Honeywell Information Systems Italia

Alessandro Scotti

Calogero Mantellina

Claudio Gentili

Ezio Cislaghi

Renzo Pederzini

A memory system wherein data is stored along with a SEC-DED error detecting and correcting code. Means are provided for selecting either a direct readout path for data from the memory when no readout errors have been detected for the memory address being accessed, or an alternate readout path including circuits for checking and correcting errors when an error condition has been detected. An auxiliary memory is provided for storing error flag bits indicating memory zones which have produced erroneous readouts, whereby the system is controlled such that high speed direct read cycles are executed for no-error memory zones and optimum memory accessing time is achieved without sacrificing the reliability achieved through use of the error correcting codes.

Memory with selective intervention error checking and correcting device

A semiconductor memory is provided with means for refreshing the memory. Interrupt requests generated by the memory initiate refreshing cycles, which take place in parallel with normal read/write memory operations. The memory is divided in two parts or blocks. If the central processor unit assigns a cycle for read/write operation to one of the two blocks, the same cycle is utilized to recharge or refresh a row of storage elements of the integrated units which constitute the other block of the memory. Refreshing is regulated by low priority interrupt requests and, if not responded to, by high priority interrupt requests, which are mandatory.

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Cornaredo, Italy

Alessandro Scotti