Abstract: In a fault-tolerant system which is constructed from two control devices that operate in lockstep mode, e.g. both control devices are performing the same work at any given point in time, there is a requirement to check whether consistent, e.g. words identical, contents are being read from or written to the main memory at the same point in time in order to be able to detect any errors which may be occurring as quickly as possible and thus to prevent any spreading of the error. Known methods achieve this with the aid of dedicated north bridges which provide information by way of a separate interface, or by means of a monitoring of other operations, for example I/O transactions possibly on the PCI bus. According to the invention, the checking of the memory contents for consistency is performed with the aid of simple devices—memory monitoring module, checking device and is controlled by the checking device.

Abstract: An electrical circuit, which accepts an integrated circuit, which is supplied with operating voltages of different levels, and in which, between the supply voltages at their regular level, there is a diode function which is poled in the block direction. Such diode function preferably includes a Schottky diode between the circuit's terminals for the supply voltages at their regular levels, wherein the diode protects the circuit when the nominally low supply voltage has a higher voltage than the nominally high supply voltage.