Abstract: An application request for off-screen VRAM is satisfied transparently to the application by allocating off-screen VRAM, if available, or system RAM if off-screen VRAM is unavailable. In addition, a list is kept of previous memory requests so that requests which were satisfied by allocating system RAM can be switched to off-screen VRAM, if such off-screen VRAM should later become available. Allocation of off-screen VRAM is controlled by a device driver that responds to various application memory requests and controls the off-screen VRAM resources, among other things. The device driver receives an allocation request for off-screen VRAM and determines whether the request may be honored with available off-screen VRAM resources. If the request can be honored with available off-screen VRAM resources, the device driver allocates a portion of the available off-screen VRAM resources to honor the request and decreases the amount of available off-screen VRAM resources.

Abstract: Disclosed is a support architecture that facilitates use of display device drivers containing a minimum of hardware-specific software code. A driver need support only a relatively few common functions, which act as building blocks for the larger, more complex operations typically requested by graphics engines. In order to mediate between the limited-instruction-set device driver and the various higher-level graphics engines, the invention includes a series of translation modules that simplify engine-originated instructions into simpler graphic components. A video manager supervises routing of instructions to the specific drivers they designate, and serializes access to hardware components so that graphic commands execute atomically (i.e., without interruption). The invention can accommodate multiple device drivers in parallel or serial configurations.

Abstract: Disclosed is a support architecture that facilitates use of display device drivers containing a minimum of hardware-specific software code. A driver need support only a relatively few common functions, which act as building blocks for the larger, more complex operations typically requested by graphics engines. In order to mediate between the limited-instruction-set device driver and the various higher-level graphics engines, the invention includes a series of translation modules that simplify engine-originated instructions into simpler graphic components. A video manager supervises routing of instructions to the specific drivers they designate, and serializes access to hardware components so that graphic commands execute atomically (i.e., without interruption).

Abstract: A display memory manager allocates and deallocates off-screen video memory by dividing the memory space into a plurality of lapping and non-overlapping regions each capable of storing a different amount of digitized display data, and creating a linked list data structure indicative of the allocated and unallocated regions and various combinations of the unallocated regions. Upon receiving a request for off-screen display memory the display memory manager traverses the linked list data structure searching for a region, or combination of regions, large enough to store the requested amount of digitized display data. Once a region or combination of regions has been found and allocated, the linked list data structure is updated to indicate that the new regions are now allocated and hence unavailable to a subsequent requested allocation unless deallocated.

Abstract: A system and means for selecting a proper protocol for a pointing device used in a computer system having a data store, a main processing unit, data input and output means, is disclosed. The selecting means includes means, coupled to the pointing device, for analyzing a data stream from the pointing device; means, coupled to the analyzing means, for determing a protocol based on the analyzed data stream; and means, coupled to the determing means, for selecting a device state from a plurality of device states for enabling the pointing device to operate in the computer system.

Abstract: Disclosed is a support architecture that facilitates use of display device drivers containing a minimum of hardware-specific software code. A driver need support only a relatively few common functions, which act as building blocks for the larger, more complex operations typically requested by graphics engines. In order to mediate between the limited-instruction-set device driver and the various higher-level graphics engines, the invention includes a series of translation modules that simplify engine-originated instructions into simpler graphic components. A video manager supervises routing of instructions to the specific drivers they designate, and serializes access to hardware components so that graphic commands execute atomically (i.e., without interruption). The invention also includes a graphics library containing device-level instruction sets, as well as the on-board capability to execute those commands, for a broad range of graphic operations.

Abstract: Disclosed is a support architecture that facilitates use of display device drivers containing a minimum of hardware-specific software code. A driver need support only a relatively few common functions, which act as building blocks for the larger, more complex operations typically requested by graphics engines. In order to mediate between the limited-instruction-set device driver and the various higher-level graphics engines, the invention includes a series of translation modules that simplify engine-originated instructions into simpler graphic components. A video manager supervises routing of instructions to the specific drivers they designate, and serializes access to hardware components so that graphic commands execute atomically (i.e., without interruption).

Abstract: A method and system for permitting simultaneous communication between a data processing system and input pointing devices of multiple types. During the initialization of an operating system, each input pointing device which is coupled to a data processing system is automatically identified. Thereafter, in response to each input from any one of the identified input pointing devices, a particular software routine is automatically selected, thus permitting each identified input pointing device to communicate with the data processing system.

Abstract: A controller in a personal computer operating system continuously monitors for signals indicating continued powering of an attached keyboard, mouse or other pointing device. Loss of this signal is caused by the accidental or intentional loss of power to the external device or by physically disconnecting the device. Absence of the signal causes the setting of a timeout bit in the device status byte. When the attached device signals that it has successfully become re-powered, the initialization program routine of the operating system is recalled so as to return the device to on-line status without requiring a restart of the entire operating system.

Abstract: A method and system for permitting communication between a data processing system and input pointing devices of multiple types. During the initialization of an operating system, a particular selectable software routine is automatically selected in response to an automatic determination that a particular type of input pointing device is coupled to the data processing system. Thereafter, the particular selectable software routine which was automatically selected permits communication between the data processing system and the particular type of input pointing device which is coupled to the data processing system.

Abstract: A computer system includes a keyboard which includes cooperatively operating therewith a keyboard device driver to enable the keyboard to interface with an operating system and applications program running within the computer system. Further types of input devices, such as handprint terminals, light pens, etc., can be employed in place of a keyboard to interact with the operating system and application programs running within the computer system. A keyboard device driver emulator is provided which transforms input data from the alternate input device so as to have said data appear to be keyboard generated data which is then transmitted to the operating system and applications running within the computer system. The invention also relates to a method of operating a computer system with an input device which is not a keyboard, but operating the system as if the input device were a keyboard by transforming the data from the input device to make it appear to be keyboard generated data.