Abstract: A microprocessor system includes a processor unit, one or more subsystem adapter units, optional I/O devices which may attach to the adapters, and a bus interface. Memory in the processor and memory in the adapters are used by the system as a shared memory which is configured as a distributed First In First Out (FIFO) circular queue (a pipe). Unit to unit asynchronous communication is accomplished by placing self-describing control elements on the pipe which represent requests, replies, and status information. The units send and receive self-describing control elements independent of the other units which allows free flowing asynchronous delivery of control information and data between units. The distributed, shares memory can be organized as pipe pairs between each pair of units to allow full duplex operation by using one pipe for outbound control elements and the other pipe for inbound control elements. The control elements have standard fixed header fields with variable fields following the fixed header.

Abstract: This disclosure relates to personal computer systems, and more particularly to a personal computer which provides for interrupt redirection of the activity of a microprocessor. The personal computer system has a multichannel bus for transferring data, a microprocessor for manipulating data and coupled to the bus, and a plurality of input/output devices coupled to the bus for receiving and delivering data for manipulation by the microprocessor. Each input/output device is capable of generating a logical interrupt signal indicative of a request for access to the microprocessor and of being remotely reset to a non-interrupt condition, and all of the devices deliver their logical interrupt signals through a common physical channel of the bus.

Abstract: A computing system including a host processor and at least one intelligent subsystem having attached devices, has two interrupt ports. The one intelligent subsystem and the attached devices are each viewed as a logical device by the host processor, and each is assigned a device identification number. The host processor provides direct and indirect commands to the logical devices. For direct commands, first physical interrupts are provided to the host processor serially from the logical devices through an Interrupt Status Port. For indirect commands, logical interrupts are stored in predetermined bit positions in a Device Interrupt Indentifier Port (DIIP) in accordance with the device identification numbers. A second single physical interrupt is provided to the host processor as long as there is at least one logical interrupt pending from at least one logical device as the result of an indirect command.

Abstract: A Command interface includes ports for transferring information between a host processor and at least one intelligent subsystem which may have attached devices. A Command Interface port receives either a direct command or an indirect command from the host processor, which commands are indicative of a type of operation to be performed by the one subsystem or an attached device. An Attention port receives a code from the host processor which is indicative of which one of the direct command or the indirect command is received at the Command Interface port, and which is also indicative of which of the one intelligent subsystem or a device is to execute the command. A command busy/status port receives a code from the one intelligent subsystem which is indicative of whether or not the Command Interface port and the Attention port are busy, and whether or not the one intelligent subsystem is accepting or rejecting commands. The host processor can read this port without altering or updating the code.

Abstract: A command interface includes ports for transferring information between a host processor and at least one intelligent subsystem which may have attached devices. A Command Interface port receives either a direct command or an indirect command from the host processor, which commands are indicative of a type of operation to be performed by the one subsystem or an attached device. An Attention port receives a code from the host processor which is indicative of which one of the direct command or the indirect command is received at the Command Interface port, and which is also indicative of which of the one intelligent subsystem or a device is to execute the command. A command busy/status port receives a code from the one intelligent subsystem which is indicative of whether or not the Command Interface port and the Attention port are busy, and whether or not the one intelligent subsystem is accepting or rejecting commands. The host processor can read this port without altering or updating the code.