Solid state memory (ssm), computer system including an ssm, and method of operating an ssm

Abstract

In one aspect, data is stored in a solid state memory which includes first and second memory layers. A first assessment is executed to determine whether received data is hot data or cold data. Received data which is assessed as hot data during the first assessment is stored in the first memory layer, and received data which is first assessed as cold data during the first assessment is stored in the second memory layer. Further, a second assessment is executed to determine whether the data stored in the first memory layer is hot data or cold data. Data which is then assessed as cold data during the second assessment is migrated from the first memory layer to the second memory layer.

1 . A method of storing data in a nonvolatile storage media having first and second memory layers, the method comprising:
 receiving a write command, an address and data from a host system;   determining whether a size of the data is less than a threshold size;   storing the data in the first memory layer if the size of the data is less than the threshold size; and   storing the data in the second memory layer if the size of the data is not less than the threshold size.   
     
     
         2 . The method of  claim 1 , wherein the threshold size is 32 KB. 
     
     
         3 . The method of  claim 1 , further comprising:
 determining if unused capacity of the first memory layer is less than a threshold capacity value;   when the unused capacity is less than the threshold capacity value, determining if a write count value of the data stored in the first memory layer is less than a threshold write count value; and   migrating the data stored in the first memory layer into the second memory layer if a write count value is less than the threshold write count value.   
     
     
         4 . The method of  claim 3 , wherein migrating the data stored in the first memory into the second memory is executed at periodic intervals or when the solid state memory enters an idle state. 
     
     
         5 . The method of  claim 1 , wherein an operation speed of the first memory layer is higher than an operation speed of the second memory layer. 
     
     
         6 . The method of  claim 1 , wherein the first memory layer comprises a single level cell (SLC) flash memory and the second memory layer comprises a multilevel cell (MLC) flash memory. 
     
     
         7 . A solid state memory comprising:
 a controller comprising a CPU (central process unit), a memory, a host interface, and an NVM (Nonvolatile memory) interface, the host interface configured to receive a write command, an address, and data from a host system, the CPU configured to determine whether a size of the data is less than a threshold size; and   a nonvolatile storage media comprising a first memory layer and a second memory layer, the first memory layer configured to store the data if the size of the data is less than a threshold size, and a second memory layer configured to store the data if the size of the data is not less than the threshold size.   
     
     
         8 . The solid state memory of  claim 7 , wherein the threshold size is 32 KB. 
     
     
         9 . The solid state memory of  claim 7 , wherein an operation speed of the first memory layer is higher than an operation speed of the second memory layer. 
     
     
         10 . The solid state memory of  claim 7 , wherein the first memory layer comprises a single level cell (SLC) flash memory and the second memory layer comprises a multilevel cell (MLC) flash memory. 
     
     
         11 . The solid state memory of  claim 7 , wherein the NVM interface is operatively connected to the first memory layer and the second memory layer to communicate. 
     
     
         12 . A solid state memory comprising:
 a controller comprising a CPU, a memory, a host interface, and an NVM interface,   the host interface configured to receive a write command, an address, and data from a host system, the CPU configured to determine whether the data is hot or cold;   a nonvolatile storage media comprising a first memory layer and a second memory layer, the first memory layer configured to store the data if the data is hot, the second memory layer configured to store the data if the data is cold,   wherein the NVM interface is operatively connected to the first memory layer and the second memory layer, the NVM interface and the first memory layer connected through a first channel and the NVM interface and the second memory layer connected through a second channel, the first channel and the second channel being separated from each other.   
     
     
         13 . The solid state memory of  claim 12 , wherein an operation speed of the first memory layer is higher than an operation speed of the second memory layer. 
     
     
         14 . The solid state memory of  claim 12 , wherein the first memory layer comprises a single level cell (SLC) flash memory and the second memory layer comprises a multilevel cell (MLC) flash memory. 
     
     
         15 . A controller for a solid state memory comprising:
 a CPU, a host interface, and an NVM interface;   the host interface configured to receive a write command, an address and data from a host system;   the CPU configured to determine whether a size of the data is less than a threshold size, the CPU instructing to transfer the data into a first memory layer if the size of the data is less than the threshold size and instructing to transfer the data into a second memory layer if the size of the data is not less than the threshold size, wherein an operation speed of the first memory layer is higher than an operation speed of the second memory layer.   
     
     
         16 . The controller of  claim 15 , wherein the threshold size is 32 KB. 
     
     
         17 . The controller of  claim 15 , wherein the first memory layer comprises a single level cell (SLC) flash memory and the second memory layer comprises a multilevel cell (MLC) flash memory. 
     
     
         18 . A method of storing data in a nonvolatile storage media having first and second memory layers, the method comprising:
 receiving a write command, an address and data from a host system;   determining whether an operating system of the host system has provided an information that the data is hot or cold;   storing the data in the first memory layer if the data is hot; and   storing the data in the second memory layer if the data is cold.   
     
     
         19 . The method of  claim 18 , further comprising:
 determining if unused capacity of the first memory layer is less than a threshold capacity value;   when the unused capacity is less than the threshold capacity value, determining if a write count value of the data stored in the first memory layer is less than a threshold write count value; and   migrating the data stored in the first memory layer into the second memory layer if a write count value is less than the threshold write count value.   
     
     
         20 . The method of  claim 19 , wherein migrating the data stored in the first memory into the second memory is executed at periodic intervals or when the solid state memory enters an idle state. 
     
     
         21 . The method of  claim 18 , wherein an operation speed of the first memory layer is higher than an operation speed of the second memory layer. 
     
     
         22 . The method of  claim 18 , wherein the first memory layer comprises a single level cell (SLC) flash memory and the second memory layer comprises a multilevel cell (MLC) flash memory.