US 2021/0200676 A1 · Apparatus and Method of Read Leveling for Storage Class Memory

Abstract

A method and apparatus for read wearing control for storage class memory (SCM) are disclosed. The read data control apparatus, located between a host and the SCM subsystem, comprises a read data cache, an address cache and an SCM controller. The address cache stores pointers pointing to data stored in logging area(s) located in the SCM. For a read request, the read wearing control determines whether the read request is a read data cache hit, an address cache hit or neither (i.e., read data cache miss and address cache miss). For the read data cache hit, the requested data is returned from the read data cache. For the address cache hit, the requested data is returned from the logging area(s) and the read data becomes a candidate to be placed in the read data cache. For read data cache and address cache misses, the requested data is returned from SCM.

Claims16

Dependent claims

A method of read wear-leveling control for SCM (Storage Class Memory) based on nonvolatile memory, the method comprising:

determining whether current read data requested by a host as indicated by a request address is a read-data-cache hit, an address-cache hit, or both read-data-cache miss and address-cache miss;
when the read-data-cache hit is determined, providing the current read data from a read data cache;
when the address-cache hit is determined, providing the current read data from one logging area of the SCM at an SCM address as pointed by a pointer in an address cache;
and
when both the read-data-cache miss and the address-cache miss are determined, providing the current read data from a regular storage area of the SCM.

2 more elements

Dependencies are inferred from the claim text.

Apparatus and Method of Read Leveling for Storage Class Memory

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Apparatus and Method of Read Leveling for Storage Class Memory

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Abstract

Claims16