International Business Machines Corporation

Richard N Mendelson

Ernest Nelson Mandese

Francis M Bonevento

Andrew B McNeill

Dhruvkumar M Desai

Sammy D Dodds

Chester A Heath

Douglas R Chisholm

Donall G Bourke

Joseph P McGovern

Douglas M O'Neal

Leo A Sharp, Jr

Ralph M Pipitone

Douglas R Chrisholm

Arthur J Heimsoth

Luis Madruga

A data handling arrangement for a computer system, with particular application to multimedia systems, allows device adapters (control units) attached to the system to autonomously (without interrupting the system processor) control processing of a data stream of arbitrary length through memory buffers which are smaller than the stream. In this (stream processing) operation, data constituting the data stream flows through devices controlled by the adapter in succession, and is held in shared memory buffers as it passes between devices. The adapters are prepared for the stream processing operation by a system processor, indicate their preparation status to the processor, receive an initiating signal from the processor, and then proceed to direct the operation to completion without further assistance from the processor. In the operation, the adapters coordinate usage of the memory buffers by respective devices. Coordination is accomplished using a notification signalling protocol defined during preparation of the adapters.

Data streaming between peer subsystems of a computer system

A coded logical interrupt signal is sent between system or subsystem units in a data processing system. The logical interrupt is sent by a sending unit, that requests the interrupt, and is sent to a receiving unit that the sending unit wishes to interrupt. These coded logical interrupts are accumulated in the receiving unit. When the receiving unit is actually physically interrupted by control of the processor in the unit, all logical interrupts that have been accumulated are processed. The logical interrupt may be coded to indicate sending unit, that is the source of the interrupt, and the action being requested by the sending unit. If the interrupt includes only source information, the action information is sent separately by the sending unit to memory in the receiving unit. If the interrupt includes both source identification and action information, the receiving unit can interpret source and action directly from the interrupt.

Peer to peer computer-interrupt handling

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. An interrupt controller is coupled to the microprocessor and bus for recognizing delivery of an interrupt signal and for periodically generating an interrupt reset signal and delivering reset signals to all of the input/output devices simultaneously for setting all of the devices to a condition indicative of no request for access to said microprocessor.

Personal computer system with interrupt controller

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. The host processor reads the DIIP to determine which logical devices have at least one logical interrupt pending for an indirect command. A plurality of logical interrupts for a single logical device may be cleared with a single reset interrupt command from the host processor.

Interrupt handling for a computing system with logical devices and

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.

Command delivery for a computing system for transferring data between a

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.

Command delivery for a computing system for transfers between a host and

There is disclosed apparatus and a method for extending a parallel channel of the host processor over a serial link to a remote peripheral device. The apparatus includes a microprocessor within I/O channel extension logic which responds to either instructions or data from a host processor. The instructions are of the type commanding the I/O device to perform a specific operation and the data is provided in response to requests for data from the I/O device. The channel extension logic is coupled to the host processor's channel and thus is able to obtain data from the host storage by cycle steal techniques. Within the channel extension logic are means to serialize the information and transmit it in a serial manner over the link. The microprocessor within the channel extension logic creates a frame, including a control byte, which identifies the type of information followed by the data, which frame is then communicated over the serial link to the I/O device. The I/O device also includes a microprocessor and associated logic which responds to the frames communicated by the channel extension logic and generates a frame consisting of a control byte identifying the information type and associated data which is then communicated back over the serial link to the channel extension logic to request action by the channel extension logic or indicate completion of the operation. The I/O device may, for instance, request data be obtained from or stored in the host memory by cycle steal techniques and thereby utilize the features of the host and host channel despite only being coupled thereto by a serial link.

Apparatus and method for extending a parallel channel to a serial I/O

An I/O controller is provided for transferring data between a host processor and a plurality of I/O devices wherein the host processor generates a transfer command and each of the plurality of I/O devices generates multiple asynchronous service requests for transfer to the host processor. Control circuitry is provided for controlling the transfer of the service requests from the plurality of I/O devices to the host processor. The control circuitry generates a host processor interrupt signal for application to the host processor, such that in response to the host processor interrupt signal, the host processor generates the transfer command to allow the control circuitry to transfer the service requests to the host processor.

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Highland Beach, FL, United States of America

Richard N Mendelson