Storage device with geometry emulation based on division programming and decoupled NAND maintenance

A storage device comprising:

• flash memory having physical erase units;
• and
• circuitry to, for address information provided in association with each of incoming data write requests:
• derive from the incoming address information a first address portion, a second address portion and a third address portion,
• identify an addressed block device from the first address portion,
• identify an addressed segment within the addressed block device from the second address portion, and
• identify an addressed storage location within the addressed segment from the third address portion,
• wherein the circuitry is to subdivide the address information into bit fields, is to identify from a first one of the bit fields a logical erase unit within the addressed segment, and is to identify the addressed storage location dependent on the second one of the bit fields, and
• wherein the circuitry is to identify one of the physical erase units that corresponds to the identified logical erase unit, and
• program associated data into the identified one of the physical erase units at a location selected dependent on the addressed storage location;
• wherein the storage device also comprises circuitry to:
• maintain metadata for each physical erase unit which contains valid data, the metadata representing a time since data was programmed in the respective erase unit,
• copy data from a first one of the physical erase units for which the maintained metadata meets at least one criterion to a second one of the physical erase units, and, in association with said copy of the data, generate the metadata for the second one of the physical erase units so as to correspond to the copy of the data from the first one of the physical erase units to the second one of the physical erase units;
• and
• remap a correspondence of a logical erase unit which corresponds to the first one of the physical erase units to instead correspond to the second one of the physical erase units.

A storage device comprising:

• flash memory, the flash memory to have one or more block devices at a hierarchically-superior level, segments within each of the block devices at a hierarchically-intermediate level, and addressable storage locations within each of the segments at a hierarchically-inferior level, each segment including a mutually exclusive set of one or more logical erase units that each map to a physical erase unit, each segment being associated with only one of the block devices, each logical erase unit being associated with only one of the segments;
• and
• circuitry to, for each of incoming data write requests:
• derive, from incoming address information, a first address portion, a second address portion and a third address portion,
• identify an addressed one of the one or more block devices from the first address portion,
• identify an addressed one of the segments within the addressed block device from the second address portion, and
• identify an addressed storage location within the addressed one of the segments from the third address portion,
• wherein the circuitry is to use a division operation on at least one of the incoming address information or information derived from the incoming address information, to identify a logical erase unit within the addressed one of the segments, and
• wherein the circuitry is to identify one of the physical erase units that corresponds to the identified logical erase unit, and
• program associated data into the identified one of the physical erase units;
• wherein the storage device also comprises circuitry to:
• maintain metadata for each physical erase unit which contains data, the metadata representing a time since data was programmed in the respective erase unit,
• copy data from a first one of the physical erase units for which the maintained metadata meets at least one criterion to a second one of the physical erase units, and, in association with said copy of the data, generate the metadata for the second one of the physical erase units so as to correspond to the copy of the data;
• and
• remap a correspondence of a logical erase unit which corresponds to the first one of the physical erase units to instead correspond to the second one of the physical erase units;
• and
• wherein the storage device is to generate the metadata for the second one of the physical erase units so as to correspond to a time that the data was copied from the first one of the physical erase units to the second one of the physical erase units.