Intel Corporation

Siemens Ak.

David L Budde

David B Johnson

David G Carson

Craig B Peterson

Anthony L Cornish

Doran K Wilde

Stephen R Colley

David A Stamm

Henry M Blume, Jr

Konrad K Lai

Mark S Myers

Brad W Hosler

Ronald J Ebersole

Michael T Imel

Allan L Goodman

Stephen L Domenik

Gerhard Bier

Sven-Axel Nilsson

Robert Riches

James D Howard

Glen Myers

Robert P Voll

A data processor bus in which information is transferred between agents attached to the bus by issuing request packets that request data from an agent on the bus and reply packets that return data requested by a request packet. A control method mixes request-and-reply packets on the bus by determining the use of a next-bus cycle using arbitration, reply deferral, and specification lines and the state of a grant queue and a pipe queue in accordance with a specified protocol. A request is forced to take the next available bus cycle upon the condition that there is an agent identified in the great queue and the pipeline queue is not full. A reply packet is forced to take the next available bus cycle upon the condition that the pipeline queue is full. A reply packet is forced to take the next available bus cycle upon the condition that the grant queue is empty and the pipeline queue is not empty. Giving requests precedence over replies to allows the pipeline to be kept as full as possible. A replying agent assigned to the highest priority slot 1 in the pipeline queue is allowed to defer its own slot in the pipeline queue until a later time to thereby permit a transaction in Slot 2 of the pipeline queue to be completed before the one ahead of it.

Method of increasing the bandwidth of a packet bus by reordering reply

A computer system operative during an initialization phase to initialize modules of the system and during a subsequent non-initialization phase to transfer information between the initialized modules. A module bus (MB) has 32 signal lines beginning with a least-significant-bit signal line and ending with a most-significant-bit signal line. The bus (MB) connects the modules for data transfers after the initialization phase over bidirectional address lines and data lines connected to the module bus. A system support module (SSMI) starts the initialization phase by energizing an initialization signal line (INIT). In response, a processor (GDP) generates identification command information over the bus (MB) that continas a first data record and a second data record. The first data record is comprised of bits equal to the number of signal lines in the 32-bit module bus, with only one logical one in the first data field, the position of the logical one advancing consecutively from the least significant bit position to the most significant bit position for each successive identification command generated by the processor. The second data record is an identification code uniquely identifying the one of the modules activated by the first record to receive the second record and hence its identification code.

High-availability computer system with a predefinable configuration of

When a load instruction is encountered, a read operation is sent to the bus control logic, the register is marked as busy, and execution proceeds to the next instruction. When an instruction is executed, it proceeds providing that its source and destination registers are not marked busy; otherwise the instruction is retried. When data are returned as the result of a read operation, the destination register(s) are marked as not busy.

Register scorboarding on a microprocessor chip

A number of intelligent nodes (bus interface units-BIUs and memory control units-MCUs) are provided in a matrix composed of processor buses (105) with corresponding error-reporting and control lines (106); and memory buses (107) with corresponding error-reporting and control lines (108). Error-detection mechanisms deal with information flow occuring across area boundaries. Each node (100, 101, 102, 103) has means for logging errors and reporting errors on the error report lines (106, 108). If an error recurs the node at which the error exists initiates an error message which is received and repropagated on the error report lines by all nodes. The error message identifies the type of error and the node ID at which the error was detected. Confinement area isolation logic in a node isolates a faulty confinement area of which the node is a part, upon the condition that the node ID in an error report message identifies the node as a node which is a part of a faulty confinement area. Logic in the node reconfigures at least part of the system upon the condition that the node ID in the error report message identifies the node as a node which is part of a confinement area which should be recofigured to recover from the error reported in the error report message.

Apparatus for recovery from failures in a multiprocessing system

A number of intelligent nodes (bus-interface units-BIUs and memory-control units-MCUs) are provided in a matrix composed of processor buses (105) with corresponding error-reporting and control lines (106); and memory buses (107) with corresponding error-reporting and control lines (108). Each node (100, 101, 102, 103) has means for logging errors and reporting errors on the error-report lines (106, 108). Processor modules (110) and memory modules (112) are each connected to a node which controls access to a common memory bus (107). Each node includes means (a married bit-170 and a shadow bit-172) for marrying modules in pairs such that each module in the pair tracks the operations directed to the module pair, and each module in the pair alternates with the other module in the handling of requests or replies. Each node registers the ID of the other node in a spouse ID register. Comparison logic (162, 164) in each node resets the married bit upon the condition that the node ID (identifying the node at which the error occurred) in an error-report message is equal to the ID stored in the spouse ID register, thus identifying the spouse node (the partner of the node in which the comparison logic is located) as the source of the error. Resetting the married bit splits apart the primary/shadow pair, so that the error-free module takes over and ceases to alternate with its partner.

Apparatus for redundant operation of modules in a multiprocessing system

A number of intelligent bus interface units (100) are provided in a matrix of orthogonal lines interconnecting processor modules (110) and memory control unit (MCU) modules (112). The matrix is composed of processor buses (105) and corresponding control lines; and memory buses (107) with corresponding control lines (108). At the intersection of these lines is a bus interface unit node (100). The bus interface units function to pass memory requests from a processor module to a memory module attached to an MCU node and to pass any data associated with the requests. The memory bus is a packet-oriented bus. Accesses are handled by means of a series of messages transmitted by message generator (417) in accordance with a specific control protocol. Packets comprising one or more bus transmission slots are issued sequentially and contiguously. Each slot in a packet includes an opcode, address, data, control, and parity-check bits. Write-request packets and read-request packets are issued to the memory-control unit. The memory-control unit responds with reply packets. A message controller (416), bus monitor (413), and pipeline and reply monitor ( 414), run the memory bus in a three-level pipeline mode. There may be three outstanding requests in the bus pipeline. Any further requests must wait for a reply message to free-up a slot in the pipeline before proceeding. Request messages increase the length of the pipeline and reply messages decrease the length of a pipeline. A control message, called a blurb, does not affect the pipeline length and can be issued when the pipeline is not full. The different messages are distinguished by three control signals (405) that parallel the data portion of the bus. The message generator (417) and interface logic (404) drive these control lines to indicate the message type, the start and end of the message, and possible error conditions. The pipeline and reply monitor (414) and the message controller (416) cooperate to insert a reply to a particular request in the pipeline position corresponding to the particular request that invoked the reply.

Interface for use between a memory and components of a module switching

An arbitration mechanism comprising a request FIFO (408) for storing ones and zeros corresponding to received requests in the order that they are made. A one indicates that the request was made by the module in which the FIFO is located, and a zero indicates that the request was made by one of a number of other similar modules. The request status information from the other modules is received over signal lines (411) connected between the modules. This logic separates multiple requests into time-ordered slots, such that all requests in a particular time slot may be serviced before any requests in the next time slot. A store (409) stores a unique logical module number. An arbiter (410) examines this logical number bit-by-bit in successive cycles and places a one in a grant queue (412) upon the condition that the bit examined in a particular cycle is a zero and signals this condition over the signal lines. If the bit examined in a particular cycle is a one, the arbiter drops out of contention and signals this condition over the signal lines (411). This logic orders multiple requests within a single time slot, which requests are made by multiple modules, in accordance with the logical module numbers of the modules making the requests. The grant queue (412) stores status information (ones and zeros) corresponding to granted requests in the order that they are granted--a one indicating that the granted request was granted to the module in which the grant queue is located, and a zero indicating that the granted request was granted to one of the other modules. The granted request status information from the other modules is received over the signal lines (411). This logic separates multiple granted requests such that only one request corresponding to a particular module is at the head of any one grant queue at any one time.

Arbitration means for controlling access to a bus shared by a number of

A number of intelligent crossbar switches (100) are provided in a matrix of orthogonal lines interconnecting processor (110) and memory control unit (MCU) modules (112). The matrix is composed of processor buses (105) and corresponding error-reporting lines (106); and memory buses (107) with corresponding error-reporting lines (108). At the intersection of these lines is a crossbar switch node (100). The crossbar switches function to pass memory requests from a processor to a memory module attached to an MCU node and to pass any data associated with the requests. The system is organized into confinement areas at the boundaries of which are positioned error-detection mechanisms to deal with information flow occurring across area boundaries. Each crossbar switch and MCU node has means for the logging and signaling of errors to other nodes. Means are provided to reconfigure the system to reroute traffic around the confinement area at fault and for restarting system operation in a possibly degraded mode.

Apparatus of fault-handling in a multiprocessing system

An execution unit which is part of a general-purpose microprocessor, partitioned between two integrated circuit chips, with the execution unit on one chip and an instruction unit on another chip. The execution unit provides the interface for accessing a main memory to thereby fetch data and macroinstructions for transfer to the instruction unit when requested to do so by the instruction unit. The execution unit receives arithmetic microinstructions in order to perform various arithmetic operations, and receives access-memory microinstructions in order to develop memory references from logical addresses received from the instruction unit. Arithmetic operations are performed by a data manipulation unit which contains registers and arithmetic capability, controlled by a math sequencer. Memory references are performed by a reference-generation unit which contains base-and-length registers and an arithmetic capability to generate and check addresses for referencing an off-chip main memory, and is controlled by an access sequencer.

Microinstruction execution unit for use in a microprocessor

A buffer utilizing MOS devices for coupling a computer input data line and a computer output data line to a single input/output port is disclosed. The buffer receives a control signal generated by computer port control means at the beginning of any buffer cycle when data is to be accepted by the buffer.

Programmable single chip MOS computer

An MOS digital computer incorporated on a single chip (monolithic structure) which includes a central processing unit (CPU), random-access memory (RAM), and a programmable read-only memory (PROM). A program counter is used to fetch instructions stored in the erasable PROM, and may also be used to fetch instructions from an external memory. The PROM may also be externally addressed for testing, or may be electrically isolated from the remainder of the computer to permit execution of external instructions for testing the CPU and RAM.

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Portland, OR, United States of America

David L Budde