Memory systems and memory devices

Abstract

This invention improves the characteristics of a memory device. An embodiment of this invention provides a memory system comprising a memory device and an external machine. The memory device includes: a first wiring and a second wiring; a plurality of memory cells, each having a variable resistor and a switch electrically connected to the first wiring and the second wiring; a write circuit; and a read circuit. The memory system is configured to perform an adjustment process including a first process and a second process. In the first process, the read circuit performs a plurality of adjustment read operations, and the external machine generates first failure data for each of the plurality of memory cells. This first failure data stores whether the data read failed more than once in the plurality of read operations. In the second process, the write circuit performs a plurality of selection adjustment operations on target memory cells among the plurality of memory cells determined based on the first failure data.

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