MEMORY CONTROLLER THAT PROVIDES ADDRESSES TO HOST FOR MEMORY LOCATION MATCHING STATE TRACKED BY MEMORY CONTROLLER

摘要

This disclosure provides for host-controller cooperation in managing NAND flash memory. The controller maintains information for each erase unit which tracks memory usage. This information assists the host in making decisions about specific operations, for example, initiating garbage collection, space reclamation, wear leveling or other operations. For example, metadata can be provided to the host identifying whether each page of an erase unit has been released, and the host can specifically then command each of consolidation and erase using direct addressing. By redefining host-controller responsibilities in this manner, much of the overhead association with FTL functions can be substantially removed from the memory controller, with the host directly specifying physical addresses. This reduces performance unpredictability and overhead, thereby facilitating integration of solid state drives (SSDs) with other forms of storage. The disclosed techniques are especially useful for direct-attached and/or network-attached storage.

主权项

1. A memory controller to control nonvolatile memory to store and retrieve data at locations in the nonvolatile memory responsive to host commands, the memory controller comprising:
logic to maintain an entry for each of the locations in the nonvolatile memory capable of storing data responsive to the host commands, each entry representing status of the corresponding location in the nonvolatile memory independent of the values of any data stored at the corresponding location in the nonvolatile memory; and logic to send to the host an address of any given location in the nonvolatile memory capable of storing data responsive to the host commands where, according to the corresponding entry, the given location in the nonvolatile memory matches a specific status condition; wherein the memory controller is further to receive at least one ensuing host command in a manner that the at least one host command specifies the address sent to the host by the memory controller.