device for the identification of a faulty bitplan at several bitplan, as organised in the form of a matrix in a solid state memory device

摘要

A maintenance procedure comprising a method of and an apparatus for storing information identifying the location of one or more defective bits, i.e., a defective memory element, a defective storage device or a failure, in a single-error-correcting semiconductor main storage unit (MSU) comprised of a plurality of replaceable large scale integrated (LSI) bit planes. The method utilizes an error logging store (ELS) that is comprised of a plurality of word-group-associated registers which hold the address data that identifies the replaceable LSI bit planes of the MSU in which a correctable error has been detected. After each detection of a correctable error, the address data is compared to address data already stored in the ELS. If the comparison indicates that it is new address data, i.e., that that bit plane has not previously caused a correctable error, the address data is entered into the ELS, shifting all previous entries one stage. After a predetermined number of defective bit plane addresses, i.e., address data, are stored therein a signal is generated to alert the machine operator to schedule preventive maintenance of the MSU by replacing the defective bit planes. By statistically determining the number of allowable failures, i.e., the number of correctable failures that may occur before the expected occurrence of a non-correctable double bit error, preventive maintenance may be scheduled only as required by the particular MSU.