A radiation hardened register file renders a central processing unit intrinsically hard to the disruptive effects of nuclear radiation by providing means for establishing a valid rollback point for each computer instruction operation performed in the central processing unit. Dual data register images provide alternate locations for storing data operands in the register file. A pointer register stores a signal the truth state of which indicates which of the two images currently provides the proper place to store information presently being written and also provides an indication of the current location of assured valid signals for a recovery operation and resumption of normal computer functions subsequent to a disruptive event. Pointer save registers are used to store the latest value of the signal stored in the pointer registers, thereby also preserving valid pointer information for recovery subsequent to a circumvented disrupting event. A master pointer register stores a signal indicating which of two alternate pointer save registers currently stores the appropriate signal for selecting the proper truth state for the signal in the pointer register.
A self correcting single event upset-hardened CMOS register comprises a master portion and a slave portion. The master portion is coupled to a source of data and includes a feedback means such that said master portion can store said data during the first phase of a bi-phase clock signal. A slave portion including a second feedback path, has an input coupled to the output of said master portion and has an output which comprises the output of the register. An odd plurality of inverters is placed in series in the feedback path so as to isolate each node which is a possible site for high-energy particle impingement from other nodes in the loop and to attenuate and delay any resulting impulses such that the state of the error pulse cannot be maintained thus permitting the slave loop to remain in the state determined by the preceding data pulse.
A cosmic ray detector includes a cantilever with a first tip. The detector also includes a second tip and circuitry to provide a signal indicative of a distance between the first and second tips being such as would be caused by a cosmic ray interaction event.
A method and apparatus allows fault recovery in a digital computer based control system whereby system upsets induced by external transient noise conditions can be accommodated. A CPU is coupled to its main memory and its I/O interfaces by a common address/data bus, these three elements being susceptible to having data thereon or therein corrupted by transient noise. Also coupled to the bus, but in a hardened environment, are first and second supplemental memories which, under memory control, operate on alternating even and odd computational frames defined by the CPU's real-time clock to store the same words as are then being entered into the CPU's main memory. As computational frames are entered into one or the other of these two memories by eaves-dropping on the common bus, the other supplemental memory is transferring its contents to a backup memory which is also housed in the noise-immune environment. The backup memory is connected in a read-only mode to the address/data bus and, because of the manner of operation, always contains the computational frame that is delayed one cycle of the CPU's real-time clock from the frame in progress. Should a transient upset occur, it may be followed by a transfer of the information from the backup memory into the computer's main memory such that computations can then continue with data that is uncorrupted.
A radiation hardened or fail safe circuit is coupled between a peripheral data storage device, for example a disk drive, and its associated controller. The circuit includes an AND logic gate with two inputs: a write enable signal from the controller; and a sensing input logic signal normally high, but driven low responsive to the sensing of unacceptably high levels of radiation. A delay means is interposed between the controller and the AND gate, for delaying propagation of the write enable signal a sufficient amount of time to ensure that the sensing input to the AND gate responds to the detection of high radiation before the arrival of the write enable signal. The delay means can be an LC delay circuit, a coaxial cable, or a series of latches clocked in alternation order by opposite phases of an oscillator.
In some embodiments, a system includes a cosmic ray detector to detect cosmic rays and to generate cosmic ray detection signals indicative of the detected cosmic rays. The system also includes first circuitry to receive input signals and to produce output signals, and wherein the first circuitry speculates that the cosmic ray detector will not detect cosmic rays, but in response to the cosmic ray detection signals, the first circuitry re-performs at least some operations. Other embodiments are described and claimed.