Abstract: A particular, appropriate BIOS extension image is selected from a potential set of multiple images for use in initializing a peripheral adapter. To enable proper selection, the peripheral adapter includes a firmware image of a BIOS extension that is storable on the peripheral adapter. The firmware image includes a nominal identifier of a BIOS extension and a set of one or more firmware markers that are compliant with the valid identification of the BIOS extension by a first predetermined host computer and that ensures that the firmware image is identifiable by a second predetermined host computer as being invalid. By specific selection of the firmware markers, these markers can be used to uniquely enable a predetermined one of the host processors to appropriately execute an appropriate BIOS extension image.

Abstract: A host adapter contains a RISC processor, a local memory, and a memory management unit that permits the RISC processor and a host computer system to access a local memory. The host computer system writes command descriptions directly into the local RAM. The RISC processor retrieves and processes the command descriptions. The local RAM may be divided into numbered command description blocks having a fixed size and format. In standard bus protocols, such as SCSI-2, block numbers are used as tag messages. Such tag messages allow the host adapter to quickly identify information used when an SCSI I/O request is resumed. The command description blocks may be linked into lists, including an active list containing command description blocks that are ready for the RISC processor and a free list containing command description blocks that are available for use by the host computer.

Abstract: A single instance of a device driver is used to control multiple peripheral devices in a computer system having a central processor for executing an operating system, a memory, and first and second interface buses permitting interconnection of peripheral adapters with the central processor. The interface buses each correspond to different classes of peripheral adapters. The device driver includes an initialization routine for scanning the interface buses to identify predetermined functionally related peripheral adapters. A communications path is provided between the operating system and each of the peripheral adapters of a form appropriate for the particular interface bus connected to each adapter. A control path is also provided between each of the peripheral adapters and the operating system of a form appropriate for the particular interface bus connected to each adapter.

Abstract: An input/output port address selection circuit for a device that couples to a local bus of a computer operates in two modes. In a first mode, the I/O port address is maintained as the last I/O port address saved. In the second mode, the selection circuit changes the I/O port address and saves the change when the circuit is reset. A computer user resolves I/O port address conflicts by placing the selection circuit in the second mode then resetting the system until the conflict is resolved and the system works properly. The selection circuit is then placed and left in the first mode so that the non-conflicting address is reused. Non-volatile memory, an electrically erasable-programmable read-only memory, is used for saving an index which indicates the last I/O port address set. The non-volatile memory is changed when the selection circuit is operated in the second mode.