Abstract: In a distributed data processing system running multiple applications on the client system resources specific to an application which have no impact on the overall display at the server, are stored in application address space. Resources which have an effect on the overall system and which are managed in the client system are stored in common presentation address in the client system. Resources which have an overall effect and are managed in the server system are stored in the display server system.

Abstract: In a data processing network having a first processor (for example, a programmable workstation), a second processor (for example a host computer) and a communication system linking said first processor and said second processor, control logic associated with said first processor is operable to manage the flow of information between said first processor and said second processor on behalf of one or more application programs running on said first processor. The control logic is responsive to calls issued by, or on behalf of, and application invoked by a user at the first processor to determine if a file or, set of files, associated with the calling application is the most up-to-date version of the file, or set of files available. The most up-to-date versions are always stored at the second processor (ie: the host). A comparison is made between the files and their levels currently available at the first processor (work station) and the up-to-date files held at the second processor (host).

Abstract: In a data processing network having a first processor (for example, a programmable workstation), a second processor (for example a host computer) and a communication system linking the first processor and the second processor, control logic associated with the first processor manages the flow of information between the first processor and the second processor on behalf of one or more application programs running on said first processor. The control logic responds too calls issued by, or on behalf of, an application invoked by a user at the first processor to determine if a file or, set of files, associated with the calling application is the most up-to-date version of the file, or set of files available. The most up-to-date versions are always stored at the second processor (i.e.: the host). A comparison is made between the files and their version levels currently available at the first processor (work station) and the up-to-date files held at the second processor (host).

Abstract: A workstation and data processing network in which having an application selection mode simultaneously displaying representations of both local and remote applications from which either remote or local applications may be started using a common selection procedure. When a remote application is selected a surrogate application is run on the workstation which establishes a communication with the remote processor. The provision of this common selection procedure means that the workstation is easier to use.

Abstract: The invention provides a data processing network having a first processor, a second processor and a communication system linking said first processor and said second processor characterized in that when said first processor issues a call for triggering said second processor to allocate a real identifier for an entity, control logic associated with said first processor and responsive to said call from said first processor allocates a local identifier available for immediate use by said first processor and subsequently transforms between said local identifier and said real identifier. The invention both recognizes and solves the problem of a first processor being delayed while waiting for an identifier to be supplied by a second processor. Control logic associated with the first processor provides a local identifier for use by the first processor without having to wait for the real identifier from the second processor.

Abstract: A method and apparatus for continuously updating a display of the coordinates of a light pen as it moves across a display screen involves executing a single iteration of an approximation calculation every refresh cycle of the display. The absolute screen coordinates are updated by the light pen tracking system and converted to application parameters written by the host computer into the display buffer work space. The orthogonal displacements, dx and dy, from a fixed reference point are determined. The distance and direction values from the reference point are converted to character form and inserted in the display buffer.