摘要:
According to one aspect of the invention, an apparatus includes a first processor coupled to a first system bus to provide data to a cache and a memory, and a second processor coupled to the first system bus and a second abbreviated system bus to receive read data from said first system bus. In accordance with a further aspect of the invention, an apparatus includes means for correcting errors in memory. In accordance with a further aspect of the invention, an apparatus includes a number of computing systems each including a memory device mounted on an infrequently replaced hardware unit, and capable of communicating with the number of computing systems. In accordance with another aspect of the invention, an apparatus includes a counter, means for detecting a selected state of said counter, and means, responsive to output signals from said counter, for selectively permitting or inhibitting transfer of data fed to a recirculating state device. In accordance with a further aspect of the invention, an apparatus includes a first means for providing a first clocking signal, a second means for providing a second clocking signal, means for providing an error signal responsive to an offset between edges of the first and second clocking signals.
摘要:
A fault tolerant computer system is described in which a direct memory access controller examines the check bit data on every data element that is accessed by the system. The address of any data element that is found to have an error in the check bit data is stored by the direct memory access controller, the check bit data is used by the direct memroy access controller to correct the error, and the corrected data element is rewritten to the original storage address. By the use of this arrangement, the central processing unit or units of the computer system are free to perform other tasks, thus improving system throughput, and preventing the accumulation of data element errors in the memory.
摘要:
Method and apparatus for controlling initiating of bootstrap loading in a computer system having first and second discrete computing zones is disclosed. Each computing zone includes a status register for storing an operating system run (OSR) bit indicating that the zone has initiated bootstrap loading. A cable connects the computing zones to allow the first and second zones to read the status registers in the second and first zones, respectively. A CPU in each zone only enables initiation of bootstrap loading if the OSR bit in the other zone is not set.
摘要:
Method and apparatus for testing the operation of modules for use in a fault tolerant computing system that consists of two distinct computing zones. Diagnostic testing is performed when the system is powered on, the modules being subjected to module, zone and, if both zones are available, system diagnostic tests. Indications of faults detected during diagnostic testing are stored in an EEPROM on each module. Such fault indications can be cleared in the field by correcting the fault condition and successfully rerunning the diagnostic test during which the fault was detected. Indications of operating system detected faults are also stored in each module EEPROM. However, such fault indications are not field clearable.
摘要:
According to one aspect of the invention, an apparatus includes a first processor coupled to a first system bus to provide data to a cache and a memory, and a second processor coupled to the first system bus and a second abbreviated system bus to receive read data from said first system bus. In accordance with a further aspect of the invention, an apparatus includes means for correcting errors in memory. In accordance with a further aspect of the invention, an apparatus includes a number of computing systems each including a memory device mounted on an infrequently replaced hardware unit, and capable of communicating with the number of computing systems. In accordance with another aspect of the invention, an apparatus includes a counter, means for detecting a selected state of said counter, and means, responsive to output signals from said counter, for selectively permitting or inhibitting transfer of data fed to a recirculating state device. In accordance with a further aspect of the invention, an apparatus includes a first means for providing a first clocking signal, a second means for providing a second clocking signal, means for providing an error signal responsive to an offset between edges of the first and second clocking signals.
摘要:
Resets on a data processing system are targeted to specific locations of that processing system and have different effects. Some resets are transparent to instruction execution while other resets will interrupt the normal execution of instructions. In addition, in a multi-zone environment resets in one zone do not automatically propagate to the other zone; instead, each zone generates its own resets.
摘要:
In a processing system having duplicate sets of elements, often called rails, to move rail unique data from one set of elements to the other set of elements, the unique data is moved to a scratchpad memory and then copied into a common memory after certain error checking is disabled.
摘要:
A process for transferring data via DMA between a system resource and a controller via switching logic. During a setup write transaction, the switching logic is set up to enable DMA data to be transferred between a particular system memory and a selected system resource. The setup write transaction also is used to initialize the DMA byte counter. During a subsequent write transaction, DMA pointer registers are initialized with appropriate starting addresses. The controller then transmits a DMA start code and the system resource responds by transmitting an acknowledge code. At that time, DMA data is transmitted between the controller and the system resource via the switching logic.
摘要:
In a first aspect, a method of synchronizing at least two computing elements that each have clocks that operate asynchronously of the clocks of the other computing elements includes selecting one or more signals, designated as meta time signals, from a set of signals produced by the computing elements, monitoring the computing elements to detect the production of a selected signal by one of the computing elements, waiting for the other computing elements to produce a selected signal, transmitting equally valued time updates to each of the computing elements, and updating the clocks of the computing elements based on the time updates.In a second aspect, fault resilient or fault tolerant computers are produced by designating a first processor as a computing element, designating a second processor as a controller, connecting the computing element and the controller to produce a modular pair, and connecting at least two modular pairs to produce a fault resilient or fault tolerant computer. Each computing element of the computer performs all instructions in the same number of cycles as the other computing elements.Computer systems include one or more controllers and at least two computing elements. System is provided for intercepting I/O operations by the computing elements and transmitting them to the one or more controllers.
摘要:
A dual processor data processing system having interprocessor error checking includes a first central processing unit executing a series of instructions. A second central processing unit executes the same series of instructions independently of and in synchronism with the first central processing unit. A first data bus is coupled to the first central processing unit for receiving data to be input to the first central processing unit and a second data bus is coupled to the second central processing unit for receiving data to be input to the second central processing unit. Error checking devices are coupled to the first and second data busses for checking data transmitted over the first and second data busses and for detecting errors on I/O reads prior to delivery of the data to the first and second central processing units. The error checking devices include comparison means for indicating an error when the data on the first and second data busses are unequal. Error isolation devices are responsive to an error detected from the error checking means for analyzing the cause of error while maintaining system synchronization.