT (38), a regeneration buffer (42), a keyboard adapter (46) and a feature bus (44). The personal computer system unit includes a system bus, a microprocessor, memory, a keyboard adapter and I/O interface connected to the system bus. A display adapter (26 or 28) is connected to the I/O interface. An analog input switch (52) is disposed between the buffer (42) and the analog circuits driving the CRT (38). This switch has a second input from the display adapter (26 or 28) and is controlled from inputs from the keyboard (12) to selectively supply image data from the buffer (42 ) or the display adapter (26 or 28).

Abstract: An adjustable support for a display monitor includes a turntable to allow swivelling and carrying a pair of support tubes on which is mounted a slidable support beam. A carrier having cylindrical bearing surfaces co-operates with skid-pads on the support beam. By sliding the carrier with respect to the support beam the angle of the carrier and hence the angle of the display screen can be varied. A non-magnetic gas strut located in one of the support tubes compensates for the weight of the monitor/carrier assembly. The force exerted by the gas strut is shared between the support tubes by means of a pair of coupled rack and pinions which also allow convenient height adjustment of the support beam, carrier and display monitor.

Abstract: In a display terminal coupled to a computer and including a plurality of user interrupt devices for interactive communication with the computer, an apparatus for signalling to the user when the computer responds to a user interrupt comprises a counter arranged to measure a specified period of time by counting down to zero from an initial count value loaded from a register, a sensor triggered by the generation of an interrupt to cause the counter to begin measurement of the said specified period of time, and a further sensr coupled to an alarm via a logic gate to provide an audible signal only when the period of time between the generation of the interrupt and the computer response exceeds the specified period of time measured by the counter.

Abstract: The invention concerns a graphics display system of the kind having a refresh raster display device, a line clipping mechanism for clipping line primitives for viewing in a selected rectangular viewport having horizontal and vertical edges parallel to the X and Y axes respectively of the display area of the display device, and a vector-to-raster converter for converting the clipped lines to patterns of discrete pels in a refresh buffer, the vector-to-raster converter including an incremental line drawing mechanism responsive to line information supplied by the clipping mechanism to draw the line starting at one endpoint and proceeding towards the other.

Abstract: In order to compensate for image distortion introduced into a digitally-controlled raster-scan CRT by the finite video amplifier rise and fall times, the digital video drive waveform is subject to selective pulse stretching to extend where possible the duration of pels which represent critical features of the image. This is achieved by decoding means for examining each pel at least in relation to its two immediate neighbors on either side in order to detect predetermined relationships between the values of the pels, and retiming means for selectively advancing or delaying the transitions between consecutive pels of different value in accordance with the relationships so detected.

Abstract: A mirror array light valve is described comprising a transparent substrate, a plurality of post members arranged in a regular array on said substrate, and a plurality of deflectable square, rectangular, hexagonal or the like light-reflecting elements arranged in a regular array on said post members such that a post member is positioned under a corresponding corner of each element; methods for making the mirror array light valve are also described.

Abstract: A tiltable and/or rotatable support for a display device which includes a locking mechanism 19, 20, 21, 22, 23, 24 operable to lock the support in a selected tilt position while still permitting swivel adjustment. The support may be provided as a stand-alone unit or formed integral with the base of the display device.

Abstract: A tiltable and/or rotatable support for a display device includes a cam operated locking mechanism operable to positively clamp the support in a selected swivel and/or tilt position and limiting the amount of tilt and swivel to predetermined amounts. The locking mechanism is operated by means of a lever extending through a horizontal slot in the base and is adjustable to compensate for axial tolerance build-up which could otherwise lead to malfunction. The support may be provided as a stand-alone unit or formed integral with the base of the display device.

Abstract: In a shadow mask cathode ray tube for use with a light pen, the elemental phosphor areas emissive of red light comprise a blend of a red-emissive phosphor with silver-activated cadmium sulphide (CdS:Ag), the CdS:Ag being present in an amount from 10% to 30% by weight of the blend. In the preferred embodiment the blend comprises approximately 20% by weight of CdS:Ag and 80% by weight of industry standard P22R phosphor.

Abstract: A display management system for one or more large plasma gas panel displays (11) is organized to split the display management operations between a host processor (20), a system microprocessor (21) and a picoprocessor (27). The picoprocessor (27) is the heart of a common internal bus (31) plasma display adapter (22). The program for the display is downloaded from the host processor (20) to the system microprocessor (21). The microprocessor generates op codes and initializes display parameters. The plasma display adapter provides control for the plasma panel interface, serialization of character generator data, translates display position addresses for absolute cartesian coordinates to panel address, and computes the boundaries of display panel write and erase operations. Interaction between the system microprocessor and the plasma display adapter is minimized by a code list contained in the microprocessor memory and fetched by direct memory access.

Abstract: A display management system for one or more large plasma gas panel displays (11) is organized to split the display mangement operations between a host processor (20), a system microprocessor (21) and a picoprocessor (27). The picoprocessor (27) is the heart of a common internal bus (31) plasma display adapter (22). The program for the display is downloaded from the host processor (20) to the system microprocessor (21). The microprocessor generates op codes and initializes display parameters. The plasma display adapter provides control for the plasma panel interface, serialization of character generator data, translates display position addresses for absolute cartesian coordinates to panel address, and computes the boundaries of display panel write and erase operations. Interaction between the system microprocessor and the plasma display adapter is minimized by a code list contained in the microprocessor memory and fetched by direct memory access.

Abstract: A display management system for one or more large plasma gas panel displays (11) is organized to split the display management operations between a host processor (20), a system microprocessor (21) and a picoprocessor (27). The picoprocessor (27) is the heart of a common internal bus (31) plasma display adapter (22). The program for the display is downloaded from the host processor (20) to the system microprocessor (21). The microprocessor generates op codes and initializes display parameters. The plasma display adapter provides control for the plasma panel interface, serialization of character generator data, translates display position addresses for absolute cartesian coordinates to panel address, and computes the boundaries of display panel write and erase operations. Interaction between the system microprocessor and the plasma display adapter is minimized by a code list contained in the microprocessor memory and fetched by direct memory access.

Abstract: A step waveform generator includes a cup and bucket circuit in which charging and discharging a cup capacitor (C1) with predetermined units of charge is achieved, in response to a train of pulses supplied to its input terminal (1), by means of an operational amplifier (2) continuously monitoring the voltage across the cup capacitor and alternately supplying charging current and discharging current from a first and second constant current source (I1 and I2) respectively via separate feedback loops (T3, T2 and T4, T7, T6) of the amplifier. The constant currents, or multiples or sub-multiples of the constant currents, providing each individual unit of charge, are generated by current mirrors (T8, T9, T10) and added sequentially to a bucket capacitor C2. The size of each individual step of the resultant voltage waveform derived from the bucket capacitor and appearing at output terminal 4 depends upon the combination of mirrored increments of current selected by switch (S1, S2) and added to the bucket capacitor.

Abstract: A gas panel can provide optical data readout in an essentially serial manner for copying, communication, interaction and indication. This is accomplished by using substitute sustain cycles for reading particular addresses. A complement sustain signal obtained through the address selection circuitry is superimposed on a partial sustain signal to produce the substitute sustain signal. This provides a complete sustain cycle for the selected address(es) only. Flashes of light at the addressed positions indicate storage of logical "1s" at such addresses.

Abstract: A raster-scanned CRT device includes auxiliary vertical deflection means operable during each scan line of the raster to deflect the electron beam selectively between adjacent pairs of uniformly spaced image lines on the screen. Control logic operates in response to video information representing an image to be displayed to write image pels on the screen during two successive field scans of the raster. The auxilliary deflection means is controlled so that the entire image is formed on the image lines, and the field scan in which the pels are allocated for display is selected on-the-fly for successive portions of the input video in such a way that pel imbalance between the two fields constituting the final image is minimized.